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Gorar ZA, Butt ZA. Impact of hepatitis B birth dose on immune response in Pakistani children: an open-label, non-inferiority randomized controlled trial, implications for achieving SDG target. Infect Dis (Lond) 2024; 56:1-10. [PMID: 37712585 DOI: 10.1080/23744235.2023.2258208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 09/16/2023] Open
Abstract
BACKGROUND Despite presence of hyperendemic areas, the national immunisation schedule in Pakistan does not include a hepatitis B birth dose, placing newborns at an additional risk of acquiring hepatitis B. This study aimed to assess the impact of adding hepatitis B birth dose in existing national vaccination schedule. METHODS An open label, randomised controlled non-inferiority trial enrolled 296 healthy near-term mothers to intervention and control groups. Newborns in the intervention group received a hepatitis B birth dose along with routine immunisation vaccines, while control group newborns received vaccinations under the national schedule. Seroprotection was measured and compared at birth and 8 weeks after administering the third dose of pentavalent vaccine. The risk ratio of seroprotection was computed and compared with the delta value set at 5%. RESULTS The study found that 95.8% of infants in the intervention group achieved seroprotection, which was significantly higher than the control group's 58.7%. The difference in risk ratio of seroprotection was 1.62 (CI95: 1.37-1.93), with the upper limit of the CI below the delta margin, confirming non-inferiority. The time interval between birth and the first hepatitis B immunisation shot was a predictor of seroprotection, with an odds ratio of 1.79 (CI95: 1.01-2.9). CONCLUSION Our study indicates that adding a hepatitis B birth dose to the immunisation schedule in Pakistan is non-inferior to the existing one. This can also contribute towards Pakistan's achievement of the SDG target of reducing hepatitis B surface antigen seroprevalence in children under 5 years of age. TRIAL REGISTRATION NUMBER NCT04870021.
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Affiliation(s)
| | - Zahid Ahmad Butt
- School of Public Health Sciences, University of Waterloo, Waterloo, Canada
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Miyano S, Pathammavong C, Ichimura Y, Sugiyama M, Phounphenghack K, Tengbriacheu C, Khamphaphongphane B, Nouanthong P, Franzel L, Yang TU, Raaijimakers H, Ota T, Funato M, Komada K, Hachiya M. Prevalence of hepatitis B and C virus infections in Lao People's Democratic Republic: The first national population-based cross-sectional survey. PLoS One 2022; 17:e0278933. [PMID: 36584043 PMCID: PMC9803141 DOI: 10.1371/journal.pone.0278933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/23/2022] [Indexed: 12/31/2022] Open
Abstract
Population-based seroprevalence of chronic hepatitis B and C infections has not been examined in Lao People's Democratic Republic (PDR). Therefore, this study aimed to estimate the seroprevalence of these infections in the general population of Lao PDR and perform subgroup analysis. A nationwide seroprevalence survey was conducted in Lao PDR in June 2019 using the multistage cluster sampling method. Dried blood spot samples were collected onto WhatmanTM 903 filter paper by finger prick. A chemiluminescent microparticle immunoassay was used to measure the levels of hepatitis B surface antigen (HBsAg) and hepatitis C antibody (HCV-Ab). Samples in which the HBsAg level was above 0.05 IU/ml and HCV-Ab was above the signal/cutoff ratio of 1.0 were considered positive based on comparisons with the relative light unit value of a calibration sample. A total of 1,927 samples (male: 47.3%, mean age: 23.0 years) were included in the analysis. The prevalence was estimated to be 4.2% (95% confidence interval [CI]: 2.7-6.3) for HBsAg and 1.6% (95% CI: 0.5-5.3) for HCV-Ab. Multivariable analysis revealed that those aged 20-24 years (adjusted odds ratio (AOR): 2.3, 95% CI: 1.1-4.6), those aged 25-29 years (AOR: 2.7, 95% CI: 1.3-5.6), those from the Northern region (AOR: 2.8, 95% CI: 1.2-6.6), and those who were Khmu (AOR: 3.6, 95% CI: 2.0-6.8) or Hmong (AOR: 5.0, 95% CI: 3.3-7.5) were significantly more likely to be positive for HBsAg. Although there were no statistically significant differences in the HCV-Ab prevalence according to each variable, males (2.9%, 95% CI: 0.7-10.7), those aged ≥40 years (6.1%, 95% CI: 2.1-16.8), and those from the Southern region (3.3%, 95% CI: 0.6-15.3) tended to have a higher prevalence. This novel population-based survey found differences in the prevalence of chronic hepatitis B and hepatitis C virus infections in Lao PDR according to sex, age group, region, and ethnicity; however, the results of this study should be confirmed in future studies, and relevant responses tailored for each target also need to be determined to control the transmission of hepatitis B and C infections.
