Date	Event	Description
29 November 2012	New citation required but conclusions have not changed	Seven placebo‐controlled trials, which were previously excluded because there were no data suitable for our meta‐analyses, have been included (Table 7). Their exclusion was inconsistent with the Methods section. This change did not result in changes to our conclusions (Abbott 1968; Asfora 1977; Briggs 1984; Elliot 1973; Regnier 1968; Scheunert 1949; Tebrock 1956). In previous versions 'prophylactic' was used to indicate the trials in which vitamin C was administered every day. 'Prophylactic' is relevant when measuring the incidence of episodes. However, that term is confusing when measuring the duration of episodes that occur during the trial. Therefore, in the 2012 version, we changed to the term 'regular supplementation' to indicate trials in which vitamin C was administered every day.
29 November 2012	New search has been performed	Searches conducted. We included one new trial (Constantini 2011a; Constantini 2011b) and excluded two new trials (Maggini 2012; Schmidt 2011).
2 February 2010	New search has been performed	No new trials identified in this updated search. However, one trial with marathon runners was excluded because of the high level of drop‐outs and severe bias in the drop‐out rate between the study arms (Himmelstein 1998b). We excluded the Audera 2001c trial arm because flavonoids were administered in addition to vitamin C. We restricted the review to purely vitamin C comparisons. The conclusions remain unchanged since the last update (Douglas 2007).
13 November 2009	Feedback has been incorporated	Feedback comment and reply added.
13 June 2008	Feedback has been incorporated	Feedback comment and reply added.
12 June 2008	Amended	Converted to new review format.
23 July 2007	Feedback has been incorporated	Feedback added.
15 November 2005	Feedback has been incorporated	Feedback added.
27 August 2004	Feedback has been incorporated	Feedback comment added.
11 June 2004	New citation required and conclusions have changed	Substantive amendment.