Date	Event	Description
11 June 2020	New citation required but conclusions have not changed	The included trial publication (secondary analysis of a previously included trial) did not change the conclusions.
11 June 2020	New search has been performed	Two new review authors joined the team. One new review author (VL) conducted systematic searches for randomised controlled trials and controlled clinical trials to update the review. The other new review author (JHLdS) independently assessed risk of bias, determined the certainty of the evidence using the GRADE framework, and performed data extraction of all eligible studies. Any discrepancies in results for this update were discussed with a second review author (RPV) and where needed with a third review author (RAMJD). We changed some of the GRADE assessments in this review update. On reflection, we felt that our GRADE assessments were incorrect in the last publication; our confidence in the effect estimates for some of the outcomes was too optimistic in previous versions. We updated the searches (March 2019 to June 2020) and included one new trial publication (Karppinen 2019) as a secondary analysis of Vesikari 2016 (FinIP vaccine trial). No further studies were excluded. We did not identify any ongoing studies.