Investigator(s)
| WHO Technical Officer |
Sigrun Roesel Technical Officer IVD/CDS WHO SEARO Sigrun Roesel 
|
| Principal Investigator |
Nashiya Abdhul Gafoor Director, National Vaccine Program, Health Protection Agency, Ministry of Health, Maldives Nashiya Abdhul Gafoor
|
Title(s) and abstract
| Scientific title | Assessment of Hepatitis B Surface Antigen Prevalence among Children in Maldives to evaluate the Impact of the Hepatitis B Vaccination Program |
| Public title | Hepatitis B sero survey in Maldives |
| Background | Hepatitis B vaccine (HepB), including the birth dose (BD), was introduced nationwide in Maldives in 1993, and high immunization coverage has been sustained. The HepB BD coverage is ≥97% since 2001 and coverage of 3 doses of hepatitis B vaccine is over 96% since 2000. High immunization coverage has been achieved in all atolls. In 2021, all atolls have over 99% HepB BD coverage. The HepB BD is given to all infants regardless of their mothers’ hepatitis B status. Antenatal screening of chronic hepatitis B is routinely conducted in all hospitals and health centers in Maldives. However, the data are not systematically collected or analyzed at the national level. There is a lack of data on the prevalence of chronic hepatitis B among the general population. In 2016, the South-East Asia Regional Immunization Technical Advisory Group recommended setting the target of reducing the prevalence of chronic hepatitis B among 5-year-old children to less than 1% by 2020. Countries are verified to having achieved this target through nationally representative serosurveys, and evidence of high hepatitis B immunization coverage. |
| Objectives | 1) To measure the prevalence of hepatitis B surface antigen (HBsAg) among Grade 1 school children (the majority of whom are about 6-7 years of age). 2) To collect immunization data and timeliness of vaccination and calculate effectiveness that hepatitis B vaccine has on preventing chronic infection. |
| Study Methods | A national cross-sectional school-based cluster survey will be conducted to estimate the prevalence of HBsAg among school children in Grade 1 in Maldives. Basic demographic information and immunization history will be collected for all Grade 1 school children in the selected classes. Children whose parents/legal guardians provided informed consent will be tested for HBsAg. A pre-testing of the survey protocol will be conducted in a school not selected into the sample prior to the national implementation of the survey. The same procedures described in the following sections will be performed during the pre-testing. The purpose of the exercise is to test and validate the questionnaires and also do a test run of the rapid diagnostic kits to be used. Since the pre- testing will be done using focal points and laboratory focal points that will be conducting the survey, it would give them the opportunity to understand and familiarize themselves with the survey implementation. The exercise will also be accompanied by an intensive training on all the components of survey implementation. Definitions of terms ● Chronic hepatitis B virus (HBV) infection: participants with a positive HBsAg test ● Not currently infected with HBV: participants with a negative HBsAg test Limitations: This study does not measure the antibodies to HBsAg, and therefore does not assess the immunogenicity of the hepatitis B vaccine. This study does not test or ask the mothers for their HBV infection status. Thus, it does not measure the rate of perinatal infection, or the effectiveness of the vaccine in preventing perinatal infection. While the data generated may be ultimately cross tabulated to calculate vaccine efficacy, the survey will not have been statistically powered with that intention. |
| Expected outcomes and use of results | The study will generate the estimate of the prevalence of chronic hepatitis B among children in Maldives from a nationally representative sample. The result will be the primary evidence to assess if the hepatitis B control target has been achieved in the Maldives. A meeting with stakeholders will be held to disseminate the result of the survey. A report or a manuscript detailing the survey method and results will be published. The testing result will not be released to the public at school/island levels to protect anonymity of the participants. At the request of the Ministry of Health, Maldives, to WHO, a verification committee consisting of independent international experts will be convened to review the survey results and make recommendations to WHO whether the hepatitis B control target is achieved. |
| Keywords | Hepatitis B control, sero survey, immunization |
Research Details
| Student research | No |
| Start Date | 01-Feb-2023 |
| End Date | 30-Jun-2023 |
| Key Implementing Institution | Health Protection Agency Maldives |
| Multi-country research | No |
| Nationwide research | Yes |
| Research Domain(s) | Communicable Disease Research |
| Research field(s) | Immunization/Vaccine Preventable Disease |
| Involves human subjects | Yes |
| Population-Based Survey | |
| Data Collection | Primary data |
| Proposal reviewed by other Committee | Final decision available |