[Investigation of antibody levels following rabies vaccination in the subjects who were biten by animals].

Rabies is still an important public health problem in developing countries. Vaccination against rabies should be initiated as soon as possible following the suspicious bite. It is not yet clear whether previously vaccinated people should be re-vaccinated in case of re-exposure to rabies virus. In this study it is aimed to determine the antibody titer in sera of vaccinated people and also to evaluate the relation between the antibody titer and number of vaccination. The study group consisted of 186 persons (60 female, 126 male) aged between 2-90 years (mean: 35.7 years) and who were admitted to Manisa State Hospital Rabies Follow-up Center, Turkey. Hundred and thirty five of the cases were vaccinated according to the programmes advised by WHO's reference protocol for post-exposure rabies vaccination. However, vaccination was discontinued for 51 of the cases since the follow-up of the suspicious animal revealed that it was not rabid. Five-dose vaccination programme (on days 0, 3, 7, 14, and 30) was applied to 20 cases and four-dose programme (on days 0, 2, 7, 21) was applied to 115 cases. HDCV vaccine was applied as intramuscular injection and after 3-36 months following vaccination, rabies specific neutralizing IgG antibody titers were determined by using a commercial ELISA kit (Platelia Rabies II, BioRad, France). While the titer of IgG antibodies were within the protective limits (positive, > or = 0.5 IU/ml) in 116 (62.4%) of the 186 cases who were given two or more doses of HDCV, the titer was below the protective level (negative) in 70 (37.6%) of the cases. Although the rates of IgG positivity in two and three dose vaccine applied group (54.5% and 55.1%, respectively) were lower than the rates in four and five dose applied group (64.3% and 70%, respectively), the difference was not statistically significant (p> 0.05). These results denoted that the rate of protective antibody positivity was low (70%) even in full programme vaccinated cases and this might be attributed to age of the person, the length of time after vaccination, number of vaccinations and storage/transport condition of the vaccine. Thus in case of reexposure of vaccinated people to rabies virus, it is recommended to check the anti-rabies antibody titers if possible or to re-vaccinate those people with a history of prior vaccination exceeding one year since there is high probability of low level of protective antibodies.