Key messages

• Few studies examine how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tests assist or hinder efforts to prevent illness, hospitalisations, or people dying.

• Due to weak evidence, we’re uncertain if testing helps prevent people from getting sick.

• There isn’t enough research to clearly show the benefits or harms of different types of SARS-CoV-2 testing for preventing illness, hospital stays, or deaths.

What is SARS-CoV-2?

A new virus called SARS-CoV-2 was discovered in China in December 2019. By May 2024, it had infected 775 million people with COVID-19, and more than seven million people had died. Testing people for the virus can help healthcare workers identify when more people are becoming ill, allowing them to act quickly to keep others safe.

What did we want to find out?

We looked at how well different SARS-CoV-2 testing methods work to help stop people from getting sick, going to the hospital, or dying. We also wanted to find out if SARS-CoV-2 testing was associated with any unwanted effects.

What did we do?

We looked for studies that compared different SARS-CoV-2 testing strategies for people with and without symptoms, examined what the studies found, and summarised the results. We presented the main comparisons that we decided in advance. We also rated our confidence in the evidence, based on things like how the studies were done and how many people took part.

What did we find?

We found 21 studies, with 13,312,327 people, that examined the benefits and harms of various SARS-CoV-2 tests. However, only four of these studies, with 190,821 people, measured results that we were interested in.

Main results

One study, conducted in a long-term care facility in Israel, measured the effect of weekly SARS-CoV-2 tests on the number of people who were admitted to hospital or who died for the comparison: testing strategy versus no testing or standard care or usual practice. The study did not measure COVID-19 cases avoided, or serious unwanted effects related to testing. No studies measured these results for the comparison: testing strategy versus another testing strategy.

Benefits and harms of testing strategy versus no testing or standard care or usual practice

We are very uncertain about the results on the number of people admitted to hospital and deaths, based on the one included study that looked at the effect of weekly SARS-CoV-2 testing compared to no testing.

What are the limitations of the evidence?

We found a few studies. The evidence we examined from two results—comparing testing to no testing—wasn’t very strong because it was from a single study, the study had problems with how it was done, and it didn’t align well with the question. The results might not be completely fair or accurate because other factors got mixed in, and how results were measured could have been faulty. Further research is likely to change our results.

How up to date is this evidence?

The evidence is up-to-date as of 07 October 2024.