PERSISTENCE OF ANTIBODIES IN CHILDREN AFTER INTRADERMAL OR INTRAMUSCULAR ADMINISTRATION OF PREEXPOSURE PRIMARY AND BOOSTER IMMUNIZATIONS WITH PURIFIED VERO CELL RABIES VACCINE

Background. The use of intradermal lid) injections of purified Vero ce ll rabies vaccine (PVRV) for preexposure prophylaxis has not been well -established. We studied the safety and immunogenicity of id and intra muscular (im) PVRV injections for primary and booster preexposure immu nizations. Methods. One of two rabies preexposure PVRV regimens compri sing three doses of either 0.1 mi id or 0.5 mi im administered during 28 days was assigned at random to 190 school children. One booster dos e was given 1 year later either id or im, according to their initial r andomization group. Serologic results were available from 155 (82%) ch ildren at 1 year after primary immunization and 118 (62%) children at 2 years after booster. Results. Although children vaccinated id had si gnificantly lower rabies-neutralizing antibody titers after primary im munization as well as after booster than children vaccinated im (P < 0 .001 for all time points), there were no significant differences in th e percentages of children with adequate titers (greater than or equal to 0.15 IU/ml) between the id and im groups after both primary and boo ster immunizations. Mild local reactions were more frequent after id v accination. Mild or moderate systemic reactions were infrequent and si milar after id and im vaccinations. Fever and headache were reported b y less than or equal to 6%. The reactions after booster were not diffe rent from those of postprimary immunization. Conclusions. Purified Ver o cell rabies vaccine appears to be safe and immunogenic for primary a nd booster preexposure immunizations. An id PVRV preexposure regimen s hould be useful especially for rabies-endemic countries with low per c apita income.