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Affiliation(s)
- Shinsuke Miyano
- Bureau of International Health Cooperation and WHO Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
- * E-mail:
| | - Chansay Pathammavong
- National Immunization Program, Mother and Child Health Center, Ministry of Health, Lao People’s Democratic Republic (Lao PDR), Vientiane Capital, Lao PDR
| | - Yasunori Ichimura
- Bureau of International Health Cooperation and WHO Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Masaya Sugiyama
- Genome Medical Science Project, The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikwa, Chiba, Japan
| | - Kongxay Phounphenghack
- National Immunization Program, Mother and Child Health Center, Ministry of Health, Lao People’s Democratic Republic (Lao PDR), Vientiane Capital, Lao PDR
| | | | | | - Phonethipsavanh Nouanthong
- Institute Pasteur du Laos, National Immunization Technical Advisory Group, Ministry of Health, Vientiane Capital, Lao PDR
| | - Lauren Franzel
- Vaccine-Preventable Diseases and Immunization Team, WHO Lao PDR, Vientiane Capital, Lao PDR
| | - Tae Un Yang
- Vaccine-Preventable Diseases and Immunization Team, WHO Lao PDR, Vientiane Capital, Lao PDR
| | | | - Tomomi Ota
- Bureau of International Health Cooperation and WHO Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Masafumi Funato
- Bureau of International Health Cooperation and WHO Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Kenichi Komada
- Bureau of International Health Cooperation and WHO Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Masahiko Hachiya
- Bureau of International Health Cooperation and WHO Collaborating Center for Health Systems Development, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
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Hefele L, Lai J, Vilivong K, Bounkhoun T, Chanthaluanglath V, Chanthongthip A, Balloch A, Black AP, Hübschen JM, Russell FM, Muller CP. Haemophilus influenzae serotype b seroprevalence in central Lao PDR before and after vaccine introduction. PLoS One 2022; 17:e0274558. [PMID: 36107979 PMCID: PMC9477263 DOI: 10.1371/journal.pone.0274558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 08/31/2022] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Vaccination has dramatically reduced invasive Haemophilus influenzae type b (Hib) disease worldwide. Hib vaccination was introduced in the Lao PDR in 2009, as part of the pentavalent vaccine. To contribute to the understanding of the epidemiology of Hib in Lao PDR and the protection levels before and after the introduction of the vaccination, we tested serum samples from existing cohorts of vaccine age-eligible children and unvaccinated adolescents for antibodies against Hib. METHODS Serum samples from 296 adolescents born before vaccine introduction and from 1017 children under 5 years (vaccinated and unvaccinated) were tested for anti-Hib antibodies by ELISA. Bivariate analyses were performed to investigate factors associated with long-term protection. RESULTS The vast majority of all participants showed evidence of short- (42.7%) or long-term (56.1%) protection against Hib. Almost all of the unvaccinated adolescents had antibody titers indicating short-term protection and almost half (45.6%) were long-term protected. Nearly all children (>99.0%) were at least short-term protected, even those that were unvaccinated or whose vaccination status was unknown. Among vaccinated children, participants vaccinated more than 1 or 2 years ago and with a mid-upper arm circumference z-score < -2 were less likely to be long-term protected. DISCUSSION Nearly all adolescents born before the introduction of Hib vaccination in the Lao PDR had antibody titers corresponding to at least short-term protection, indicating a high burden of Hib disease at that time. After vaccine introduction, all but four children (>99%) showed at least short-term protection. Possible explanations for the proportion of protected, yet apparently unvaccinated children, may be past infections, cross-reacting antibodies or faulty vaccination documentation. Our results highlight the need for robust surveillance and reporting of invasive Hib disease to determine the burden of disease despite vaccination.
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Affiliation(s)
- Lisa Hefele
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Jana Lai
- New Vaccines, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
- National Centre for Epidemiology and Population Health, Acton, ACT, Australia
| | - Keoudomphone Vilivong
- Lao-Oxford Mahosot Hospital Wellcome Trust Research Unit, Vientiane Capital, Lao PDR
| | - Toukta Bounkhoun
- Lao-Oxford Mahosot Hospital Wellcome Trust Research Unit, Vientiane Capital, Lao PDR
| | | | - Anisone Chanthongthip
- Lao-Oxford Mahosot Hospital Wellcome Trust Research Unit, Vientiane Capital, Lao PDR
| | - Anne Balloch
- New Vaccines, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
| | | | - Judith M. Hübschen
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Fiona M. Russell
- Department of Paediatrics, The University of Melbourne, Victoria, Australia
- Asia-Pacific Health Research, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
| | - Claude P. Muller
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
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Susceptibility to Vaccine-Preventable Diseases in Four Districts of Xaysomboun Province, Lao People’s Democratic Republic. Vaccines (Basel) 2022; 10:vaccines10030463. [PMID: 35335095 PMCID: PMC8952207 DOI: 10.3390/vaccines10030463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 11/24/2022] Open
Abstract
Xaysomboun province has some of the lowest health indicators in Lao People’s Democratic Republic (PDR). This cross-sectional study aimed to determine the vaccination, susceptibility and exposure status of the population to hepatitis B virus (HBV), measles, rubella, and tetanus. Participants aged 5 years and older were randomly selected from four districts. From each enrolled participant, demographic data and 5 mL of blood sample were taken. HBV surface antigen (HBsAg) and antibodies against HBV, measles, rubella, and tetanus were detected by ELISA. A total of 363 participants (age 5 to 80 years) were included. HBV exposure, as determined by anti-HBV core (anti-HBc) antibodies, was 56.2% overall, and was significantly higher among those aged ≥21 years (78.1%). HBsAg was detected in 9.4% overall and increased to 20% in ages 31–40 years. Only 13.8% of participants had serology indicative of vaccination (anti-HBs positive, anti-HBc negative). Seroprotection against measles was 74.6% overall but only 41.7% in children aged 5–10 years. Anti-rubella IgG was 94.2% overall and high in all age groups. Tetanus seroprevalence was only 47.4% overall but significantly higher in females aged 31–40 (75.6%). We suggest strengthening of routine and booster HBV, measles, and tetanus vaccine coverage in Xaysomboun province.
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Nouanthong P, Hefele L, Keokhamphue J, Sorrasin V, Khounvisith V, Souksakhone C, Jutavijittum P, Muller CP, Black AP, Hübschen JM. Analyses of blood donor samples from eight provinces in Lao PDR suggest considerable variation concerning HBV exposure and carriage. PLoS One 2021; 16:e0259814. [PMID: 34898623 PMCID: PMC8668104 DOI: 10.1371/journal.pone.0259814] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 10/26/2021] [Indexed: 01/07/2023] Open
Abstract
Introduction Hepatitis B is endemic in Lao PDR and about 9% of the adult population is chronically infected. In this study, we investigated regional, occupational, age and sex-related differences in hepatitis B epidemiology in Lao blood donors. Methods 5017 voluntary blood donors from 8 different provinces were tested for hepatitis B markers by ELISA. Predictors for the prevalence of hepatitis B surface antigen (HBsAg) and antibodies against the core antigen (anti-HBc) were assessed by bivariate and multivariable analyses. Results In total, 41% of the participants were positive for anti-HBc; the HBsAg prevalence was estimated at 6.9% among all participants (9.2% among first-time donors and 3.9% among repeat donors). Among first-time donors, HBsAg positivity was associated independently with being male (p<0.001), being from the North (p<0.001) and being soldier (p<0.001). Participants were more likely to be anti-HBc positive when they were male (p<0.001), from the Northern provinces (p<0.001) and older than 20 years (p<0.01). Conclusion In conclusion, our study confirmed an overall high HBsAg and anti-HBc prevalence in Lao PDR, albeit with considerable regional variation. The identification of a sizeable number of HBsAg positives among repeat donors warrants a thorough investigation of current blood screening, record keeping, donor identification and counselling practises.
