Revaccination of HIV infected children

Immunologic Basis for Revaccination of HIV-infected Children Receiving HAART
This article is an interesting discussion of potential public health surrounding HIV positive children and immunizations. Untreated HIV reduces the ability of a child’s immune system to respond to infections and vaccines. As the mortality rate decreases, there is a growing need to understand how HAART affects immunity to vaccine preventable infections, with the goal to improve individual and public health. Studies have demonstrated that immune reconstitution following HAART mirrors that of the immune system over the individual life span. Young children with few memory cells will reconstitute with naïve T cells. Adolescents or young adults will reconstitute with a combination of naïve T cells and memory T cell expansion. Older adults will reconstitute with the expansion of memory T cells. When a child is infected perinatally it is believed this predisposes the immune system towards effector T cells.
The authors use the measles virus as a model to study immunological memory. Exposure to measles generally results in lifelong protective IgG antibody levels. When a child is HIV infected there are typically low levels of immunity seen in response to vaccines given prior to initiation of HAART. Studies with Zambian and Thai children have shown a decrease in immunity levels over time, producing a group of measles susceptible children. Determination of the optimal time to revaccinate HIV positive children is not yet clear but emerging data suggests that children who respond to HAART may successfully be revaccinated when CD4 cells return to normal levels for age.
Rainwater-Lovett, K. & Moss, W. J. (2011). Immunologic basis for revaccination of HIV-infected Children receiving HAART. Future Virology, 6(1), 59-71.