Can HIV Reverse Childhood Vaccinations?

Can HIV Reverse Childhood Vaccinations?

New research reveals a disturbing problem for people living with HIV. According to a recent study published in the Journal of Infectious Diseases, HIV-positive people can lose their immunity to the smallpox virus — even if they were vaccinated as children and currently have their HIV suppressed due to antiretroviral therapy (ART).

As reported by EurekAlert! (a service of AAAS, the American Association for the Advancement of Science), researchers are calling this newfound issue “HIV-associated immune amnesia.”

This finding could help explain why people living with HIV still tend to have shorter lives on average than those who are HIV-negative, even despite being undetectable. The study reinforces similar recent findings published in the journals Science and Science Immunology which found that the immune systems of children who had contracted measles seemed to later “forget” its immunity against other illnesses, like influenza.

The study was led by Mark K. Slifka, Ph.D., a professor of molecular microbiology and immunology at the Oregon Health & Science University School of Medicine and Oregon National Primate Research Center.

The T-cell and antibody responses of 100 women with both positive and negative HIV statuses, and who were vaccinated against smallpox in their childhood, were compared by Slifka and his team.

The team found that the immune systems of the HIV-positive women who were on ART had a limited response when their blood was exposed to the vaccina virus, a component used in the smallpox vaccine.

Usually people vaccinated against smallpox have CD4 T cells that “remember” the virus, which then respond in large numbers if and when ever exposed to it again. Smallpox-specific CD4 T cells are typically maintained for up to 75 years after vaccination.

Despite the fact that ART works by boosting CD4 T cell counts in people living with HIV, Slifka and his team conclude that, ultimately, these findings indicate that while ART may boost total T cell counts overall, it’s not able to successfully recover the virus-specific T cells generated from prior childhood vaccinations.

The researchers’ next plan to evaluate whether or not the same issue occurs in HIV-positive men, and if people living with HIV also lose immune memory to other diseases.

By Desirée Guerrero