Giardia spp. is detected frequently in humans and animals. Although many studies have been conduc... more Giardia spp. is detected frequently in humans and animals. Although many studies have been conducted on the epidemiology of giardiasis, there is a scarcity of information on the genetic diversity and the dynamics of transmission of Giardia spp. in Vietnam. The zoonotic potential of Giardia spp. remains elusive. The objective of this study was to determine the genetic diversity of Giardia spp. in both humans and livestock to assess the existence of a route of infection between livestock and humans. Our goal was to assess the role animals play in the epidemiology of human infection in northern Vietnam. In Hien Khanh commune in northern Vietnam, 311 households with 1508 residents were randomly selected for a diarrheal cohort study. Of these, 2120 human diarrheal samples were collected from 1508 residents in 2014 and 2017. Of these, non-diarrheal samples were cross-sectionally collected from 471 residents. At the same site, livestock samples from buffalo, dairy and beef cattle, pigs, and dogs were collected. All stool samples were examined for Giardia spp. by Direct Immunofluorescence Assay (DFA) using fluorescent microscope. DNA extraction, PCR analysis of the 3 genes (bg, gdh, tpi), and sequencing analysis were continuously carried out. A total of 23 animal stool samples, 8 human non-diarrheal samples, and 36 human diarrheal samples were Giardia spp. were positive by PCR using the bg and gdh genes. Giardia spp. assemblage AII and E were detected in both animal samples and human samples in this study site. The detection of assemblage E in human stool samples suggests the first human case report in Vietnam. We assume that the unexpected human infection of all Giardia assemblages including A, B, and E may be due to an environment contaminated with animal and human feces in this village.
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
study area (5.6) is much greater than that in developed countries such as USA (2.6 in 2006, US Ce... more study area (5.6) is much greater than that in developed countries such as USA (2.6 in 2006, US Census Bureau) and Japan (2.6 in 2005, Ministry of Internal Affairs and Communications). Thus, many nonsmoking household members may share indoor environments with smokers. The WHO FCTC is the first global public health treaty that the 166 WHO member states have already ratified. 3 Article 8 of the WHO FCTC addresses the issue of protection from exposure to tobacco smoke in public places, however, there’s no statement on protection from domestic SHS. Despite the lack of biological data, our results clearly indicate that SHS exposure occurs in public places and also in households. For women and children in particular, the household likely represents the primary location of exposure. 6 Public educational campaigns for smoke-free homes 7 8 are warranted in Southeast Asian countries, to protect women and children who remain exposed to SHS at home. Acknowledgements We thank all of the project
Rotavirus (RV), Norovirus (NV), Sapovirus (SaV) and Astrovirus (Ast) are the leading causes of ga... more Rotavirus (RV), Norovirus (NV), Sapovirus (SaV) and Astrovirus (Ast) are the leading causes of gastroenteritis and mortality in children worldwide. RV vaccines help to reduce the burden of diarrhea while the importance of other viruses is increasing. Therefore, we conducted a cross-sectional descriptive study to determine prevalence of these viruses in hospitalized children under 5 years old in Nam Dinh province with approximately 80% of RV vaccine coverage. We randomly selected 579 (25%) among diarrheal samples collected in 4 district hospitals from Dec. 2017 to Nov. 2019. An ELISA kit was employed to detect RV and the multiplex real-time RT-PCR with specific primers to detect NV, SaV and Ast. These viruses were found among 64.3% of hospitalized children, of which NV and RV were present in 28.5% and 21.4%, respectively, while SaV and Ast were detected in 3.3% and 2.6%, respectively. Co-infections accounted for 8.5%, mainly among RV and 3 other viruses. There is a significant difference in RV and NV positive rates between vaccinated and unvaccinated groups (p < 0.001 and p = 0.008, respectively). This study contributed to the understanding of the potential impact of rotavirus vaccine on other diarheal pathogens and emphasize the need for further epidemiological studies when the nationwide RV vaccination in Vietnam is implementing.
Bulletin of The World Health Organization, Feb 24, 2014
Objective To characterize influenza seasonality and identify the best time of the year for vaccin... more Objective To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and southeastern Asia that lie north of the equator. Methods Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries. Findings Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator. Conclusion Most southern and southeastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.
