NEW YORK (Reuters Health) – A second dose of quadrivalent meningococcal conjugate vaccine (MCV4) six months after the first dose significantly improves response rates in youths infected with HIV, researchers say.
“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. The study confirmed our hypothesis that two doses of MCV4 are necessary to obtain an adequate immune response,” Dr. Jorge Lujan-Zilbermann from University of South Florida College of Medicine, Tampa, Florida told Reuters Health in an email.
In the May 24th online issue of The Journal of Pediatrics, Dr. Lujan-Zilbermann and colleagues compared the long-term immunogenicity (at 28 and 72 weeks post-entry) and safety of one dose versus two doses of MCV4 in 286 HIV-infected young people with an average age of roughly 18 years.
Rather than stratifying patients based on CD4 T-lymphocyte count, the authors used CD4 percentage. A week-28 response was defined as a four-fold increase over baseline.
Among youths with CD4% below 15, a second dose of MCV4 had no effect on response rates.
But youths with a CD4% of at least 15 were more than three times more likely to respond to a second dose of MCV4 than to the first dose by week 28 and 52% more likely to respond by 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.
Response rates differed for the four meningococcal 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 for subjects with CD4% of at least 15, but 6.5% of youth with lower CD4 percentages had 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,” he added.
J Pediatr 2012.