CD4 and HIV infectious disease: Evidence from studies in children demonstrates that HIV infection lowers antibody response following vaccination, and high CD4+ counts at vaccination improve antibody response.41 With the lack of data on the burden of disease in HIV-infected adolescents and adults, the recommendation would be that only pregnant women, regardless of CD4+ counts or viral load, be vaccinated (with acellular vaccine) during each pregnancy until there is more evidence to do otherwise.