Jilich et al.
Immunogenicity and safety of rapid vaccination against tick-borne encephalitis in HIV-1 infected persons
Epidemiol. Infect. 2021;149:e41. doi:10.1017/S0950268821000194

The two licensed TBE vaccines based on the European subtype (Neudörfl strain: FSME Immun and K23 strain: Encepur) are highly immunogenic in healthy vaccinees and have an acceptable safety and tolerability profile.

Only a few data about the performance of TBE vaccines are available in HIV-1 infected persons.

A Czech team has carried out a clinical study to evaluate the immunogenicity and safety profile in 28 HIV-1 infected persons (medium age 36.4 years) using the rapid immunization scheme (day 0, 7, 21 and booster dose on day 365) of the K23-based TBE vaccine. IgG antibodies were measured by an ELISA based on K23 antigen and, if lower than 50 VIEU/ml, samples were considered negative.

All participants were seronegative prior to the first injection on day 28 (one week after the third injection), protective IgG concentrations were found in 35.7% of the 28 participants and responders had antibody titers ranging from 135.5 to 1472 VIEU/ml.

On day 60, protective TBE IgG antibodies were found in 39.3% of participants, on day 180 in 25%, and on day 365 in 21.4%. One month after the booster on day 365, 96.4% of the vaccinees had protective antibody titers, and the proportion of protected vaccinees decreased to 71.4% on day 730.

The authors concluded that TBE vaccination using the rapid immunization scheme does not ensure a satisfactory onset of early protection in most HIV-1 individuals (compared to historical data in healthy individuals) and should not be considered reliable in routine practice.

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