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Affiliation(s)
| | - Lisa Hefele
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Jerapha Keokhamphue
- National Blood Transfusion Center, Lao Red Cross, Rue Phai Nam, Vientiane, Lao PDR
| | - Vonhphet Sorrasin
- National Blood Transfusion Center, Lao Red Cross, Rue Phai Nam, Vientiane, Lao PDR
| | - Vilaysone Khounvisith
- Lao-Lux Laboratory, Institut Pasteur du Laos, Ban Kao-Gnot, Sisattanak District, Vientiane, Lao PDR
| | | | - Prapan Jutavijittum
- Department of Pathology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Claude P. Muller
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Antony P. Black
- Lao-Lux Laboratory, Institut Pasteur du Laos, Ban Kao-Gnot, Sisattanak District, Vientiane, Lao PDR
| | - Judith M. Hübschen
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
- * E-mail:
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Pasharawipas T. Different Aspects Concerning Viral Infection and the Role of MHC Molecules in Viral Prevention. Open Microbiol J 2021. [DOI: 10.2174/1874285802115010072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Major Histocompatibility Complex (MHC) molecules play a crucial role in inducing an adaptive immune response. T-cell epitopes require compatible MHC molecules to form MHC-peptide Complexes (pMHC) that activate the T-cell Receptors (TCR) of T-lymphocyte clones. MHCs are polymorphic molecules with wide varieties of gene alleles. There are two classes of MHC molecules, class I and II. Both classes have three classical loci HLA-A, -B, and –C are present in class I and HLA-DP, -DQ, and -DR in class II. To induce a compatible T-lymphocyte clone, the T-cell epitope requires the association of the compatible MHC molecule to form pMHC. Each MHC variant possesses a different groove that is capable of binding a different range of antigenic epitopes. Without the compatible MHC molecule, a T cell clone cannot be activated by a particular viral epitope. With the aim of preventing viral transmission, the efficiency of a viral vaccine is related to the existence of specific MHC alleles in the individual. This article proposes the roles of the MHC molecule to prevent viral infection. In addition, the association of the viral receptor molecule with the viral infection will also be discussed.
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7
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Hefele L, Xaydalasouk K, Kleine D, Homsana A, Xayavong D, Syphan S, Hübschen JM, Muller CP, Black AP. Seroprevalence of measles and rubella antibodies in vaccinated and unvaccinated infants in the Lao People's Democratic Republic. Int J Infect Dis 2021; 108:524-530. [PMID: 34119678 DOI: 10.1016/j.ijid.2021.06.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Even though measles vaccination was introduced in the Lao PDR in 1984, coverage rates remain consistently low and outbreaks continue to occur frequently. This study was performed to investigate the seroprevalence of measles and rubella antibodies in vaccinated and unvaccinated children from Central Lao PDR. METHODS Antibody titres of 1090 children aged 8-29 months who were vaccinated at different levels of the health care system were assessed by ELISA. Bivariate and multivariable analyses were performed to identify factors affecting seropositivity against measles and rubella. RESULTS Among the vaccinated children, 67.5% in Vientiane Province and 76.4% in Bolikhamxay Province were double positive/borderline for measles and rubella IgG. A high proportion of unvaccinated children at both study sites (24.4% and 38.4%) were positive/borderline for measles and/or rubella. Time since vaccination <180 days, more than two siblings, and a mother who is a farmer/labourer were negatively associated with seropositivity. CONCLUSIONS A high prevalence of measles and rubella antibodies was found in unvaccinated children, indicating widespread circulation of both viruses and underreporting of cases. The high proportion of vaccinated children still susceptible to measles suggests problems with vaccine immunogenicity, emphasizing the need for regular evaluations of vaccine efficacy and management.
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Affiliation(s)
- Lisa Hefele
- Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | | | - Daria Kleine
- Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg; Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Laos
| | | | | | | | | | - Claude P Muller
- Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Antony P Black
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Laos.
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Kitamura T, Bouakhasith V, Phounphenghack K, Pathammavong C, Xeuatvongsa A, Kobayashi A, Norizuki M, Okabayashi H, Miyano S, Mori Y, Takeda M, Sugiyama M, Mizokami M, Machida M, Hachiya M. Vaccine temperature management in Lao People's Democratic Republic: A nationwide cross-sectional study. Heliyon 2021; 7:e07342. [PMID: 34307926 PMCID: PMC8258653 DOI: 10.1016/j.heliyon.2021.e07342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 05/05/2021] [Accepted: 06/14/2021] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE The objective of the study was to evaluate the duration and frequency of vaccine exposure to suboptimal temperatures during transit from the central vaccine storage in the capital to health centers in Lao PDR. METHODS Temperature data loggers traveled from the capital to the health centre storages (146) with the vaccines to monitor the vaccine temperature nationwide. One health centre per district was selected using a simple random sampling method for the first round of temperature monitoring. One health centre was selected from every forty-nine high risk districts monitor the trend of vaccine temperature at the health centre storage and during outreach sessions in several districts. Vaccines and temperature data loggers were transported using the normal vaccination transportation. FINDINGS Overall, the vaccines were exposed to temperatures >8 °C for an average of 1648 min, equivalent to 9.0% of the observational period, and to temperatures <0 °C for an average of 184 min, equivalent to 1.35% of the study period. The proportion of exposure to temperatures >8 °C was the highest during the transit from the capital to the province. The proportion of exposure to temperatures <0 °C was the highest during storage at district level. Examined by region, vaccines in the northern provinces had higher risk of exposure to temperatures >8 °C; however, the risk of exposure to temperatures <0 °C was scattered nationwide. Moreover, some health centers showed fluctuations in storage temperature. CONCLUSIONS Challenges associated with cold chain management, and the resulting deterioration of vaccines, might account for outbreaks of vaccine-preventable diseases. The government should examine and invest in suitable technologies and approaches to ensure consistency in cold chain management.
