Infants who become infected with HIV from their mothers can have a normal immune response to childhood vaccines, provided they begin treatment with highly active antiretroviral therapy in the first year of life, the results of a small study suggest.

Highly active antiretroviral therapy, better known as HAART, involves treatment with three or more drugs, of various classes, to combat HIV.

When HAART begins is the key factor that will determine whether an HIV-infected child will develop a normal vaccine response and how long it will last, Dr. Paolo Rossi, at the University of Tor Vergata in Rome, and colleagues state in the Proceedings of the National Academy of Sciences.

With HIV infection, they note, there is a drop in the antibody-producing cells induced by a vaccine for a particular disease. As a result, the child’s immunity to the disease is reduced. Whether the timing of HAART could help preserve these cells and promote a normal immune response was unclear.

To investigate, Rossi’s team studied 70 children infected at birth with HIV and 50 healthy comparison subjects.

Thirteen infected subjects received HAART before 12 months of age, 6 received no treatment, and the remaining children were treated later in life. All of the children received recommended vaccinations for measles and tetanus.

Patients receiving HAART within the first 12 months of life maintained normal levels of antibody-producing cells, whereas low levels were seen in the other groups.

The findings support early treatment with HAART as a means of preserving a normal immune response in infants with HIV, the authors conclude. For children who start treatment beyond the first year of life, the usual vaccine schedules may need to be revised, they add.

SOURCE: Proceedings of the National Academy of Sciences, April 27th early online edition, 2009.