COVID-19 rapid tests still work against new variants—researchers keep ‘testing the tests,’ and they pass

By September 2020, simply six months after COVID-19 triggered shutdowns throughout the U.S., it was clear that SARS-CoV-2, the virus that causes COVID-19, had mutated from its unique kind.

The query rapidly arose whether or not existing rapid antigen tests may detect newly rising variants.

Utilizing clinical samples obtained from diagnostic labs all through the U.S. from 2020 to 2023, the Nationwide Institutes of Well being, by way of its Variant Task Force, analyzed the effectiveness of greater than 100 fast antigen check kits on over 300 variants. The overwhelming majority of the kits had been in a position to detect new in addition to prior beforehand recognized variants.

We’re a group of researchers who’ve spent the previous few years researching COVID-19 tests for his or her accuracy and efficiency. We perceive why the general public should still have questions on whether or not these assessments are dependable, significantly as new variants proceed to look.

Listed below are solutions to a few of these questions:

Do these assessments work?

There are two main forms of assessments for the detection of SARS-CoV-2.

The primary, referred to as a RT-PCR test, is greater than 95% correct for detecting the virus. These had been the assessments that the majority Individuals got at drive-through and walk-in testing websites early within the pandemic. The overwhelming majority at the moment are carried out at a physician’s workplace or clinic, although there are some home PCR tests, which generally price 5 to 10 occasions greater than fast antigen assessments.

The opposite kind is an antigen test, generally referred to as a fast check, with an accuracy price of greater than 80%. Most of those assessments are bought over-the-counter at supermarkets and pharmacies.

Speedy antigen assessments are comparatively cheap, can be utilized with out prior coaching and provides fast outcomes, sometimes inside 10 or quarter-hour. One downside is that they’re much less correct than PCR assessments, particularly early in an an infection when there’s much less virus current within the physique.

Regardless of these inherent limitations, our group has demonstrated that these assessments perform as well in 2024 as they did earlier within the pandemic, when completely different variants had been circulating—despite the fact that our preliminary research was accomplished in January 2022. That is as a result of the virus protein detected by antigen assessments has not modified a lot over the past two years, in contrast to different elements of the virus which have undergone many mutations. One other research, which examined the accuracy of fast antigen assessments from 2020 to 2022, found similar results.

That stated, researchers like us proceed to “check the assessments,” each in computer simulations and within the lab, to detect new SARS-CoV-2 variants.

I’ve signs. When ought to I take a check?

When you’ve got signs, take a fast check as soon as possible. In the event you check optimistic, you might be fairly sure that you simply’re contaminated. In the event you’re unfavourable, wait two days and check once more.

This ready interval is necessary as a result of it takes a couple of days for the virus to build up to levels that are detectable by the rapid test. Latest analysis has proven that the time it takes for this to occur is slightly longer with the omicron family of variants in comparison with variants from a couple of years in the past.

I used to be uncovered, however haven’t any signs. When do I check?

In the event you’ve been uncovered to any person however do not have signs, the present advice is to attend four to five days before taking a rapid test. In the event you’re unfavourable, wait two days after which check once more.

In the event you’re nonetheless unfavourable, take a 3rd check two extra days later. That is one of the simplest ways to detect COVID-19 infection without symptoms.

It is also beneficial that you simply take a fast check as shut as doable to the time you are visiting somebody who’s in danger for getting sick, particularly when you suppose you’ll have been uncovered.

When am I contagious?

Most individuals who’ve signs and check optimistic are contagious. In the event you not have signs and are not testing optimistic, it is likely that you’re not contagious.

However there are some exceptions to this normal rule. It is doable to be contaminated, haven’t any signs and be contagious. That is very true early on in an individual’s an infection.

Ought to I swab my nostril or throat?

The perfect recommendation is to comply with the directions that include your check. For antigen assessments within the U.S., this implies taking a swab of your nostril.

Though one research from Denmark reported that antigen tests were more sensitive when a health care provider swabbed the throat, the identical research stated that when an individual swabbed themselves, nostril samples had been extra correct than throat samples. Different research have proven that swabbing the throat was no better than swabbing the nose.

A brand new program funded by the National Institutes of Health and rolled out in late 2023—the Home Test to Treat study—affords free testing, telehealth and remedy for COVID-19 and the flu without leaving home. Thus far, greater than 60,000 folks have enrolled. The research makes use of commercially out there fast assessments and sometimes arrive a couple of days after they’re requested.

For these tens of millions of Individuals who’re unable to journey, are with out insurance coverage, don’t live near a clinic or just do not need to expose others to their signs, this new program may assist save lives.

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