Một nghiên cứu mô tả cắt ngang được thực hiện tại 63/63 tỉnh/thành phố ở Việt Nam từ năm 2010 đến... more Một nghiên cứu mô tả cắt ngang được thực hiện tại 63/63 tỉnh/thành phố ở Việt Nam từ năm 2010 đến năm 2019 nhằm mô tả thực trạng tiêm vắc xin viêm gan B liều sơ sinh tại Việt Nam. Kết quả cho thấy, tỷ lệ tiêm vắc xin viêm gan B (VGB) liều sơ sinh ở Việt Nam giai đoạn 2010 - 2019 là 70,5%, trong đó tỷ lệ tiêm vắc xin VGB liều sơ sinh trước 24 giờ và sau sinh 24 giờ lần lượt là 63,2% và 7,3%. Có sự khác biệt giữa các vùng kinh tế - xã hội (p < 0,01). Tỷ lệ tiêm vắc xin VGB liều sơ sinh cao nhất là 78,0% ở vùng Đồng bằng sông Cửu Long và thấp nhất là 55,5% ở vùng Trung du và miền núi phía Bắc. Tỷ lệ tiêm vắc xin VGB liều sơ sinh ở Việt Nam trong giai đoạn 2010 - 2019 còn thấp, có sự thay đổi không đồng đều giữa các năm và các vùng kinh tế - xã hội ở Việt Nam. Cần tăng cường tỷ lệ tiêm vắc xin VGB liều sơ sinh, đặc biệt là tiêm trong vòng 24 giờ sau sinh.
International Journal of Infectious Diseases, Jun 1, 2012
Background: Improvements in water and sanitation are essential to reducing the burden of many inf... more Background: Improvements in water and sanitation are essential to reducing the burden of many infectious diseases, most notably that of diarrhea and enteric fevers. Vietnam has considerable burden of enteric diseases including typhoid fever. The objective of this study was to retrospectively review epidemiological data on typhoid fever and environmental data that are often considered to be associated with typhoid fever in Vietnam over a period of 10 years from 1991 to 2001 to understand the trend and environmental risk factors of typhoid fever in Vietnam. Methods: Government of Vietnam collects data on typhoid fever by provinces. This government data was collected as part of the Existing Data Collection study under the Diseases of the Most Impoverished (DOMI) program of the International Vaccine Institute conducted between 1999 and 2007 and was retrospectively analyzed. In addition, the government provincial data on urbanization, water and sanitation status was compared for all provinces against incidence of reported typhoid fever and plotted in scatter diagram for the risk factor analysis. Retrospective data on typhoid vaccine coverage was collected from the National Institute of Hygiene and Epidemiology. Results: The annual incidence of typhoid fever in Vietnam varied over the first five years increasing from an incidence rate of 12/100,000 in 1991 to over 40/100,000 in 1995 and decreasing during the later five years from 35/100,000 in 1996 to 12/100,000 in 2001. There was seasonal variation with peak incidence from May to August. On the risk factor analysis for typhoid, urbanization, access to clean water, or access to sanitation were not statistically related to typhoid fever incidence. Conclusion: Based on the review of 10-year typhoid fever incidence data coinciding with the introduction of typhoid fever vaccine in Vietnam, improvement in water and sanitation alone did not appear to be significantly related to the reduction in the incidence of typhoid fever. The Government of Vietnam started typhoid vaccination in high-risk districts from 1997 which have contributed in reduction of typhoid fever in these districts. It is important to complement the preventive efforts with introduction of vaccines in the short to intermediate term to effectively control typhoid fever.
Shigella spp. are exquisitely fastidious gram-negative organisms which frequently escape detectio... more Shigella spp. are exquisitely fastidious gram-negative organisms which frequently escape detection by traditional culture methods. To get a more complete understanding of the disease burden caused by Shigella in Nha Trang, Vietnam, real-time PCR was used to detect Shigella DNA. Randomly selected rectal swab specimens from 60 Shigella culture-positive patients and 500 Shigella culture-negative patients detected by populationbased surveillance of patients seeking care for diarrhea were processed by real-time PCR. The target of the primer pair is the invasion plasmid antigen H gene sequence (ipaH), carried by all four Shigella species and enteroinvasive Escherichia coli. Shigella spp. could be isolated from the rectal swabs of 547 of 19,206 (3%) patients with diarrhea. IpaH was detected in 55 of 60 (93%) Shigella culture-positive specimens, whereas it was detected in 87 of 245 (36%) culture-negative patients free of dysentery (P < 0.001). The number of PCR cycles required to detect a PCR product was highest for culture-negative, nonbloody diarrheal specimens (mean number of cycles to detection, 36.6) and was lowest for children with culture-positive, bloody diarrheal specimens (mean number of cycles, 25.3) (P < 0.001). The data from real-time PCR amplification indicate that the culture-proven prevalence of Shigella among patients with diarrhea may underestimate the prevalence of Shigella infections. The clinical presentation of shigellosis may be directly related to the bacterial load.
