Population differences in vaccine response (POPVAC)-2: the impact of environmental exposures and selected interventions on waning of vaccine-induced immune responses

"Vaccines are a key weapon against infectious diseases which continue to have major detrimental impacts on health and development in in low-income countries (LICs). However, the effectiveness of some vaccines is reduced in tropical LICs and in rural vs urban settings. For example, the TB vaccine, BCG, provides 80% protection in some temperate countries, but 0% in some tropical settings.

A potential explanation for this phenomena includes exposure to parasites so to further understanding we will compare the vaccine responses for Ugandan adolescents among three groups: (1) urban-dwellers participating in our Entebbe Mother and Baby Study birth cohort who have low parasite exposure; (2) island communities where over 80% have schistosomiasis (a parasitic worm infection); (3) rural communities with high malaria exposure, where over 50% of school-children unknowingly have malaria. We will also look at how parasitic infections interact with other viral or bacterial infections (“transkingdom” effects) and how these indirect effects impact the immune system.

Finally, we will use statistical approaches to explore how the urban-rural environment, parasites, ""transkingdom"" effects and immune responses interrelate to determine vaccine responses. This fundamental information will contribute to the development of suitable vaccines for populations living in tropical LIC settings and inform public health policy to improve effectiveness of vaccine programmes."