Tetanus immunity after diphtheria, tetanus toxoids, and acellular pertussis vaccination in children with clinically stable HIV infection

Background HIV infection often impairs the immune response to childhood vaccines. Objective We sought to study the ability of HIV-infected children receiving highly active antiretroviral therapy (HAART) to generate a booster response to immunization with a recall antigen to which they had lost humoral immunity. Methods Diphtheria, tetanus toxoids, and acellular pertussis (DTaP) vaccination was given at either 16 or 36 weeks after initiation of HAART to 37 HIV-infected children 2 to 9 years of age with a history of DTaP or diphtheria-tetanus-pertussis receipt who had negative tetanus antibody titers (≤1:243) at baseline. Results There was a clear increase in tetanus titers after vaccination, with an increase of 27-fold over the baseline values at weeks 4 and 8. The effect on tetanus titers faded to a 9-fold and 3-fold increase over baseline values at weeks 18 and 32, respectively. DTaP vaccination did not affect HIV-1 RNA viral load or CD4 percentage or cell count. There was no increase in either acute or long-term adverse events associated with the DTaP vaccination. Conclusion Although children with stable HIV infection receiving HAART can mount antigen-specific responses to tetanus immunization, the durability of these responses might be limited. Long-term monitoring of specific immune function in such children is indicated.