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Affiliation(s)
- Tomomi Kitamura
- National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku, Tokyo, 1628655 Japan
| | | | | | | | | | - Akiko Kobayashi
- School of International Health, Graduate School of Medicine, University of Tokyo, Tokyo, 113-8654, Japan
| | - Masataro Norizuki
- National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku, Tokyo, 1628655 Japan
| | - Hironori Okabayashi
- National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku, Tokyo, 1628655 Japan
| | - Shinsuke Miyano
- National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku, Tokyo, 1628655 Japan
| | - Yoshio Mori
- National Institute of Infectious Diseases, Murayama Branch, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan
| | - Makoto Takeda
- National Institute of Infectious Diseases, Murayama Branch, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan
| | - Masaya Sugiyama
- Genome Medical Sciences Project, National Center for Global Health and Medicine, 1-7-1 Kohnodai, Ichikawa, Chiba, 272-8516, Japan
| | - Masashi Mizokami
- Genome Medical Sciences Project, National Center for Global Health and Medicine, 1-7-1 Kohnodai, Ichikawa, Chiba, 272-8516, Japan
| | - Munehito Machida
- Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 13-1 Takaramachi, Ishikawa, Kanazawa, 9208640, Japan
| | - Masahiko Hachiya
- National Center for Global Health and Medicine, 1-21-1 Toyama Shinjuku, Tokyo, 1628655 Japan
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Xaydalasouk K, Sayasinh K, Hübschen JM, Khounvisith V, Keomany S, Muller CP, Black AP. Age-stratified seroprevalence of vaccine-preventable infectious disease in Saravan, Southern Lao People's Democratic Republic. Int J Infect Dis 2021; 107:25-30. [PMID: 33864919 DOI: 10.1016/j.ijid.2021.04.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 12/09/2022] Open
Abstract
BACKGROUND Lao People's Democratic Republic has frequent outbreaks of vaccine-preventable diseases (VPD). This study aimed to determine susceptibility and exposure to VPD in Saravan, a rural province with high ethnic diversity and some of the poorest health indicators nationwide. METHODS Patients from three district hospitals and one provincial hospital were enrolled. Serum was tested by ELISA for IgG against hepatitis B virus (HBV), tetanus, diphtheria, measles, and rubella. RESULTS The study enrolled 2463 participants aged 5-90 years. Exposure to HBV was 33.2% and increased with age up to 62.4% of those aged >50 years. HBV surface antigen prevalence was 5.7% in males and 2.4% in females; 9.9% had serology compatible with vaccination. Seroprevalence of protective anti-tetanus antibodies was 46.3% overall. Protective anti-diphtheria seroprevalence was 40.5%. Anti-measles seroprevalence increased from 16.7% in those aged 5-10 years to 97.7% in those aged >50 years. Anti-rubella seroprevalence was 93.0% overall. There were differences in seroprevalences between sex, districts and ethnicity. CONCLUSIONS Routine infant vaccination needs strengthening in order to close the immunity gaps. High burden of HBV infection should be addressed by increasing birth dose vaccine coverage. Regional and ethnic differences need to be investigated to enable a targeted approach to vaccination.
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Affiliation(s)
| | - Kong Sayasinh
- Saravan Provincial Hospital, 15A, Phonekeo Village Saravan, Laos
| | | | | | - Sommai Keomany
- Saravan Provincial Hospital, 15A, Phonekeo Village Saravan, Laos
| | | | - Antony P Black
- Institut Pasteur du Laos, Rue Samsenthai, Vientiane, Laos.
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Abstract
Laos is a landlocked country in South East Asia, ranking fifth for primary liver cancer incidence worldwide. Risk factors that might explain this worrying situation are poorly known. We conducted a review of the literature concerning the etiologies of terminal liver diseases in Laos. A double infectious burden with hepatitis B and C viruses and the liver fluke Opisthorchis viverrini seems to be the main cause of the high liver cancer incidence. Moreover, it was also suggested that mutagenic substances frequently found in tobacco, alcoholic beverages, fermented fish, and mold-contaminated cereals or nuts, which are all substances heavily consumed by Lao people, lead to the accumulation of DNA mutations in the liver cell genome causing tumor processes. However, the respective proportions of liver cancer cases attributable to each category of infections and substances consumed, as well as the histological nature of the neoplasia are still not precisely documented in Laos. The international medical and scientific communities as well as public health stakeholders should urgently consider the alarming situation of liver health in Laos to stimulate both research and subsequent implementation of prevention policies.
