Complications of anti-rabies treatment
It has been shown that purified equine rabies immunoglobulin products cause adverse reactions in 1-6% of vaccinees, even when sensitivity tests are performed prior to their administration. Unpurified anti-rabies sera should be avoided whenever possible.
Repeated inoculations of homogenates of brain tissue may induce immune responses to some neural antigens. In the case of Semple-type vaccine, these neurological complications are attributed to myelin basic protein and some of the ganglioside and phospholipid constituents. Though properly prepared suckling-mouse brain vaccines contain virtually no myelin, neurological complications still occur, but at a much lower rate than with adult nerve-tissue vaccines.
Patients who develop neurological complications from Semple-type vaccines have higher levels of rabies virus-neutralizing antibodies than vaccinees without complications. Dexamethasone is beneficial in managing such reactions, but significantly depresses the virus-neutralizing antibody level, even when a full vaccination schedule is repeated, using a cell-culture vaccine. The eighth report of the WHO Expert Committee therefore suggested that such patients should receive twice the normal amount of cell-culture vaccine when dexamethasone is given.
Cell-culture vaccines and purified duck-embryo vaccine
These vaccines have not been casually associated with serious adverse effects. Mild serum sickness-like and urticarial reactions have occasionally been observed following booster doses of some of these vaccines.