Rotavirus vaccine has proved effective for prevention of severe rotavirus gastroenteritis in infa... more Rotavirus vaccine has proved effective for prevention of severe rotavirus gastroenteritis in infants in developed countries, but no efficacy studies have been done in developing countries in Asia. We assessed the clinical efficacy of live oral pentavalent rotavirus vaccine for prevention of severe rotavirus gastroenteritis in infants in Bangladesh and Vietnam. In this multicentre, double-blind, placebo-controlled trial, undertaken in rural Matlab, Bangladesh, and urban and periurban Nha Trang, Vietnam, infants aged 4-12 weeks without symptoms of gastrointestinal disorders were randomly assigned (1:1) to receive three oral doses of pentavalent rotavirus vaccine 2 mL or placebo at around 6 weeks, 10 weeks, and 14 weeks of age, in conjunction with routine infant vaccines including oral poliovirus vaccine. Randomisation was done by computer-generated randomisation sequence in blocks of six. Episodes of gastroenteritis in infants who presented to study medical facilities were reported by clinical staff and from parent recollection. The primary endpoint was severe rotavirus gastroenteritis (Vesikari score &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=11) arising 14 days or more after the third dose of placebo or vaccine to end of study (March 31, 2009; around 21 months of age). Analysis was per protocol; infants who received scheduled doses of vaccine or placebo without intervening laboratory-confirmed naturally occurring rotavirus disease earlier than 14 days after the third dose and had complete clinical and laboratory results were included in the analysis. This study is registered with ClinicalTrials.gov, number NCT00362648. 2036 infants were randomly assigned to receive pentavalent rotavirus vaccine (n=1018) or placebo (n=1018). 991 infants assigned to pentavalent rotavirus vaccine and 978 assigned to placebo were included in the per-protocol analysis. Median follow up from 14 days after the third dose of placebo or vaccine until final disposition was 498 days (IQR 480-575). 38 cases of severe rotavirus gastroenteritis (Vesikari score &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=11) were reported during more than 1197 person-years of follow up in the vaccine group, compared with 71 cases in more than 1156 person years in the placebo group, resulting in a vaccine efficacy of 48.3% (95% CI 22.3-66.1) against severe disease (p=0.0005 for efficacy…
We tested a candidate live, oral, rotavirus vaccine (Rotavin-M1 TM) derived from an attenuated G1... more We tested a candidate live, oral, rotavirus vaccine (Rotavin-M1 TM) derived from an attenuated G1P [8] strain (KH0118-2003) isolated from a child in Vietnam. The vaccine was tested first for safety in 29 healthy adults. When deemed safe, it was further tested for safety and immunogenicity in 160 infants (4 groups) aged 6-12 weeks in a dose and schedule ranging study. The vaccine was administered in low titer (10 6.0 FFU/dose) on a 2-dose schedule given 2 months apart (Group 2L) and on a 3-dose schedule given 1 month apart (Group 3L) and in high titer (10 6.3 FFU/dose) in 2 doses 2 months apart (Group 2H) and in 3 doses 1 month apart (Group 3H). For comparison, 40 children (group Rotarix TM) were given 2 doses of the lyophilized Rotarix TM vaccine (10 6.5 CCID 50 /dose) 1 month apart. All infants were followed for 30 days after each dose for clinical adverse events including diarrhea, vomiting, fever, abdominal pain, irritability and intussusception. Immunogenicity was assessed by IgA seroconversion and viral shedding was monitored for 7 days after administration of each dose. Two doses of Rotavin-M1 (10 6.3 FFU/dose) were well tolerated in adults. Among infants (average 8 weeks of age at enrollment), administration of Rotavin-M1 was safe and did not lead to an increased rate of fever, diarrhea, vomiting or irritability compared to Rotarix TM , indicating that the candidate vaccine virus had been fully attenuated by serial passages. No elevation of levels of serum transaminase, blood urea, or blood cell counts were observed. The highest rotavirus IgA seroconversion rate (73%, 95%CI (58-88%)) was achieved in group 2H (2 doses-10 6.3 FFU/dose, 2 months apart). The 2 dose schedules performed slightly better than the 3 dose schedules and the higher titer doses performed slightly better than the lower titer doses. These rates of seroconversion were similar to that of the Rotarix TM group (58%, 95%CI (42-73%)). However more infants who received Rotarix TM (65%) shed virus in their stool after the first dose than those who received Rotavin-M1 (44-48%) (p < 0.05) and the percent shedding decreased after subsequent doses of either vaccine. Rotavin-M1 vaccine is safe and immunogenic in Vietnamese infants. A trial in progress will assess the safety, immunogenicity and efficacy of Rotavin-M1 (2 doses at 10 6.3 FFU/dose) in a larger number of infants. The trial registration numbers are NCT01375907 and NCT01377571.