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Hefele L, Syphan S, Xayavong D, Homsana A, Kleine D, Chanthavilay P, Nouanthong P, Xaydalasouk K, Phathammavong O, Billamay S, Xeuatvongsa A, Reinharz D, Muller CP, Black AP. Seroprotection at Different Levels of the Healthcare System After Routine Vaccination With Diphtheria-Tetanus-Pertussis whole cell-Hepatitis B-Haemophilus influenzae Type B in Lao People's Democratic Republic. Clin Infect Dis 2020; 69:2136-2144. [PMID: 30778522 PMCID: PMC6880335 DOI: 10.1093/cid/ciz143] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/13/2019] [Indexed: 01/23/2023] Open
Abstract
Background The Lao People’s Democratic Republic continues to sustain a considerable burden of vaccine-preventable diseases because of incomplete vaccine coverage and weak vaccine responses. We have assessed seroconversion after routine vaccination with the pentavalent vaccine to capture weaknesses of vaccine management at the different levels of the healthcare system. Methods A total of 1151 children (aged 8–28 months) with 3 documented doses of the pentavalent vaccine delivered at central hospitals in Vientiane and the provincial hospital, 3 district hospitals, and 10 health centers in Bolikhamxay province were enrolled. Sociodemographic information was collected with a standardized questionnaire. Serum samples were analyzed for antibodies against vaccine components, and bivariate and multivariable analyses were performed to identify risk factors for low vaccine responses. Results Seroprotection rates at the provincial, district, and health center level were as high as in central hospitals, but seroprotection rates in areas covered by remote health centers were significantly lower. Protective levels also rapidly decreased with age at sampling. Seroprotection rates in Bolikhamxay against the different components reached 70%–77% and were up to 20% higher than in previous studies in the same region; 18.8% more children received the hepatitis B vaccine birth dose and the hepatitis B virus infection rate was 4 times lower. Conclusions Vaccine immunogenicity has dramatically improved in a central province, likely due to training and investment in the cold chain. Nevertheless, there remains a need to focus on the “last mile” in remote areas were most children are vaccinated through outreach activities.
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Affiliation(s)
- Lisa Hefele
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People's Democratic Republic.,Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Sengdavanh Syphan
- Institut de la Francophonie pour la Médecine Tropicale, Vientiane, Lao People's Democratic Republic
| | - Dalouny Xayavong
- Institut de la Francophonie pour la Médecine Tropicale, Vientiane, Lao People's Democratic Republic
| | - Anousin Homsana
- Institut de la Francophonie pour la Médecine Tropicale, Vientiane, Lao People's Democratic Republic
| | - Daria Kleine
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People's Democratic Republic.,Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg
| | - Phetsavanh Chanthavilay
- Institut de la Francophonie pour la Médecine Tropicale, Vientiane, Lao People's Democratic Republic
| | | | - Kinnaly Xaydalasouk
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People's Democratic Republic
| | | | - Somxay Billamay
- Children Hospital, Vientiane, Lao People's Democratic Republic
| | - Anonh Xeuatvongsa
- Expanded Programme on Immunisation, Vientiane, Lao People's Democratic Republic
| | - Daniel Reinharz
- Institut de la Francophonie pour la Médecine Tropicale, Vientiane, Lao People's Democratic Republic
| | - Claude P Muller
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao People's Democratic Republic.,Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Grand-Duchy of Luxembourg.,Laboratoire national de santé, Dudelange, Grand-Duchy of Luxembourg
| | - Antony P Black
- Institut de la Francophonie pour la Médecine Tropicale, Vientiane, Lao People's Democratic Republic
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12
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Rattanavong S, Dubot-Pérès A, Mayxay M, Vongsouvath M, Lee SJ, Cappelle J, Newton PN, Parker DM. Spatial epidemiology of Japanese encephalitis virus and other infections of the central nervous system infections in Lao PDR (2003-2011): A retrospective analysis. PLoS Negl Trop Dis 2020; 14:e0008333. [PMID: 32453806 PMCID: PMC7274481 DOI: 10.1371/journal.pntd.0008333] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 06/05/2020] [Accepted: 04/28/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Central nervous system (CNS) infections are important contributors to morbidity and mortality and the causative agents for ~50% patients are never identified. The causative agents of some CNS infections have distinct spatial and temporal patterns. METHODOLOGY/PRINCIPAL FINDINGS Here we present the results of a spatial epidemiological and ecological analysis of CNS infections in Lao PDR (2003-2011). The data came from hospitalizations for suspected CNS infection at Mahosot Hospital in Vientiane. Out of 1,065 patients, 450 were assigned a confirmed diagnosis. While many communities in Lao PDR are in rural and remote locations, most patients in these data came from villages along major roads. Japanese encephalitis virus ((JEV); n = 94) and Cryptococcus spp. (n = 70) were the most common infections. JEV infections peaked in the rainy season and JEV patients came from villages with higher surface flooding during the same month as admission. JEV infections were spatially dispersed throughout rural areas and were most common in children. Cryptococcus spp. infections clustered near Vientiane (an urban area) and among adults. CONCLUSIONS/SIGNIFICANCE The spatial and temporal patterns identified in this analysis are related to complex environmental, social, and geographic factors. For example, JEV infected patients came from locations with environmental conditions (surface water) that are suitable to support larger mosquito vector populations. Most patients in these data came from villages that are near major roads; likely the result of geographic and financial access to healthcare and also indicating that CNS diseases are underestimated in the region (especially from more remote areas). As Lao PDR is undergoing major developmental and environmental changes, the space-time distributions of the causative agents of CNS infection will also likely change. There is a major need for increased diagnostic abilities; increased access to healthcare, especially for rural populations; and for increased surveillance throughout the nation.
