Children who suffer from HIV infection and undergo highly active antiretroviral therapy (HAART) may have to get themselves revaccinated in order to maintain immunity against preventable childhood diseases, a new study has found.

Researchers at the John Hopkins Bloomberg School of Public Health came up with this report after analyzing the results of 38 published studies. The latest study has been included in the September issue of the medical magazine The Lancet Infectious Diseases.

The research team at the John Hopkins conducted the review of the earlier studies and found that children treated with HAART, a combination of three or more potent drugs that target HIV, were susceptible to diseases that are otherwise preventable via vaccines.

The progressive effects of the HIV infection on the immune system in providing a response to diseases is so strong that several infected children have poor responses to vaccines, says study author Dr. William Moss, an associate professor in the epidemiology department.

The hospital has issued a press release in which Dr. Moss says that fewer children infected with HIV achieve protective immunity, and those who do might experience greater and more rapid waning of immunity. These results suggest that children on HAART would benefit from revaccination, but levels of protective immunity might need to be monitored and some children may need additional vaccine doses to maintain protective immunity.

Currently, there are no standard or official recommendations on revaccination of HIV-infected children on highly active antiretroviral therapy. "Vaccination policies and strategies for children infected with HIV on HAART should be developed in regions of high HIV prevalence to ensure adequate individual and population immunity," says lead author Catherine Sutcliffe.

"Without such recommendations, as treatment programs scale up and more children receive HAART and live into adolescence and adulthood, a larger proportion of these children could be susceptible to childhood diseases," she says in the press release.