International Journal of Infectious Diseases, 2018
To describe the immunogenicity and safety of the Japanese encephalitis chimeric virus vaccine (JE... more To describe the immunogenicity and safety of the Japanese encephalitis chimeric virus vaccine (JE-CV) in children and adults in Vietnam. Methods: In this prospective, open-label, single-center, single-arm study, 250 healthy participants aged 9 months to 60 years received a single dose of JE-CV (IMOJEV 1). JE neutralizing antibody titers were assessed at baseline and 28 days after vaccination using the 50% plaque reduction neutralization test (PRNT 50). Safety and reactogenicity were assessed through solicited and unsolicited adverse events. Findings: Seroconversion (titer 10 [1/dil] in participants JE seronegative [titer <10] at baseline [per protocol analysis], or a 4-fold rise from a baseline titer 10) and seroprotection (titer 10 [1/dil]) rates 28 days after vaccination were both 98.5% (132/134) in the per protocol analysis, and 82.4% (201/244) and 98.8% (242/245), respectively, in the full analysis set. Geometric mean titers (GMTs) increased in all age groups from Day 0 to Day 28; Day 28/Day 0 GMT ratios were 55.3 (95% confidence interval [CI] 38.4-79.8), 348 (95% CI 211-572), 296 (95% CI 152-576) and 194 (95% CI 13.1-2870) in those aged 9 months to 4 years, 5-11 years, 12-17 years and 18-60 years, respectively, in the per protocol analysis. There were no safety concerns during the study. Conclusion: A single dose of JE-CV in children and adults aged 9 months to 60 years in Vietnam elicited a protective immune response and was well tolerated with no safety concerns. Registered at www.clinicaltrials.gov (NCT02492165).
Background: A phase III, randomized, double-blind, placebo-controlled clinical study was conducte... more Background: A phase III, randomized, double-blind, placebo-controlled clinical study was conducted in China to assess the efficacy, safety, and immunogenicity of the pentavalent rotavirus vaccine (RotaTeq TM , RV5) among Chinese infants. The efficacy and safety data have been previously reported. This report presents the immunogenicity data of the study. Methods: 4,040 infants aged 6-12 weeks were randomly assigned in a 1:1 ratio to receive 3 oral doses of RV5 or placebo. Trivalent oral poliovirus vaccine (tOPV) and diphtheria, tetanus, and acellular pertussis vaccine (DTaP) were administered in a staggered-use (N = 3,240) or concomitant-use (N = 800) schedule. Immunogenicity of RV5 was evaluated in 800 participants (400 participants from each staggered-and concomitant-use immunogenicity subgroup). Geometric mean titers (GMTs) and seroresponse rates (!3-fold rise from baseline to PD3) were measured for anti-rotavirus IgA in the staggered-and concomitant-use subgroups and measured for serum neutralizing antibodies (SNAs) to human rotavirus serotypes G1, G2, G3, G4, P1A[8] in the staggered-use subgroup. Immune responses to tOPV and DTaP coadministered with RV5 were also evaluated in the concomitant-use immunogenicity subgroup. (ClinicalTrials.gov registry: NCT02062385) Results: The PD3 GMT and seroresponse rate of anti-rotavirus IgA were higher in the RV5 group (82.42 units/mL, 89.4%) compared to the placebo group (0.33 units/mL, 10.1%). Rotavirus type-specific SNA responses were also higher in the RV5 group compared to the placebo group. In the concomitant-use subgroup, the seroprotection rates of anti-poliovirus type 1, 2, 3 in the participants who received RV5 were non-inferior to those who received placebo, and the antibody responses to DTaP antigens were comparable between the two vaccination groups. Conclusions: RV5 was immunogenic in Chinese infants. Immune responses induced by tOPV and DTaP were not affected by the concomitant use of RV5.
Objective To characterize influenza seasonality and identify the best time of the year for vaccin... more Objective To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and southeastern Asia that lie north of the equator. Methods Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries. Findings Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator. Conclusion Most southern and southeastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.
Bulletin of The World Health Organization, Feb 1, 2011
is a low-income country with an estimated total population of 87 million. According to data from ... more is a low-income country with an estimated total population of 87 million. According to data from the United Nations Children's Fund, from 2003 to 2008 the average annual number of births in the country was 1 494 000 and the average annual prevalence of low birth weight was 7%. In 2008, the maternal mortality ratio was 150 per Abstracts in ,عريب 中文, Français, Pусский and Español at the end of each article. Objective To examine the association between gestational weight gain and maternal body mass index (BMI) among Vietnamese women and the risk of delivering an infant too small or too large for gestational age. Methods A prospective health-facility-based study of 2989 pregnant Vietnamese women was conducted in the city of Nha Trang in 2007-2008. Cubic logistic regression was used to investigate the association of interest. Infants were classified into weight-forgestational-age categories according to weight centiles for the Asian population. Gestational age was based on the date of last menstrual period and adjusted by the results of first-trimester ultrasound. Findings BMI was low (< 18.5), normal (18.5-22.9) and high (≥ 23.0) in 26.1%, 65.4% and 8.5% of the women, respectively. In each of these BMI categories, the percentage of women who delivered infants too small for gestational age was 18.1, 10.0 and 9.4, respectively, and the mean gestational weight gain was 12.5 kg (standard deviation, SD: ± 3.6), 12.2 kg (SD: ± 3.8) and 11.5 kg (SD: ± 4.7), respectively. Among women with low BMI, the risk of delivering an infant too small for gestational age ranged from approximately 40% if the gestational weight gain was < 5 kg to 20% if it was 5-10 kg. Conclusion Having a low BMI, commonly found in Viet Nam, puts women at risk of delivering an infant too small for gestational age, especially when total maternal gestational weight gain is < 10 kg.
