Measles and MMR vaccines are contra-indicated in immunocompromised persons. The literature provided with MMR vaccine by one manufacturer state "Tresivac (MMR vaccine) may be used in children with known or suspected HIV infection. Although the data are limited and further studies are being encouraged there is no evidence to date of any increased rate of adverse reactions using this or other measles, mumps and rubella vaccines in symptomatic or asymptomatic HIV infected children. The vaccine should be avoided in other cell mediated immunodeficiency states." Which vaccines should not be administered to HIV infected persons?

There are two kinds of issues that worry us when we consider immunization in the immunodeficient (or potentially immuno-deficient) child. The first issue is concerning the adequacy of immune response resulting in protection from disease when it is needed. The second issue is regarding the possibility of disease caused by the live organisms in various vaccines. Since the question is focussed around MMR vaccine, the second issue is the more relevant issue for consideration in my reply and the cause of immunocompromise is HIV infection.

The immune deficiency caused by HIV infection is both gradually progressive and life-long. Very early in the course of HIV infection, the immune system is only minimally affected and for all practical purposes it is functionally normal (or near normal). In due course, the cell-mediated arm of immunity is more severely affected than the humoral arm. However, since the CD4 (T helper) cells are involved in HIV infection and disease, the progressive immune deficiency affects both arms of immunity.

Live vaccines such as BCG and Measles vaccine have been reported to cause disease due to uncontrolled dissemination in severely immunocompromised persons with HIV infection. To the best of my knowledge, such adverse events have not been reported with the administration of OPV, Varicella vaccine or live oral typhoid vaccine. In the case of children who are in the early phase of HIV infection, clinically classified as "asymptomatic", both BCG and Measles vaccine are well tolerated, without any serious adverse events. For these reasons, recommendations regarding immunization will be considered separately for the asymptomatically HIV infected and for those with evidence of HIV disease (or AIDS).

The WHO has recommended all EPI vaccines (including BCG and Measles vaccine, as well as OPV) for infants born of HIV positive mothers, whose HIV infection status has not been determined and for known HIV infected children who are as yet asymptomatic. This guideline would apply to MMR also. In the United States OPV is not allowed in these children, more for theoretical reasons than from experience; the availability of IPV makes this option quite feasible.

The WHO does not recommend BCG in children with symptomatic HIV infection. Both under WHO EPI and in the United States, Measles vaccine (or MMR) is allowed even in symptomatic stage of HIV infection (except in the terminal phase), so as to prevent serious and life threatening wild measles virus disease. Experience with Varicella vaccine is limited; hence as a cautionary measure it is not given to known HIV infected children in the US. Since non-live typhoid vaccines are available, perhaps the same approach is possible with typhoid vaccines; in other words, perhaps we ought to avoid live oral typhoid vaccine in HIV infected children, unless sufficient data on safety emerges.

T. Jacob John,
Emeritus Medical Scientist (ICMR),
439, Civil Supplies Godown Lane,
Kamalakshipuram,
Vellore 632 002, India.
E-mail: [email protected].