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Affiliation(s)
- Sayaphet Rattanavong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Audrey Dubot-Pérès
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Unité des Virus Émergents (UVE: Aix-Marseille Univ–IRD 190 –Inserm 1207 –IHU Méditerranée Infection), Marseille, France
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Institute of Research and Education Development, University of Health Sciences, Vientiane, Lao PDR
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Sue J. Lee
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Julien Cappelle
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- CIRAD, UMR ASTRE, F-34398, Montpellier, France
- UMR ASTRE, CIRAD, INRA, Montpellier University, Montpellier, France
- UMR EpiA, INRA, VetAgro Sup, Marcy l’Etoile, France
| | - Paul N. Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Daniel M. Parker
- Department of Population Health and Disease Prevention, University of California, Irvine, United States of America
- Department of Epidemiology, School of Medicine, University of California, Irvine, United States of America
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13
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Pertussis in Lao PDR: Seroprevalence and disease. Int J Infect Dis 2020; 95:282-287. [PMID: 32278108 DOI: 10.1016/j.ijid.2020.03.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES Pertussis is a debilitating vaccine-preventable infection. The aim of this study was to determine susceptibility and exposure to pertussis in Lao PDR in different age groups and subpopulations. METHODS A total 3072 serum samples were obtained from different cohorts: children with documented vaccination, pre-schoolers, schoolchildren, blood donors, healthcare workers (HCWs), and pregnant women and paired cord blood. Samples were tested for anti-pertussis toxin IgG antibodies. A history of Bordetella pertussis exposure was defined according to antibody titres. Four hundred and seventy-five throat swabs and nasopharyngeal aspirates were analysed by PCR for the presence of B. pertussis in symptomatic children at the Children's Hospital in Vientiane. RESULTS Overall pertussis seroprevalence was 57.5%. The prevalence of titres indicating acute infection or recent vaccination or infection/vaccination within the last 12 months ranged from 7.4% (100/1356) in adults to 21.4% (25/117) in pre-schoolers (age 1-5 years). B. pertussis was detected in 1.05% (5/475) of children with respiratory symptoms in Vientiane Capital. CONCLUSIONS It is suggested that routine childhood vaccination, in particular outreach, as well as vaccination of HCWs should be strengthened. A childhood booster and vaccination of pregnant mothers should be considered. There is also a need to improve reporting and to introduce pertussis testing in at least one central facility.
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14
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Di Lello FA, Blejer J, Alter A, Bartoli S, Vargas F, Ruiz R, Galli C, Blanco S, Gallego S, Fernández R, Martínez AP, Flichman DM. Hepatitis B surface antibodies seroprevalence among people born before and after implementation of universal HBV vaccination. Vaccine 2020; 38:2678-2682. [PMID: 32061386 DOI: 10.1016/j.vaccine.2020.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/22/2020] [Accepted: 02/05/2020] [Indexed: 12/16/2022]
Abstract
Universal vaccination is the most effective strategy to control hepatitis B virus (HBV) infection. In Argentina, vaccination against HBV was incorporated in year 2000 for newborns and in 2003 for 11 years old children. However, there is a paucity of data about protection levels against HBV infection. The aim of this work was to determine the prevalence of seroprotective anti-HBs antibodies (aHBs) in Argentina. Serum samples negative for HBsAg and anti-HBc from 132 children born after year 2000 and 762 blood donors, older than 18 years, from five centers across the country, were analyzed for aHBs. Titers ≥10 mIU/mL were observed in 74/132 children (56.1%) and 336/762 (44.1%) in blood donors. The median age for blood donors was 33.9 (23-43); from them, 210 (27.6%) were born after 1992 and, therefore, were catch-up by vaccine implementation at 11 years old age. Donors born in 1992 or before showed a significantly lower frequency of protection (32.2%) compared to donors born after 1992 (75.2%), p < 0.0001. In addition, significant differences were observed in the status of seroprotection between different participating centers (p = 0.024). Implementation of HBV vaccine in 2000 and 2003 implied an overall increase of the aHBs seroprotective rates, with a particularly adequate response in children vaccinated at 11 years old age. The observed results suggest that population born in 1992 or before is currently the most susceptible. Consequently, it would be advisable to become aware of the risk of transmission in this age group and to stress this population vaccination campaigns.
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Affiliation(s)
- Federico A Di Lello
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular (IBaViM), Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
| | - Jorgelina Blejer
- Fundación Hemocentro, Ciudad Autónoma de Buenos Aires, Argentina
| | - Adriana Alter
- Fundación Hemocentro, Ciudad Autónoma de Buenos Aires, Argentina
| | - Sonia Bartoli
- Centro Regional de Hemoterapia Jujuy, San Salvador de Jujuy, Jujuy, Argentina
| | - Fabiana Vargas
- Centro Regional de Hemoterapia de Mendoza, Mendoza, Mendoza, Argentina
| | - Rosángela Ruiz
- Hospital Regional Rio Grande, Rio Grande, Tierra del Fuego, Argentina
| | - Claudio Galli
- Hospital Regional Rio Grande, Rio Grande, Tierra del Fuego, Argentina
| | - Sebastián Blanco
- Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Córdoba, Argentina; Fundación Banco Central de Sangre, Córdoba, Córdoba, Argentina
| | - Sandra Gallego
- Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Córdoba, Argentina; Fundación Banco Central de Sangre, Córdoba, Córdoba, Argentina
| | | | - Alfredo P Martínez
- Sección Virología, Centro de Educación Médica e Investigaciones Clínicas Norberto Quirno "CEMIC", Ciudad Autónoma de Buenos Aires, Argentina
| | - Diego M Flichman
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina; Instituto de Investigaciones Biomédicas en Retrovirus y Síndrome de Inmunodeficiencia Adquirida (INBIRS)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
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15
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Hefele L, Vannachone S, Khounvisith V, Nouanthong P, Sayasone S, Kounnavong S, Chanthavilay P, Muller CP, Black AP. Lasting benefit of infant hepatitis B vaccination in adolescents in the Lao People's Democratic Republic. Int J Infect Dis 2020; 93:217-223. [PMID: 32014602 DOI: 10.1016/j.ijid.2020.01.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/25/2020] [Accepted: 01/28/2020] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVES Hepatitis B is endemic in Lao PDR with 8-10% of the adult population being chronically infected. We investigated the impact of hepatitis B vaccination on infection in adolescents born shortly before and after the introduction of the vaccine in 2001. METHODS 779 students from Vientiane Capital and Bolikhamxay province were tested for HBV markers by ELISA. Socio-demographic information was collected with a standardized questionnaire. Predictors/risk factors for seroprotection or exposure to hepatitis B infection were assessed by bivariate and multivariable analyses. RESULTS The prevalence of a serological vaccination profile increased significantly after the introduction of the vaccine (13.2%-21.9%, p < 0.05, in Vientiane; 3.0%-19.7%, p < 0.001, in Bolikhamxay), which translated into at least a 2-times lower prevalence of past infection. In logistic regression, older students in Bolikhamxay were less likely to be vaccinated and more likely to have been infected by HBV in the past. CONCLUSION Even though this study documented a sizable and lasting reduction in past hepatitis B infections in adolescents born after the introduction of infant hepatitis B vaccination, the overall levels of protective anti-HBs were low and warrant at least the introduction of a booster for adolescents. Furthermore, we suggest improving the coverage of the hepatitis B birth dose.
