Analysis
The Newcastle-Ottawa-Scale was used to assess the risk of bias in non-randomized observational studies 14. Risk of bias in randomized controlled trials was assessed using the Cochrane Handbook “Risk of Bias” assessment tool 15. Risk of bias was assessed at the outcome level.
The primary summary measure was percentage of persons experiencing an adverse reaction, as well as the range in which a reaction occurred in the studies included. No meta-analysis and further summery measures were planned due to the expected large heterogeneity of the studies.