Will rapid-antigen testing at events work?

Updated: Mar 2, 2021

Swallow Events, a UK based event management agency, is offering COVID-19 screening services for event organisers. The company will provide pop-up testing facilities staffed with healthcare workers and rapid antigen tests. However, experts are questioning the effectiveness of these rapid antigen testing on asymptotic people.

Swallow Events plans to use rapid antigen tests supplied by the Swiss company Roche for their screening services. According to Roche, their tests are CE approved, within guidelines provided by the MHRA (UK's Medicine and Healthcare products agency) and very effective. Rapid antigen tests only take 15 - 30 minutes, instead of the average 24 hours the most commonly used RT-PCR tests take. They also don't require a lab to produce results, meaning they can be used in the field. In theory this would mean they could be used for events. But according to the American Centers for Disease Control and prevention (CDC) there is not enough data to be sure if these tests work on people who are asymptomatic. This is when someone is carrying the virus but not showing symptoms. These asymptotic people are precisely the kind of people that will show up to an event thinking they are not carrying the virus, because they don't have symptoms. If a rapid antigen test then tells them everything is fine, they will likely spread the virus around the festival grounds. Which can lead to a so called "super spreader event".

Another thing to keep in mind is that no test is 100% effective in the field, even though the Swallow events website claims otherwise. The Roche test has a specificity of 98.84%. This means that in 1,26% of the cases the test gives a negative, even though the person tested is carrying the virus. On an event with 10.000 people, this could theoretically mean about a hundred people with COVID-19 pass through. In their paper about the rapid antigen tests, Roche states they believe the people with false negatives already passed the infectious stage and can no longer infect other people. But this is not certain and we should be careful to assume we can just test everyone at the gate and then have a party without any restrictions.

Having healthcare workers perform the test will likely insure they are being done properly, lowering the risk of false negatives. But it might not be the best idea to take healthcare workers out of an already understaffed NHS to spend their days testing for Covid-19 at events. There has been a shortage of nurses and other healthcare workers for a number of years and this has only gotten worse due to the COVID-19 pandemic.


Sources: Sallow Events | CDC | Guardian | Roche