LONDON (Reuters) - A British trial of how risky cultural and sporting events are for transmission of the coronavirus found no substantial outbreaks of COVID-19 although the findings were based on a low number of test completions, government researchers said.
Britain has conducted a pilot scheme to test audiences at live events from soccer matches to raves and concerts, some of them indoors, to see if they can be held with full crowds.
The researchers said in a report published on Friday that "no substantial outbreaks were identified by public health teams and their surveillance systems around any of the events."
Across all the events, which were attended by more than 50,000 people, only 15% of participants returned the two tests they were asked to do - before and after the event - and of them 28 positive cases were found.
Eleven of those cases were considered to have potentially been infected before the event they attended while the remaining 17 could have been infected at the event or afterwards, the researchers said.
They said the low proportion of people returning both tests meant the results should be interpreted with "extreme caution."
On Thursday, concert managers and theatre producers joined forces to call on the government to explain why it was keeping restrictions on audiences in place as part of a delay to the lifting of the last social-distancing rules.
Prime Minister Boris Johnson earlier this week pushed back the so-called Step 4 of removing coronavirus restrictions until July 19 from June 21 because of the spread of the more infectious Delta variant.
(Reporting by William Schomberg. Editing by Andrew MacAskill)