Current Research and Scholarly Interests
The research I have conducted has been focused on epidemiologic aspects of viral vaccine development and prevention of perinatal HIV transmission. A major project has been to identify the molecular epidemiology of factors affecting the immunogenicity of oral polio vaccine (OPV) among children living in developing areas of the world, where OPV immunogenicity is poor. We have identified several factors which affect the poor immunogenicity of OPV and will conduct clinical studies to attempt to improve immunogenicity. We are now working on ways to understand the transmission and circulation of polio vaccine derived viruses, which may cause polio, and how to use this information in global eradication of polio. I also work on perinatal HIV infection, including strategies to prevent breastfeeding transmission in developing settings as well as understanding how to maximize prevention strategies among pregnant women in developed countries.
The Maldonado Group recently received a grant from the Bill & Melinda Gates Foundation for a 2.5 year study investigating the dynamics of oral poliovirus vaccine (OPV) household and community transmission in 3 communities in Orizaba, Veracruz, Mexico. Mexico provides a unique environment to study OPV transmission. Currently, Mexican children receive inactivated poliovirus vaccine (IPV) in their primary vaccination series. In addition, children ≤5 years old who have received at least 2 doses of IPV are eligible to receive OPV during biannual National Immunization Weeks. Our study will specifically assess the impact of different OPV vaccination rates during the February 2015 National Immunization Week on intra- and inter-household transmission of OPV. The outcome of this project will inform public policy decision-making regarding OPV cessation and the polio end-game.
A second ongoing project has been to define the ontogeny of the immune response to measles vaccine among young infants. The purpose is to identify specific humoral and cell-mediated immune responses to measles vaccine which affect vaccine immunogenicity and induce the immunosuppressive effects associated with measles vaccination.
A final project I have conducted since 1989 involves a long term natural history study of infants with perinatal HIV exposure and infection. This computer-based study involves following all HIV-exposed and infected infants living in the Northern California and defining factors associated with progression of HIV-related disease.