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Affiliation(s)
- Lisa Hefele
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao Democratic People's Republic; Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg.
| | | | - Vilaysone Khounvisith
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao Democratic People's Republic
| | | | - Somphou Sayasone
- Lao Tropical and Public Health Institute, Vientiane, Lao Democratic People's Republic
| | - Sengchang Kounnavong
- Lao Tropical and Public Health Institute, Vientiane, Lao Democratic People's Republic
| | | | - Claude P Muller
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao Democratic People's Republic; Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Antony P Black
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao Democratic People's Republic
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16
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Pauly M, Sayasinh K, Muller CP, Sayasone S, Black AP. High prevalence of helminth infections in mother-child pairs from three central provinces of Lao People's Democratic Republic. Parasite Epidemiol Control 2019; 7:e00122. [PMID: 31872091 PMCID: PMC6911889 DOI: 10.1016/j.parepi.2019.e00122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/30/2019] [Accepted: 10/27/2019] [Indexed: 11/16/2022] Open
Abstract
In Southeast Asia, the large majority of the population remains affected by parasitic worms despite longstanding mass treatment and health education campaigns. Soil-transmitted helminths and also the fish-borne liver fluke negatively affect development during early childhood. Here, the prevalence of helminth infections in stool samples of 610 mother-child pairs from Khammouane, Bolikhamxay and Vientiane provinces in Lao People's Democratic Republic was determined by formalin-ethyl acetate concentration technique. Overall, 15.1% of the children and 46.9% of the mothers were positive for at least one helminth species. Helminth detection rates varied significantly by province with the highest prevelance in Khammouane and the lowest in Bolikhamxay province. Mothers that were positive for soil-transmitted helminths were significantly more likely to have children positive for the same helminth species (p < 0.01) but this was not the case for the liver fluke Opisthorchis viverrini. A protective effect of breastfeeding against soil-transmitted helminths was revealed. Our data reconfirm the generally high helminth burden among mother-child pairs who likely share a number of risky lifestyle behaviors also with other family members. To reduce maternal burden of helminths, we propose that anti-helmintic treatment of women of childbearing age and of mothers during postnatal care should be included in the national strategy.
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Affiliation(s)
- Maude Pauly
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
| | - Kong Sayasinh
- Lao Tropical and Public Health Institute, Vientiane, Lao Democratic People's Republic.,Lao-Lux-Laboratory, Institute Pasteur Du Laos, Vientiane, Lao Democratic People's Republic
| | - Claude P Muller
- Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg.,Lao-Lux-Laboratory, Institute Pasteur Du Laos, Vientiane, Lao Democratic People's Republic.,Laboratoire National de Santé, Dudelange, Luxembourg
| | - Somphou Sayasone
- Lao Tropical and Public Health Institute, Vientiane, Lao Democratic People's Republic
| | - Antony P Black
- Lao-Lux-Laboratory, Institute Pasteur Du Laos, Vientiane, Lao Democratic People's Republic
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17
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Ounnavong P, Chanthavilay P, Khampanisong P, Reinharz D, Muller CP, Black AP. Seroprevalence of anti-tetanus antibodies in mothers and cord blood and associated factors in health-care settings in Lao People's Democratic Republic. Vaccine 2019; 38:1234-1240. [PMID: 31735506 DOI: 10.1016/j.vaccine.2019.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND Maternal neonatal tetanus (MNT) was eliminated from Lao People's Democratic Republic (PDR) in 2014. WHO recommends 80% coverage of 2 or more tetanus vaccinations (TT2+) in pregnancy to maintain MNT control. Vaccination coverage in Lao PDR varies among regions although the reasons are not clear. METHODS 185 pregnant women giving birth in three district hospitals in Savannakhet province, Lao PDR were recruited. A questionnaire was administered to determine factors associated with seroprotection and blood was taken from mother and cord blood to be tested for anti-tetanus antibodies by ELISA. RESULTS 77% of mothers and 79% of newborns had sufficiently protective antibody titres (>0.5 IU/ml) against tetanus. Only 70% of the mothers received one dose of TT vaccination during antenatal care (ANC) consultation and 45% received the recommended two injections. Although most of the vaccination took place during ANC 1 and 2, many were missed at these time-points. Anti-tetanus seroprotection in the mothers was associated with maternal age, number of ANC visits, number of TT vaccinations during and before pregnancy and gestational age. CONCLUSION Seroprevalence of anti-tetanus antibodies in mothers and newborns was intermediate but TT2+ coverage was low in healthcare settings in Lao PDR. TT2+ coverage during ANC is likely to be significantly lower in settings with less robust ANC practices. Missed opportunities to vaccinate in ANC 1 and 2 suggest a need to promote vaccine awareness and vaccination at first ANC visit. A booster dose of TT containing vaccine should be considered for children aged between 4 and 7 years old.
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Affiliation(s)
- Phoumsavath Ounnavong
- Institut de la Francophonie pour la Medecine Tropicale, Lao Democratic People's Republic
| | | | | | - Daniel Reinharz
- Institut de la Francophonie pour la Medecine Tropicale, Lao Democratic People's Republic; Department of Social and Preventive Medicine, Laval University, Canada(2)
| | - Claude P Muller
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao Democratic People's Republic; Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg; Laboratoire Nationale de Santé, Dudelange, Luxembourg
| | - Antony P Black
- Lao-Lux Laboratory, Institut Pasteur du Laos, Vientiane, Lao Democratic People's Republic.
