10 diciembre, 2021

We need to normalize rapid testing for unmasked gatherings

We’re getting into the cold months when more people will be gathering indoors and respiratory illnesses like COVID-19 thrive. Requiring some proof of immunity is becoming more standard and widely accepted, and it remains a generally good rule. And the new boosters, now finally available to all adults, will help with this immunity.

But immunity alone has proven insufficient to protect a gathering, particularly in the new environment of more aggressive and contagious variants like delta and omicron. Breakthrough infections — those in people who are already immunized — are on the rise. A stark demonstration of this is the increase in vaccinated people testing positive at the Israeli national airport where testing is required.

Despite the earlier beliefs that breakthrough infections were generally mild (other than in immunocompromised people), they are becoming more severe as the variant landscape changes. And breakthrough infections, even if mild, can derail your life for a period of time, restrict your travel, cause the virus to continue to spread, as well as lead to long-term repercussions (known as long-COVID).

For some gatherings — like going to the theater, getting on an airplane, riding mass transit — we can require masks, and masks help keep things relatively safe. There seems to be reasonable support for such mask requirements. Even in places like Texas, where vaccine and mask debates have been particularly dramatic, a new study shows the majority support mask mandates.

But for many gatherings — particularly those that involve eating and drinking — masks are not feasible. These gatherings are far riskier, and will likely be the main source of rising cases during the coming months. Of course, nobody with suspicious symptoms should attend a gathering until they are fully evaluated and cleared by a medical provider.

However, the more insidious risk comes from the fact that people can harbor the virus without symptoms, unaware, then attend a gathering and potentially spread it to everyone there. One good way to mitigate this risk is to require rapid antigen testing at the door, or as close to the time of the gathering as possible. With the current quality and availability of at-home rapid testing, this is quite feasible, and something we should normalize.

There are two broad categories of diagnostic tests currently available. To be clear, we are not talking about antibody blood tests that tell you if your body has seen the virus or vaccine and reacted to it. We are talking about nasal tests to see if you are currently shedding the virus. RT-PCR testing is the most sensitive of the two categories: using the PCR amplification process, it can detect even tiny amounts of virus.

The logistical problem with this test is that it requires a lab to run, so home testing is currently not possible. The medical problem is that it takes time to run the test, and most labs can take up to three days to give you a result. This means that if you want everyone RT-PCR tested for your dinner party, you need to send them to a lab three days before your party — and the negative test they bring can only tell you they were negative three days ago, and not whether they’re virus-free three days later when they walk into your party.

Rapid antigen testing is less sensitive, which means you have to be shedding more virus for a positive test. While that may seem problematic, it is quite likely that if you are shedding only a tiny amount of virus (that would result in a positive RT-PCR test but a negative rapid antigen test), you are not shedding enough to infect others around you — especially if they also have immunity. Also, agreement between rapid antigen tests and RT-PCR are actually quite high. No test will ever be perfect, and no paradigm will ever ensure that a gathering during a pandemic is fully safe, but rapid antigen tests are appealing because they are very good, very fast and do not require a lab. And unlike the RT-PCR test that you had to do three days before the gathering, you can do a rapid antigen test at or very close to the time of the gathering, giving you a more timely measure of whether you are virus-free.

Putting a cotton swab in your nose, sticking it into a testing kit, and waiting 15 minutes for a result is pretty simple. Of course, the biggest barriers to rapid testing for unmasked gatherings are cost and availability. Even at $10 to $15 per test today, this can add substantially to the cost of an evening out, and for some this will be cost-prohibitive.

But these barriers will hopefully be addressed soon: President Biden just announced plans to substantially increase support for rapid antigen testing, including medical insurance reimbursement for home tests and distribution of 50 million free tests for those without insurance. This reinforces the September commitment of $2 billion to accelerate the production of rapid tests: according to the White House statement, “we are on track to quadruple the supply of rapid at-home tests that we had in late-Summer.” Implementation of this plan needs to happen now.

Showing that you are free from COVID-19 at the time of an unmasked gathering is something we should be able to normalize. There is already a precedent that nobody should attend a gathering who has a fever or is sneezing and coughing. By monitoring your symptoms, you are reassuring yourself that you are safe to be around others, and by knowing they will observe your symptoms if you have them, others can be reassured that you’re safe to be around.

However, this precedent makes sense if viruses are only spread by people with symptoms. Since this virus and all of its variants can spread without symptoms, we need another way to reassure everyone around us that we’re not shedding virus, and testing is the only way to do so. In fact, since monitoring our own symptoms is insufficient, testing is the only way that even we can know if we’re safe to be around others. And we should certainly want to know if we’re safe to be around others.

Créditos: Comité científico Covid

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