On June 11, 2009, the World Health Organization declared a pandemic of the new H1N1 influenza virus, after the virus had caused significant fevers and respiratory illnesses in Mexico and the United States. Pregnant women are at an increased risk of complications from influenza. HIV infected people tend to have lower than normal antibody responses to seasonal influenza vaccines. Data suggest that larger than average doses of a vaccine counteract a weak antibody response. Preliminary results from ongoing studies of influenza A (H1N1) 2009 monovalent vaccines indicate that the vaccine may increase immune activation. This study tested the safety and antibody response of high doses of the influenza A (H1N1) 2009 monovalent vaccine in pregnant women infected with HIV.~Participation in this study lasted until 6 months after participants had delivered their babies or up to 52 weeks. Participants received two doses of the H1N1 vaccine at study entry and after 21 days. Each dose consisted of two intramuscular injections (four total injections). On the days of the injections, participants had their babies' heart rates checked before and after vaccination. At these visits, and at follow-up visits on Days 21, 31, and 42, participants completed a review of symptoms, physical and neurological exams, and a blood draw. For 10 days after receiving each dose of the vaccine, participants were asked to keep track of their temperatures and symptoms or reactions in a journal. Participants were contacted on Day 2 and Day 10 after the first dose of vaccine was given and on Day 2 after the second dose of vaccine was given. Some participants also received a phone call after 6 months.~At delivery of each participant's baby, blood was drawn from both the mother and umbilical cord (or from the baby if the cord blood could not be obtained). At 3 and 6 months after delivery, participants came in for follow-up visits involving, for both mother and child, a review of symptoms, brief physical exams, and blood draws (at 6 months only some women had a clinic visit, the rest received a phone call).
Both pregnant women and people infected with HIV are at increased risk of viral infection, including influenza infection. Pregnant women infected with HIV may be at particular risk of infection from the new H1N1 influenza virus. This study tested the safety and immunogenicity of an H1N1 influenza vaccine in pregnant women infected with HIV.