LONDON, May 21 (CNA) - Only 15 people out of almost 60,000 who attended nine pilot events for mass gatherings have since tested positive for coronavirus, British health officials said Friday (May 21).

The government allowed limited crowds at the events - including two FA Cup games, the World Snooker Championship and the Brit Awards - over recent weeks to assess their impact on COVID-19 transmission.

The country has since March been gradually easing its strict lockdown, with 22,000 football fans permitted inside Wembley Stadium last weekend for the FA Cup final.

Officials are now working to trace just 15 people to have tested positive following the nine official test events, with that level of infection in line with case numbers for the broader population.

"The aim of our world-leading events research programme is to examine the risk of COVID-19 transmission at large events and explore how crowds can be welcomed back in bigger numbers safely," a government spokesman said.

"The pilots have been designed in a scientifically controlled way to reduce the risk of transmission for attendees.

"We are working closely with NHS Test and Trace to ensure everyone can be traced following a positive test," the spokesman added, referring to Britain's state-run National Health Service.

The United Kingdom has been one of the hardest-hit countries in Europe by the pandemic, but has been able to ease lockdown measures in part thanks to a highly successful vaccination campaign.

The government is hoping to lift remaining restrictions on Jun 21, but doubts have emerged after numerous spikes in the Indian variant of the virus across the country.

Prime Minister Boris Johnson is expected to make an announcement on the next stage of the relaxations next week.