Giardia spp. is detected frequently in humans and animals. Although many studies have been conduc... more Giardia spp. is detected frequently in humans and animals. Although many studies have been conducted on the epidemiology of giardiasis, there is a scarcity of information on the genetic diversity and the dynamics of transmission of Giardia spp. in Vietnam. The zoonotic potential of Giardia spp. remains elusive. The objective of this study was to determine the genetic diversity of Giardia spp. in both humans and livestock to assess the existence of a route of infection between livestock and humans. Our goal was to assess the role animals play in the epidemiology of human infection in northern Vietnam. In Hien Khanh commune in northern Vietnam, 311 households with 1508 residents were randomly selected for a diarrheal cohort study. Of these, 2120 human diarrheal samples were collected from 1508 residents in 2014 and 2017. Of these, non-diarrheal samples were cross-sectionally collected from 471 residents. At the same site, livestock samples from buffalo, dairy and beef cattle, pigs, and dogs were collected. All stool samples were examined for Giardia spp. by Direct Immunofluorescence Assay (DFA) using fluorescent microscope. DNA extraction, PCR analysis of the 3 genes (bg, gdh, tpi), and sequencing analysis were continuously carried out. A total of 23 animal stool samples, 8 human non-diarrheal samples, and 36 human diarrheal samples were Giardia spp. were positive by PCR using the bg and gdh genes. Giardia spp. assemblage AII and E were detected in both animal samples and human samples in this study site. The detection of assemblage E in human stool samples suggests the first human case report in Vietnam. We assume that the unexpected human infection of all Giardia assemblages including A, B, and E may be due to an environment contaminated with animal and human feces in this village.
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
study area (5.6) is much greater than that in developed countries such as USA (2.6 in 2006, US Ce... more study area (5.6) is much greater than that in developed countries such as USA (2.6 in 2006, US Census Bureau) and Japan (2.6 in 2005, Ministry of Internal Affairs and Communications). Thus, many nonsmoking household members may share indoor environments with smokers. The WHO FCTC is the first global public health treaty that the 166 WHO member states have already ratified. 3 Article 8 of the WHO FCTC addresses the issue of protection from exposure to tobacco smoke in public places, however, there’s no statement on protection from domestic SHS. Despite the lack of biological data, our results clearly indicate that SHS exposure occurs in public places and also in households. For women and children in particular, the household likely represents the primary location of exposure. 6 Public educational campaigns for smoke-free homes 7 8 are warranted in Southeast Asian countries, to protect women and children who remain exposed to SHS at home. Acknowledgements We thank all of the project
Rotavirus (RV), Norovirus (NV), Sapovirus (SaV) and Astrovirus (Ast) are the leading causes of ga... more Rotavirus (RV), Norovirus (NV), Sapovirus (SaV) and Astrovirus (Ast) are the leading causes of gastroenteritis and mortality in children worldwide. RV vaccines help to reduce the burden of diarrhea while the importance of other viruses is increasing. Therefore, we conducted a cross-sectional descriptive study to determine prevalence of these viruses in hospitalized children under 5 years old in Nam Dinh province with approximately 80% of RV vaccine coverage. We randomly selected 579 (25%) among diarrheal samples collected in 4 district hospitals from Dec. 2017 to Nov. 2019. An ELISA kit was employed to detect RV and the multiplex real-time RT-PCR with specific primers to detect NV, SaV and Ast. These viruses were found among 64.3% of hospitalized children, of which NV and RV were present in 28.5% and 21.4%, respectively, while SaV and Ast were detected in 3.3% and 2.6%, respectively. Co-infections accounted for 8.5%, mainly among RV and 3 other viruses. There is a significant difference in RV and NV positive rates between vaccinated and unvaccinated groups (p &lt; 0.001 and p = 0.008, respectively). This study contributed to the understanding of the potential impact of rotavirus vaccine on other diarheal pathogens and emphasize the need for further epidemiological studies when the nationwide RV vaccination in Vietnam is implementing.
Bulletin of The World Health Organization, Feb 24, 2014
Objective To characterize influenza seasonality and identify the best time of the year for vaccin... more Objective To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and southeastern Asia that lie north of the equator. Methods Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries. Findings Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator. Conclusion Most southern and southeastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.
