HIV-Infected Children Living in Central Africa Have Low Persistence of Antibodies to Vaccines Used in the Expanded Program on Immunization

Mathurin C Tejiokem,Ida Penda,Gilbert Tene,Jean C Gody,Régis Pouillot,Elisabeth Njamkepo,Dominique Rousset,Anfumbom Kfutwah,Ionela Gouandjika,Catherine Bilong,Lydie Béniguel,Frédéric Tangy,Laurence Baril,Marie-Claire Endegue Zanga

doi:10.1371/journal.pone.0001260

Abstract

BackgroundThe Expanded Program on Immunization (EPI) is the most cost-effective measures to control vaccine-preventable diseases. Currently, the EPI schedule is similar for HIV-infected children; the introduction of antiretroviral therapy (ART) should considerably prolong their life expectancy.Methods and Principal FindingsTo evaluate the persistence of antibodies to the EPI vaccines in HIV-infected and HIV-exposed uninfected children who previously received these vaccines in routine clinical practice, we conducted a cross-sectional study of children, aged 18 to 36 months, born to HIV-infected mothers and living in Central Africa. We tested blood samples for antibodies to the combined diphtheria, tetanus, and whole-cell pertussis (DTwP), the measles and the oral polio (OPV) vaccines. We enrolled 51 HIV-infected children of whom 33 were receiving ART, and 78 HIV-uninfected children born to HIV-infected women. A lower proportion of HIV-infected children than uninfected children had antibodies to the tested antigens with the exception of the OPV types 1 and 2. This difference was substantial for the measles vaccine (20% of the HIV-infected children and 56% of the HIV-exposed uninfected children, p<0.0001). We observed a high risk of low antibody levels for all EPI vaccines, except OPV types 1 and 2, in HIV-infected children with severe immunodeficiency (CD4+ T cells <25%).Conclusions and SignificanceChildren were examined at a time when their antibody concentrations to EPI vaccines would have still not undergone significant decay. However, we showed that the antibody concentrations were lowered in HIV-infected children. Moreover, antibody concentration after a single dose of the measles vaccine was substantially lower than expected, particularly low in HIV-infected children with low CD4+ T cell counts. This study supports the need for a second dose of the measles vaccine and for a booster dose of the DTwP and OPV vaccines to maintain the antibody concentrations in HIV-infected and HIV-exposed uninfected children.

Highlights

Pediatric HIV infection is a major public health threat
We evaluated the persistence of antibody levels in HIV-infected and HIV-exposed uninfected children born to HIVinfected mothers, living in Central Africa and who previously received Expanded Program on Immunization (EPI) vaccines in routine clinical practice
Composite categorical variables were created to evaluate the effect of HIV infection: i) HIV status combined with the percentage of CD4+ T cells (HIV-exposed uninfected, HIV infected and $25% CD4+ T cells, HIV infected and,25% CD4+ T cells) [10]; ii) HIV status combined with HIV viral load (VL) (HIVexposed uninfected, HIV infected and VL,10,000 copies/ml, HIV infected and VL $10,000 copies/ml) [11]; and iii) HIV status combined with duration of antiretroviral therapy (ART) (HIV-exposed uninfected, HIV infected and $6 months ART, HIV infected and,6 months of ART or no ART)

Summary

Introduction

Pediatric HIV infection is a major public health threat. Two thirds of the 700,000 [630,000 to 820,000] children less than 15 years old newly infected with HIV in 2005 were living in sub-Saharan Africa [1]. Mother to child transmission of HIV is still a major route of infection for children This is related mainly to insufficient access to prevention methods, HIV screening and antiretroviral treatment (ART) in developing countries. A lower proportion of HIV-infected children than uninfected children had antibodies to the tested antigens with the exception of the OPV types 1 and 2. This difference was substantial for the measles vaccine (20% of the HIV-infected children and 56% of the HIV-exposed uninfected children, p,0.0001). This study supports the need for a second dose of the measles vaccine and for a booster dose of the DTwP and OPV vaccines to maintain the antibody concentrations in HIV-infected and HIV-exposed uninfected children

Methods

Results

Conclusion