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18
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Norizuki M, Kitamura T, Komada K, Sugiyama M, Mizokami M, Xeuatvongsa A, Som-Oulay V, Vongphrachanh P, Machida M, Wada K, Ishii K, Kiyohara T, Wakita T, Hachiya M. Serologic testing of randomly selected children after hepatitis B vaccination: a cross-sectional population-based study in Lao People's Democratic Republic. BMC Infect Dis 2019; 19:507. [PMID: 31182043 PMCID: PMC6558699 DOI: 10.1186/s12879-019-4086-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 05/14/2019] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Population immunity against hepatitis B virus (HBV) in Lao People's Demographic Republic (PDR) has not been examined since the national HBV vaccination program was started in 2002. Vaccine has been observed to be frozen at times during cold-chain transport in vaccination programs in Lao PDR and other developing countries, which will inactivate the vaccine. Therefore, this study used post-vaccination serologic testing to evaluate the effects of HBV immunization in Lao PDR. METHODS A cross-sectional serologic study was conducted among children (age range, 5-9 years) and mothers (15-45 years) who were randomly selected using probability-proportional-to-size sampling from central Lao PDR. Blood samples were collected as dried blood spots (DBS) and analyzed using chemiluminescent microparticle immunoassay to detect anti-hepatitis B surface (HBs) titers. We also evaluated the correlation between anti-HBs levels measured in DBS and serum among healthy healthcare workers in Vientiane. RESULTS Anti-HBs titers from DBS were strongly correlated with serum levels (correlation coefficient = 0.999) in all 12 healthcare workers evaluated. A linear regression model showed that 10 mIU/mL of serum anti-HBs was equivalent to 3.45 mIU/mL (95% CI: 3.06-3.85) of DBS. Among 911 mother-child pairs tested, 171 children had documentation of vaccination. Of the 147 children who had received ≥3 doses of the hepatitis B vaccine, 1 (0.7%) was positive for anti-HBs. The remaining 24 children received the hepatitis B vaccine only twice, once or no dose. CONCLUSIONS The results showed extremely low positivity for anti-HBs among vaccinated children in central Lao PDR. Therefore, post-vaccination serologic testing is important to evaluate population immunity against HBV infection. DBS testing is a potential low-cost tool to evaluating the effectiveness of HBV vaccination programs.
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Affiliation(s)
- Masataro Norizuki
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
- Graduate School of Medicine, International University of Health and Welfare Graduate School, Minato, Tokyo, Japan
| | - Tomomi Kitamura
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Kenichi Komada
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Masaya Sugiyama
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
| | - Masashi Mizokami
- The Research Center for Hepatitis and Immunology, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
| | - Anonh Xeuatvongsa
- National Immunization Program, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR
| | - Vilasak Som-Oulay
- National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR
| | - Phengta Vongphrachanh
- National Center for Laboratory and Epidemiology, Ministry of Health, Lao PDR, Simeuang Road, Vientiane, Lao PDR
| | - Munehito Machida
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
- Department of Global Health, Faculty of Medicine, Institute of Medical, Pharmaceutical and health Sciences, Kanazawa University, Kanazawa, Ishikawa Japan
| | - Koji Wada
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
- Graduate School of Medicine, International University of Health and Welfare Graduate School, Minato, Tokyo, Japan
| | - Koji Ishii
- Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
| | - Tomoko Kiyohara
- Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Musashi-murayama, Tokyo, Japan
| | - Masahiko Hachiya
- Bureau of International Health Cooperation, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
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19
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Immunity levels to poliovirus in Lao children and adults before the vaccine-derived poliovirus outbreak: A retrospective study. PLoS One 2018; 13:e0197370. [PMID: 29763458 PMCID: PMC5953481 DOI: 10.1371/journal.pone.0197370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 05/01/2018] [Indexed: 11/24/2022] Open
Abstract
In 2015, several provinces in Lao People's Democratic Republic (Lao PDR) experienced a vaccine-derived poliovirus outbreak. This survey was conducted (i) to evaluate the vaccination coverage in different settings and cohorts using the seroprevalence of anti-poliovirus (PV) antibodies as a surrogate measure, and (ii) to explore the usefulness of an ELISA in a country with limited resources and a specific epidemiological setting. IgG antibodies were assessed by ELISA in Lao children (n = 1216) and adults (n = 1228), including blood donors and health care workers. Protective antibody titers against the 3 vaccine serotypes were determined by microneutralization (VNT) in a subset of participants. More than 92% of the children had anti-poliovirus antibodies, regardless of nutritional status or access to health care, highlighting the success of the vaccination outreach activities in the country. In contrast, anti-poliovirus seroprevalence reached only 81.7% in blood donors and 71.9% in health care workers. Participants born before the introduction of poliovirus vaccination in Lao PDR were considerably less likely to be seropositive. These findings align with the epidemiology of the outbreak. Neutralizing antibodies against at least one of the 3 poliovirus serotypes were detected in all children (99/99) and 93/99 had antibodies against all serotypes. Similarly, all health care workers had neutralizing antibodies against at least one and 92/99 against all serotypes. The comparison of both assays shows an acceptable underestimation of vaccine coverage in children by ELISA, but a low sensitivity of the ELISA in the adults. We show that the ELISA is a reasonable alternative to the VNT in particular in vaccinated children, that an improved version should be serotype specific, and that negativity thresholds should be revisited for optimal sensitivity and specificity. Thus, polio-free countries with an uncertain vaccination coverage and limited laboratory capacity, that are at risk of vaccine-derived poliovirus outbreaks or of re-importation of wild poliovirus may benefit from an improved ELISA for cohort studies to evaluate their immunization program in children.
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