Một nghiên cứu mô tả cắt ngang được thực hiện tại 63/63 tỉnh/thành phố ở Việt Nam từ năm 2010 đến... more Một nghiên cứu mô tả cắt ngang được thực hiện tại 63/63 tỉnh/thành phố ở Việt Nam từ năm 2010 đến năm 2019 nhằm mô tả thực trạng tiêm vắc xin viêm gan B liều sơ sinh tại Việt Nam. Kết quả cho thấy, tỷ lệ tiêm vắc xin viêm gan B (VGB) liều sơ sinh ở Việt Nam giai đoạn 2010 - 2019 là 70,5%, trong đó tỷ lệ tiêm vắc xin VGB liều sơ sinh trước 24 giờ và sau sinh 24 giờ lần lượt là 63,2% và 7,3%. Có sự khác biệt giữa các vùng kinh tế - xã hội (p < 0,01). Tỷ lệ tiêm vắc xin VGB liều sơ sinh cao nhất là 78,0% ở vùng Đồng bằng sông Cửu Long và thấp nhất là 55,5% ở vùng Trung du và miền núi phía Bắc. Tỷ lệ tiêm vắc xin VGB liều sơ sinh ở Việt Nam trong giai đoạn 2010 - 2019 còn thấp, có sự thay đổi không đồng đều giữa các năm và các vùng kinh tế - xã hội ở Việt Nam. Cần tăng cường tỷ lệ tiêm vắc xin VGB liều sơ sinh, đặc biệt là tiêm trong vòng 24 giờ sau sinh.
International Journal of Infectious Diseases, Jun 1, 2012
Background: Improvements in water and sanitation are essential to reducing the burden of many inf... more Background: Improvements in water and sanitation are essential to reducing the burden of many infectious diseases, most notably that of diarrhea and enteric fevers. Vietnam has considerable burden of enteric diseases including typhoid fever. The objective of this study was to retrospectively review epidemiological data on typhoid fever and environmental data that are often considered to be associated with typhoid fever in Vietnam over a period of 10 years from 1991 to 2001 to understand the trend and environmental risk factors of typhoid fever in Vietnam. Methods: Government of Vietnam collects data on typhoid fever by provinces. This government data was collected as part of the Existing Data Collection study under the Diseases of the Most Impoverished (DOMI) program of the International Vaccine Institute conducted between 1999 and 2007 and was retrospectively analyzed. In addition, the government provincial data on urbanization, water and sanitation status was compared for all provinces against incidence of reported typhoid fever and plotted in scatter diagram for the risk factor analysis. Retrospective data on typhoid vaccine coverage was collected from the National Institute of Hygiene and Epidemiology. Results: The annual incidence of typhoid fever in Vietnam varied over the first five years increasing from an incidence rate of 12/100,000 in 1991 to over 40/100,000 in 1995 and decreasing during the later five years from 35/100,000 in 1996 to 12/100,000 in 2001. There was seasonal variation with peak incidence from May to August. On the risk factor analysis for typhoid, urbanization, access to clean water, or access to sanitation were not statistically related to typhoid fever incidence. Conclusion: Based on the review of 10-year typhoid fever incidence data coinciding with the introduction of typhoid fever vaccine in Vietnam, improvement in water and sanitation alone did not appear to be significantly related to the reduction in the incidence of typhoid fever. The Government of Vietnam started typhoid vaccination in high-risk districts from 1997 which have contributed in reduction of typhoid fever in these districts. It is important to complement the preventive efforts with introduction of vaccines in the short to intermediate term to effectively control typhoid fever.
Shigella spp. are exquisitely fastidious gram-negative organisms which frequently escape detectio... more Shigella spp. are exquisitely fastidious gram-negative organisms which frequently escape detection by traditional culture methods. To get a more complete understanding of the disease burden caused by Shigella in Nha Trang, Vietnam, real-time PCR was used to detect Shigella DNA. Randomly selected rectal swab specimens from 60 Shigella culture-positive patients and 500 Shigella culture-negative patients detected by populationbased surveillance of patients seeking care for diarrhea were processed by real-time PCR. The target of the primer pair is the invasion plasmid antigen H gene sequence (ipaH), carried by all four Shigella species and enteroinvasive Escherichia coli. Shigella spp. could be isolated from the rectal swabs of 547 of 19,206 (3%) patients with diarrhea. IpaH was detected in 55 of 60 (93%) Shigella culture-positive specimens, whereas it was detected in 87 of 245 (36%) culture-negative patients free of dysentery (P < 0.001). The number of PCR cycles required to detect a PCR product was highest for culture-negative, nonbloody diarrheal specimens (mean number of cycles to detection, 36.6) and was lowest for children with culture-positive, bloody diarrheal specimens (mean number of cycles, 25.3) (P < 0.001). The data from real-time PCR amplification indicate that the culture-proven prevalence of Shigella among patients with diarrhea may underestimate the prevalence of Shigella infections. The clinical presentation of shigellosis may be directly related to the bacterial load.
