A cluster RCT to determine the effect on overall mortality of providing MV to children after 1 year of age
Mortality in 1-4-year-old children will be 30% lower in villages randomized to receive MV compared to villages that do not receive MV for children above 1 year.
Previous observational studies suggest that MV has beneficial NSEs also among older children. However, donors assess national programs by vaccine coverage by 1 year of age. Thus, the Expanded Program on Immunization (EPI) in Guinea-Bissau focuses on children below 1 year of age and older children are no longer entitled to MV. This situation makes it urgent to test the NSEs of MV to older children.
The study will take place in 182 villages in all 9 health regions in rural Guinea-Bissau. Mobile BHP teams visit these villages every 6 months. In each region, the villages will be randomized to MV for all children aged 1-3 years or to follow current EPI policy. Follow-up will take place at the mobile teams’ visits.
Outcomes and sample size
The main outcome is mortality. Around 1,000 children are eligible for enrolment per year. With an expected 8.3% mortality and 8% loss to follow-up, adjusting for design effect, 3676 children are needed to detect a 30% reduction in mortality.
An estimate of the effect on overall mortality of providing MV versus not providing MV to 1-3-year-old children.
Due to the general MV campaigns every 3-4 years, outbreaks of measles are unlikely. If the study finds the expected beneficial effects on overall mortality in a situation with no or limited measles, it will contribute to the paradigm shift. At the policy level the results would be used to persuade Guinean authorities and donors to vaccinate all children, and to persuade the donors to focus on other markers of success than vaccination coverage by 1 year of age.
The protocol has been approved by the GEC and the DNCBRE. No child will be deprived of vaccines which it would otherwise have received and the trial will result in increased MV coverage. In the unlikely event of a measles epidemic, the EPI will organize MV campaigns and the study would be temporarily halted.
A total of 2 PhD students will be involved in WP1 and WP2, ideally with 6 months’ overlap. This will secure that the two trials are constantly supervised over a period of 5½ years. The specific PhD projects will be defined within the frames of the trials. The PhD students will be supervised by members of the CVIVA group. The PhD students' academic focus will continuously be evaluated by CVIVA's steering committee. Research results will be published in leading international journals and in conference proceedings, and in all cases, the Center and the Danish National Research Foundation be thanked for support. The aim is that the PhD students will spend longer periods at the Center, for example in connection with the statistical analysis of data. The PhD students will also participate in all key meetings and activities of the Center and contribute to the Center's general activities.