Testing plays a vital role in humanity’s technique to mitigate the consequences of widespread COVID-19 infection. Nonetheless, given multiple options for testing and the emergence of the highly contagious Omicron variant, how do we decide which test to make use of?

A study led by Osaka University recently found that the sensitivity of rapid antigen tests (RATs) for the Omicron variant of COVID-19 compared with polymerase chain response (PCR) tests was 0.63 and that this value was not affected by the duration from the onset of symptoms to testing. This finding suggested the likelihood that, as with previous variants, frequent testing using RATs for the Omicron variant of COVID-19 still outperformed infrequent testing using PCR tests. That is despite RATs requiring a bigger amount of the virus to be present to return an accurate positive result (i.e., lower sensitivity) compared with PCR tests. Nonetheless, RATs are also cheaper and produce results quickly.

Prior to the emergence of the Omicron variant, frequent testing using RATs was known to be a greater strategy than infrequent testing using PCR tests. RATs detect infection early, which allows for swift isolation of people who’re infected, thus stopping the spread of COVID-19.

The sensitivity of the RATs was vital information for establishing an efficient testing system.”

Michio Murakami, Lead Writer

Nonetheless, when the Omicron variant of COVID-19 emerged, the sensitivity of RATs for this variant was called into query, particularly in the course of the crucial early stages of infection. If the sensitivity of RATs is low, then the benefits of RATs can be negated, requiring a rethink in testing strategy for combating the spread of infection.

Subsequently, the researchers directly compared the sensitivity of RATs and PCR tests in cases of COVID-19 infection known to be brought on by the Omicron variant.

“We used data collected from players and staff members of clubs belonging to the Japan Skilled Football League,” explains co-author Seiya Imoto of The University of Tokyo. “This organization carried out RATs and PCR tests in the identical person on the identical day, making this data set uniquely useful to evaluate the comparative sensitivity of those tests.”

The outcomes showed that sensitivity was not related to the duration of the onset of symptoms to testing in each symptomatic and asymptomatic cases. The researchers also found the sensitivity of RATs for the Omicron variant to be high enough to suggest the likelihood that, when combined with other studies on the connection between sensitivity or frequency of testing and its effectiveness in stopping infection, frequent testing using RATs, versus less frequent testing using PCR tests, continues to be the best plan of action.

The study findings form a crucial knowledge base for assessing the effectiveness of a testing system using antigen qualitative tests. Nonetheless, because the Omicron variant is more infectious than previous variants and has a shorter incubation time, the researchers indicate that further testing and modeling are required to find out probably the most effective testing protocol.

Source:

Journal reference:

Murakami, M., et al. (2023) Sensitivity of rapid antigen tests for COVID-19 in the course of the Omicron variant outbreak amongst players and staff members of the Japan Skilled Football League and clubs: a retrospective observational study. BMJ Open. doi.org/10.1136/bmjopen-2022-067591.