Effectiveness of the Q fever vaccine: a meta-analysis.

In the Netherlands, the number of notified human Q fever cases showed a steep increase over the last three years and is not expected to disappear in the next few years. Since vaccination might be an option to prevent Q fever cases in the general population, evidence is needed about its effectiveness. We therefore conducted a meta-analysis to determine the evidence base for effectiveness for Q fever vaccination in human populations. We calculated Mantel-Haenszel risk ratios and we used the following formula to calculate the vaccines effectiveness: (1-mhRR) × 100%. Although individual and the pooled estimates showed a high effectiveness of Q fever vaccine, conclusions for the general population cannot be confidently drawn about vaccine effectiveness due to potential flaws in the design of the studies and the selected group of study participants.