Immunogenicity of a booster vaccination against tick-borne encephalitis

Abstract

AbstractBackground: Tick-borne encephalitis is endemic in Slovenia, but still less than 10 % of people are regularly vaccinated. The proportion of vaccinated individuals was significantly influenced by obligatory vaccination for all Slovenian military conscripts between 1993 and 2003.Methods: Our study includes 73 men from the Celje region, who were vaccinated with three doses of vaccine against tick-borne meningoencephalitis FSME-Immun® (Baxter), but afterwards they stopped the vaccination for a period of 8 to 16 years. Participating men were serologically tested before and after the first booster dose. We used the enzyme immunoassay Enzygnost®.Results: The result of the analysis was, that with most of the participants the value of titer of antibodies before receiving revaccination was protective (n=67; 91,8 %), while after receiving a booster dose, the protective value was exceeded for all participants who have submitted a second blood sample (n=69; 94,5 %). Geometric mean concentration before the booster dose was 56 U/ml and 314 U/ml after the booster dose.Conclusions: Our study confirmed the long-term protection after primary vaccination with three doses against tick-borne encephalitis with men younger than 50 years, by using enzyme immunoassay. The results support the careful consideration of currently recommended revaccination interval.

Keywords

• tick-borne encephalitis – TBE
• epidemiology
• vaccination
• serological response
• flavivirus.