Rotavirus vaccine has proved effective for prevention of severe rotavirus gastroenteritis in infa... more Rotavirus vaccine has proved effective for prevention of severe rotavirus gastroenteritis in infants in developed countries, but no efficacy studies have been done in developing countries in Asia. We assessed the clinical efficacy of live oral pentavalent rotavirus vaccine for prevention of severe rotavirus gastroenteritis in infants in Bangladesh and Vietnam. In this multicentre, double-blind, placebo-controlled trial, undertaken in rural Matlab, Bangladesh, and urban and periurban Nha Trang, Vietnam, infants aged 4-12 weeks without symptoms of gastrointestinal disorders were randomly assigned (1:1) to receive three oral doses of pentavalent rotavirus vaccine 2 mL or placebo at around 6 weeks, 10 weeks, and 14 weeks of age, in conjunction with routine infant vaccines including oral poliovirus vaccine. Randomisation was done by computer-generated randomisation sequence in blocks of six. Episodes of gastroenteritis in infants who presented to study medical facilities were reported by clinical staff and from parent recollection. The primary endpoint was severe rotavirus gastroenteritis (Vesikari score &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=11) arising 14 days or more after the third dose of placebo or vaccine to end of study (March 31, 2009; around 21 months of age). Analysis was per protocol; infants who received scheduled doses of vaccine or placebo without intervening laboratory-confirmed naturally occurring rotavirus disease earlier than 14 days after the third dose and had complete clinical and laboratory results were included in the analysis. This study is registered with ClinicalTrials.gov, number NCT00362648. 2036 infants were randomly assigned to receive pentavalent rotavirus vaccine (n=1018) or placebo (n=1018). 991 infants assigned to pentavalent rotavirus vaccine and 978 assigned to placebo were included in the per-protocol analysis. Median follow up from 14 days after the third dose of placebo or vaccine until final disposition was 498 days (IQR 480-575). 38 cases of severe rotavirus gastroenteritis (Vesikari score &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;or=11) were reported during more than 1197 person-years of follow up in the vaccine group, compared with 71 cases in more than 1156 person years in the placebo group, resulting in a vaccine efficacy of 48.3% (95% CI 22.3-66.1) against severe disease (p=0.0005 for efficacy…
We tested a candidate live, oral, rotavirus vaccine (Rotavin-M1 TM) derived from an attenuated G1... more We tested a candidate live, oral, rotavirus vaccine (Rotavin-M1 TM) derived from an attenuated G1P [8] strain (KH0118-2003) isolated from a child in Vietnam. The vaccine was tested first for safety in 29 healthy adults. When deemed safe, it was further tested for safety and immunogenicity in 160 infants (4 groups) aged 6-12 weeks in a dose and schedule ranging study. The vaccine was administered in low titer (10 6.0 FFU/dose) on a 2-dose schedule given 2 months apart (Group 2L) and on a 3-dose schedule given 1 month apart (Group 3L) and in high titer (10 6.3 FFU/dose) in 2 doses 2 months apart (Group 2H) and in 3 doses 1 month apart (Group 3H). For comparison, 40 children (group Rotarix TM) were given 2 doses of the lyophilized Rotarix TM vaccine (10 6.5 CCID 50 /dose) 1 month apart. All infants were followed for 30 days after each dose for clinical adverse events including diarrhea, vomiting, fever, abdominal pain, irritability and intussusception. Immunogenicity was assessed by IgA seroconversion and viral shedding was monitored for 7 days after administration of each dose. Two doses of Rotavin-M1 (10 6.3 FFU/dose) were well tolerated in adults. Among infants (average 8 weeks of age at enrollment), administration of Rotavin-M1 was safe and did not lead to an increased rate of fever, diarrhea, vomiting or irritability compared to Rotarix TM , indicating that the candidate vaccine virus had been fully attenuated by serial passages. No elevation of levels of serum transaminase, blood urea, or blood cell counts were observed. The highest rotavirus IgA seroconversion rate (73%, 95%CI (58-88%)) was achieved in group 2H (2 doses-10 6.3 FFU/dose, 2 months apart). The 2 dose schedules performed slightly better than the 3 dose schedules and the higher titer doses performed slightly better than the lower titer doses. These rates of seroconversion were similar to that of the Rotarix TM group (58%, 95%CI (42-73%)). However more infants who received Rotarix TM (65%) shed virus in their stool after the first dose than those who received Rotavin-M1 (44-48%) (p < 0.05) and the percent shedding decreased after subsequent doses of either vaccine. Rotavin-M1 vaccine is safe and immunogenic in Vietnamese infants. A trial in progress will assess the safety, immunogenicity and efficacy of Rotavin-M1 (2 doses at 10 6.3 FFU/dose) in a larger number of infants. The trial registration numbers are NCT01375907 and NCT01377571.
