Tat toxoid vaccine is an experimental therapeutic vaccine. Therapeutic vaccines are being developed for use in HIV-infected people to stimulate the immune system and slow the progression of HIV disease. Tat is an HIV protein expressed in relatively small quantities by virus-infected cells which has effects on the immune system which appear to promote HIV infection and limit the immune response to HIV. It is therefore argued that by promoting a specific immune response to Tat, it may be possible to limit the effects of HIV on the immune system.

Tat toxoid vaccine is being developed by a team of Belgian, French and Canadian scientists.

A randomised study of Tat toxoid vaccine in 23 people receiving highly active antiretroviral therapy (HAART) triggered an increase in Tat specific neutralising antibodies and a rise in CD4 T-cell levels. Commonly reported side-effects were injection site reactions, weakness, chills, fever, headache, myalgia, and sweating (Hermans 2003).

Reference

Hermans P et al. Safety and immunogenicity of an HIV-1 tat toxoid vaccine in HIV-1 infected volunteers on HAART. Tenth Conference on Retroviruses and Opportunistic Infections, Boston, abstract 644, 2003.