Safety and Immunogenicity of a Live, Attenuated Rotavirus Vaccine (RotaTeq™) in HIV-1 Infected and Uninfected Children Born to HIV-1-Infected Mothers

International Maternal Pediatric Adolescent AIDS Clinical Trials Network (IMPAACT) P1072 was an international Phase II randomized double-blind study to assess the safety and immunogenicity of a live, attenuated rotavirus vaccine (RotaTeq) in HIV-1 infected (n=160) and uninfected (n=160) children born to HIV-1 infected mothers. Infants between 2 and <15 weeks of age at screening were assigned to one of four strata, based on HIV-1 status and in the HIV-1 infected, by Cluster of Differentiation percentage (CD4%) [≥ 20% (n=80), 15% ≤ CD4% < 20% (n=60) and < 15% (n=20)]. Screening had to be completed such that the first dose of study vaccine was administered when the participant was 4 to < 15 weeks of age. Within each stratum infants were randomized to receive either active RotaTeq vaccine (three doses of 2.0 mL each at intervals of 4 to 10 weeks with the third dose administered by 32 weeks of age) or placebo on the same schedule.

Participants were followed until six weeks after the last dose of vaccine, with visits at 7, 14, 21 and 42 days after each dose. The day 42 visit after the first two study doses was only required if the next study vaccination was done more than 42 days after the previous dose. At each visit, data were recorded on adverse events observed by the caretaker and investigator, including signs/symptoms ≥ grade 1 and new clinically significant diagnoses. No hematology or chemistry testing was required by the protocol, but sites could record laboratory results in the database if the results were pertinent. Stool samples for fecal shedding were collected at entry, days 7, 14, 21 and 42 after the first vaccination, 7 and 21 days after the second and third vaccinations, and at any unplanned visits for gastroenteritis. Serum for immunogenicity testing was collected at entry and 14 days (or 42 days if not collected at 14 days) after the third vaccination.

In January 2012, rotavirus vaccine (Rotarix) became available as standard of care at the Lusaka study site in Zambia, so enrollment ceased at that site. Infants already enrolled and within the age range where they could receive the Rotarix series were unblinded. Those on placebo were given Rotarix. Those in the active vaccine arm continued receiving the study vaccine. All infants continued to attend study visits. A similar procedure was followed after July 2012, when Rotarix became available as standard of care in Botswana.

During 2013, Zimbabwe was the only site enrolling participants, most of whom were HIV-1 uninfected. The team decided to close the study to enrollment prematurely at the end of September 2013 with a total of 126 HIV-1 uninfected (79% of the target of 160) and 76 HIV-1 infected (48% of the target: 81% of those with CD4% ≥ 20% and 14% of those with CD4% < 20%). Because of the low enrollment of HIV-1 infected infants with lower CD4%, results in the HIV-1 infected stratum were reported combined across CD4% strata.

Baseline characteristics are presented 'as-randomized'. Safety data are presented 'as-randomized' and include all follow-up on study up to 42 days after the third vaccination. Immunogenicity results are presented for the 'per-protocol' population which includes participants who received the 'as-randomized' vaccine and completed the three vaccinations within the required windows (first vaccination between 4 and < 15 weeks of age, subsequent vaccinations at least 28 days after previous vaccination, and third dose by 32 weeks of age).