p>The yellow fever vaccine is effective and safe in HIV-positive individuals with a CD4 cell count above 200 cells/mm3, according to a retrospective French study published in the March 25th edition of AIDS.
Yellow fever is a potentially fatal mosquito-borne viral infection which can be effectively prevented with the yellow fever 17D vaccine. However, as this is a live-attenuated vaccine, there have been concerns that it cannot be safely given to HIV-positive individuals, as there is a theoretical risk of prolonged yellow fever virus replication, which could infect the brain and cause organ damage. In addition, a study in asymptomatic HIV-positive children suggested that the yellow fever vaccine might not provide effective immunisation.
In 2002, however, it was recommended in the US that HIV-positive individuals with CD4 cell counts above 200 cells/mm3 should be vaccinated if travelling to Africa or South America ,where yellow fever is endemic.
French investigators conducted a retrospective study involving twelve HIV-positive individuals who received the 17D yellow fever vaccine prior to travel between 1995 and 2002, to see if the vaccination produced an effective antibody response and was well tolerated.
Nine of the patients were women, and the mean age was 39 years. Two individuals had been diagnosed with an AIDS-defining illness prior to being vaccinated against yellow fever. At the time of vaccination, mean CD4 cell count was 561 cells/mm3, and mean viral load was 5,477 copies/ml. Nine patients were taking antiretroviral therapy at the time of immunization, and five had a viral load below 200 copies/ml.
All the patients developed a good immune response to the vaccine, with a mean yellow fever neutralizing antibody titre of 1/40. CD4 cell counts and viral load tests were available for ten patients three months after the use of the vaccine. There was no significant change in CD4 cell count (p=0.6), or viral load (p=0.2) from baseline, and all five patients who had an undetectable viral load at baseline remained undetectable after receiving the vaccine.
One patient developed a transient fever and sore throat five days after receiving the vaccine. No serious adverse events were recorded.
The investigators conclude yellow fever vaccine “appears to be safe and effective in HIV-infected patients with CD4 cell counts above 200 cells/mm3, even if they have previously developed AIDS or if their viral load is above 10,000 copies/ml.”
Further information on this website
Vaccinations and immunisations - overview
Tattevin P et al. Yellow fever vaccine is safe and effective in HIV infected patients. AIDS 18: 825-827, 2004.