Two new antiviral pills — both of which have shown promise in preventing hospitalisations and deaths in people at high risk for severe COVID-19 — are currently being reviewed by the U.S. Food and Drug Administration. One of the drugs, developed by the pharmaceutical company Merck, could receive emergency authorisation as early as this week. Another, made by Pfizer, is likely to be close behind. Although the drugs are not a replacement for vaccination, they could drastically expand access to treatments for a disease that is still killing 1,000 Americans a day. But the pills, which interfere with viral replication, are designed to be taken as soon as possible after symptoms appear. Fully harnessing their benefits is likely to depend upon timely, accurate COVID testing — something that the United States has struggled to achieve since the beginning of the pandemic. At times, especially in the summer and fall of 2020, getting tested for the virus has required an hours-long wait in line, followed by a week-long wait for results.

Much has improved since then, and supply of the new drugs is likely to be extremely limited initially. Merck, for instance, is expected to supply enough of its drug to treat slightly more than 3 million Americans before February. Still, the new antivirals could put America’s still shaky testing infrastructure to the test, experts said. And officials will need to ensure that quick, affordable virus tests are available in the communities that have been especially hard hit by COVID. “People have to want to get tested, and we have to be able to get tests to people quickly,” said Dr. David Boulware, an infectious disease specialist at the University of Minnesota. “Can that happen?” Currently, the most effective treatments available for COVID in the U.S. are monoclonal antibody drugs, which bind to the virus and stop it from infecting cells. But these treatments are typically administered intravenously by health care workers. This can pose logistical challenges both for hospitals, many of which are overburdened and short-staffed, and for patients, who may not be able to get to clinics or infusion sites. The new antivirals are different. “You could potentially pick up your prescription and go home,” said Dr. Michelle Barron, the senior medical director of infection prevention and control for UCHealth, a health care system in Colorado.

The Merck and Pfizer treatments, which involve taking 30 or 40 pills over the course of five days, should be given early in the course of infection, while the virus is replicating quickly. In clinical trials, which enrolled only unvaccinated people at high risk for serious disease, Merck’s regimen reduced the risk of hospitalisation and death by about 30 percent when given within the first five days of symptoms, while Pfizer’s cut those risks by 89 percent when given within the first three days of symptoms.

Replicating these results in the real world will require people to act swiftly, perhaps at the first sign of the sniffle. “It starts with the public education such that when people start to have mild symptoms, early in the course of their illness, they think, ‘This might be COVID-19, and I should get a test,’” said Alyssa Bilinski, an expert on public health policy at Brown University. “Then, of course, we have to have access to tests that have to ideally be affordable. Then people need to get their test results back and they need to get them back quickly.”

She added, “All of this needs to happen within three to five days.” It is not yet clear whether officials will require patients to take a certain kind of COVID test before the drugs are prescribed. In Britain, which already authorised the Merck pill, regulators specified only “a positive SARS-COV-2 diagnostic test.”

Emily Anthes is a journalist with NYT©2021