October 25, 2008
A poster presentation at the joint 2008 ICAAC / IDSA in Washington, DC showed positive results from a study of the meningococcal vaccine (MCV4, also called Menactra) in youth living with HIV. The MCV4 vaccine prevents infection with the N. meningitidis bacteria that causes several meningococcal diseases such as meningitis. The safety of the vaccine has not been studied in HIV-positive adolescents. (Another vaccine, called Menomune, is also available, although it likely provides fewer years of protection than Menactra.)
Meningococcal infections are easily passed through saliva because the bacteria are found in the nasal cavity and upper throat of about 1 in every 2 people. This can occur through coughing, kissing and chewing on toys. Symptoms can be flu-like and include fatigue, but they can quickly progress from headache, stiff neck and fever to coma and death.
This phase I/II study from 27 IMPAACT (International Maternal Pediatric Adolescent AIDS Clinical Trials) sites followed 319 youth aged 11 to 24 years. Three groups were studied: group 1 (39 youth) with a CD4% of <15%, group 2 (127) with a CD4% of 15-24%, and group 3 (153) with a CD4% of >=25%. (A CD4% is the percent of all lymphocytes that are CD4 cells from a blood sample. A healthy person usually has about a 40% CD4 percentage.)
All three groups took one dose of the MCV4 vaccine at the start of the study. At 24 weeks, all of group 1 received a second dose while those in groups 2 and 3 were randomized to take or not take a second dose.
Adverse events were generally mild. These included injection site reactions such as pain and tingling and other adverse events such as headache, abdominal pain and neutropenia. Those youth with HIV levels above 1,000 were twice as likely to experience an adverse event. As well, no cases of Guillain-Barré Syndrome occurred, a type of peripheral neuropathy that can develop in a few people from taking a vaccine.
The results showed that the vaccine was safe to use as two doses in HIV-positive youth aged 11 to 25 years of age. This was true across the spectrum of CD4 percentages studied, although the number of youth in the <15% group were about one-third the size of the other two groups. The vaccine's safety is good news for protecting the health of HIV-positive youth.
However, when deciding to have this type of vaccine given to a young person, one should take into account the limited effect of the vaccine and its timing during a young person's adolescence. Currently, it is not known if the vaccine provides protection for more than three years after vaccination. It is also not known if the two doses given in this study provide any longer protection than that of the one dose studied in the general public.