One-year follow-up evaluation of approved Subolesin anti-tick vaccine in Uganda.

After approval of the Subolesin-based anti-tick vaccine in Uganda, we completed a one-year follow-up evaluation study. The results showed significantly 2.1-5.0-fold higher anti-SUB IgG antibody titers in vaccinated cattle in Mbarara and Maruzi with vaccine effectiveness higher than 95 %. In Mbarara, total number of ticks were 0.8-fold lower in vaccinated cattle with a negative correlation tendency between anti-SUB antibody titers and tick counts. The CCHFV-seropositive cattle significantly decreased in 40 % in SUB-vaccinated animals with a significant positive correlation between CCHFV-seropositive cattle and the total number of ticks per animal and a negative correlation tendency between anti-SUB antibody titers and CCHFV-seropositive cattle. A boosting vaccine dose yearly after primary vaccination with three doses is sufficient to maintain protective antibody titers against ticks and tick-borne diseases affecting human and animal health. These results are relevant for implementation of anti-tick Subolesin-based vaccines in Uganda and other countries in Sub-Saharan Africa.