ba‐Liese 2013.

Study characteristics
Methods	Case‐control study ‐ Munich, Bavaria, Germany
Participants	Children at least 1 year of age, born on or after 1 July 2003, residing in Germany Cases: suspected clinical varicella disease at the time of study entry Control: children matched by age and paediatric practice, fulfilling the same criteria as cases but without history or present clinical diagnosis of varicella
Interventions	Cases were classified as vaccinated varicella cases if they had received OKA/GSK, OKA/Merck, or the combined MMR‐OKA/GSK vaccine at least 28 days before varicella onset. Controls were classified as vaccinated if they had received OKA/GSK, OKA/Merck, or MMR‐OKA/GSK vaccine at least 28 days before varicella onset in the matched case.
Outcomes	Laboratory or clinically confirmed
Funding Source	Pharmaceutical industry
Notes	Ascertainment of the vaccination status by practice record and vaccination cards
Risk of bias
Bias	Authors' judgement	Support for judgement
CCS ‐ case selection	Low risk	Adequate ‐ laboratory‐confirmed ‐ representative series of case
CCS ‐ control selection	Low risk	Adequate ‐ community
CCS ‐ comparability	Low risk	Adequate ‐ matched by age and paediatric practice
CCS ‐ exposures	Low risk	Adequate ‐ secure record‐ vaccination card
Summary Risk of Bias assessment	Low risk	We had concerns regarding multiple domains such that our confidence in the result is substantially lowered.