“Previous immunization studies in HIV infected children and adolescents have demonstrated that their responses to vaccination are not as good as in immune competent subjects of the same age,” Dr. Jorge Lujan-Zilbermann from University of South Florida College of Medicine, Tampa, Florida told Reuters Health in an email. “The study confirmed our hypothesis that two doses of MCV4 are necessary to obtain an adequate immune response.”
Dr. Lujan-Zilbermann and colleagues in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group P1065 Protocol Team describe the long-term immunogenicity (at 28 and 72 weeks post-entry) and safety of 1 dose versus 2 doses of MCV4 in 286 youth infected with HIV.
Youth with CD4% of at least 15% were more than 3 times more likely to respond to a second dose of MCV4 than to the first dose at week 28 and 52% more likely to respond at week 72.
Response rates in this group were higher for those with higher screening CD4% and Black race and lower for those with entry HIV viral loads above 10,000 copies/mL and those older than 15 years at entry.
Among youth with CD4% below 15%, there were no significant changes in response rates after the second dose of MCV4.
Response rates differed among the 4 serogroups, with antibody titers and response rates lowest for serogroup C throughout the study.
There were no adverse events in the 42 days after receiving the second MCV4 dose among youth with CD4 of at least 15%, but 6.5% of youth with lower CD4 percentages reported grade 3 or higher signs/symptoms.
None of the subjects developed Guillain-Barré syndrome, invasive meningococcal infection, or meningitis during the study period.
“HIV infected youth need two doses of MCV4 in their primary series to obtain an adequate immune response to the vaccine,” Dr. Lujan-Zilbermann concluded. “We are currently conducting a study evaluating the response to a booster dose of MCV4, three years after the first series of two doses.”
“It is very important to continue to do clinical trials in HIV infected subjects to assess their responses to vaccinations since they are different than the population in which the vaccine has been tested initially,” Dr. Lujan-Zilbermann added.