International Journal of Infectious Diseases, 2018
To describe the immunogenicity and safety of the Japanese encephalitis chimeric virus vaccine (JE... more To describe the immunogenicity and safety of the Japanese encephalitis chimeric virus vaccine (JE-CV) in children and adults in Vietnam. Methods: In this prospective, open-label, single-center, single-arm study, 250 healthy participants aged 9 months to 60 years received a single dose of JE-CV (IMOJEV 1). JE neutralizing antibody titers were assessed at baseline and 28 days after vaccination using the 50% plaque reduction neutralization test (PRNT 50). Safety and reactogenicity were assessed through solicited and unsolicited adverse events. Findings: Seroconversion (titer 10 [1/dil] in participants JE seronegative [titer <10] at baseline [per protocol analysis], or a 4-fold rise from a baseline titer 10) and seroprotection (titer 10 [1/dil]) rates 28 days after vaccination were both 98.5% (132/134) in the per protocol analysis, and 82.4% (201/244) and 98.8% (242/245), respectively, in the full analysis set. Geometric mean titers (GMTs) increased in all age groups from Day 0 to Day 28; Day 28/Day 0 GMT ratios were 55.3 (95% confidence interval [CI] 38.4-79.8), 348 (95% CI 211-572), 296 (95% CI 152-576) and 194 (95% CI 13.1-2870) in those aged 9 months to 4 years, 5-11 years, 12-17 years and 18-60 years, respectively, in the per protocol analysis. There were no safety concerns during the study. Conclusion: A single dose of JE-CV in children and adults aged 9 months to 60 years in Vietnam elicited a protective immune response and was well tolerated with no safety concerns. Registered at www.clinicaltrials.gov (NCT02492165).
Background: A phase III, randomized, double-blind, placebo-controlled clinical study was conducte... more Background: A phase III, randomized, double-blind, placebo-controlled clinical study was conducted in China to assess the efficacy, safety, and immunogenicity of the pentavalent rotavirus vaccine (RotaTeq TM , RV5) among Chinese infants. The efficacy and safety data have been previously reported. This report presents the immunogenicity data of the study. Methods: 4,040 infants aged 6-12 weeks were randomly assigned in a 1:1 ratio to receive 3 oral doses of RV5 or placebo. Trivalent oral poliovirus vaccine (tOPV) and diphtheria, tetanus, and acellular pertussis vaccine (DTaP) were administered in a staggered-use (N = 3,240) or concomitant-use (N = 800) schedule. Immunogenicity of RV5 was evaluated in 800 participants (400 participants from each staggered-and concomitant-use immunogenicity subgroup). Geometric mean titers (GMTs) and seroresponse rates (!3-fold rise from baseline to PD3) were measured for anti-rotavirus IgA in the staggered-and concomitant-use subgroups and measured for serum neutralizing antibodies (SNAs) to human rotavirus serotypes G1, G2, G3, G4, P1A[8] in the staggered-use subgroup. Immune responses to tOPV and DTaP coadministered with RV5 were also evaluated in the concomitant-use immunogenicity subgroup. (ClinicalTrials.gov registry: NCT02062385) Results: The PD3 GMT and seroresponse rate of anti-rotavirus IgA were higher in the RV5 group (82.42 units/mL, 89.4%) compared to the placebo group (0.33 units/mL, 10.1%). Rotavirus type-specific SNA responses were also higher in the RV5 group compared to the placebo group. In the concomitant-use subgroup, the seroprotection rates of anti-poliovirus type 1, 2, 3 in the participants who received RV5 were non-inferior to those who received placebo, and the antibody responses to DTaP antigens were comparable between the two vaccination groups. Conclusions: RV5 was immunogenic in Chinese infants. Immune responses induced by tOPV and DTaP were not affected by the concomitant use of RV5.
Objective To characterize influenza seasonality and identify the best time of the year for vaccin... more Objective To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and southeastern Asia that lie north of the equator. Methods Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao People's Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries. Findings Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao People's Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator. Conclusion Most southern and southeastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.
Bulletin of The World Health Organization, Feb 1, 2011
is a low-income country with an estimated total population of 87 million. According to data from ... more is a low-income country with an estimated total population of 87 million. According to data from the United Nations Children's Fund, from 2003 to 2008 the average annual number of births in the country was 1 494 000 and the average annual prevalence of low birth weight was 7%. In 2008, the maternal mortality ratio was 150 per Abstracts in ,عريب 中文, Français, Pусский and Español at the end of each article. Objective To examine the association between gestational weight gain and maternal body mass index (BMI) among Vietnamese women and the risk of delivering an infant too small or too large for gestational age. Methods A prospective health-facility-based study of 2989 pregnant Vietnamese women was conducted in the city of Nha Trang in 2007-2008. Cubic logistic regression was used to investigate the association of interest. Infants were classified into weight-forgestational-age categories according to weight centiles for the Asian population. Gestational age was based on the date of last menstrual period and adjusted by the results of first-trimester ultrasound. Findings BMI was low (< 18.5), normal (18.5-22.9) and high (≥ 23.0) in 26.1%, 65.4% and 8.5% of the women, respectively. In each of these BMI categories, the percentage of women who delivered infants too small for gestational age was 18.1, 10.0 and 9.4, respectively, and the mean gestational weight gain was 12.5 kg (standard deviation, SD: ± 3.6), 12.2 kg (SD: ± 3.8) and 11.5 kg (SD: ± 4.7), respectively. Among women with low BMI, the risk of delivering an infant too small for gestational age ranged from approximately 40% if the gestational weight gain was < 5 kg to 20% if it was 5-10 kg. Conclusion Having a low BMI, commonly found in Viet Nam, puts women at risk of delivering an infant too small for gestational age, especially when total maternal gestational weight gain is < 10 kg.
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