Use of antibody treatments for Covid-19 has soared in recent months as cases have surged, and evidence suggests the treatments are effective at preventing severe cases of the disease.

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What monoclonal antibody treatments are available?

FDA in November first authorized the use of two monoclonal antibody treatments made by Eli Lily and Regeneron Pharmaceuticals. These treatments use molecules developed in a lab to either replace, improve, or imitate the natural antibodies the body produces to fight infection.

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Since then, Eli Lily's antibody treatment has stopped being used, as it wasn't effective against some variants of the coronavirus, and a separate treatment, made by GlaxoSmithKline, has received authorization from FDA.

How often are these treatments being used?

According to the New York Times, distribution of antibody treatment doses has increased fivefold from June to July. HHS data shows around 75% of that distribution has gone to areas of the country with low vaccination rates.

Alexandra Bowie, a spokesperson for Regeneron Pharmaceuticals, said delivery of its antibody treatment has increased from 25,000 doses per week to 125,000, with around half of those doses shipped to Florida, Texas, Mississippi, and Alabama.

Officials at Intermountain Healthcare in Utah have put together a team of medical professionals who look through lists of recent Covid-19 patients and reach out to those eligible for antibody treatment.

According to Curt Andersen, a family medicine physician and associate medical director at Intermountain, he's seen 70 to 80 patients each day getting antibody treatments during the recent Covid-19 surge.

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Meanwhile, Marcella Nunez-Smith, an adviser to the White House on racial equity in health, said that government "surge teams" sent to states hit hard by Covid-19 have made an effort to increase the use of antibody treatments. As part of this effort, Nunez-Smith said the Biden administration has conducted virtual trainings with doctors and health system officials in Arizona, Nevada, Utah, and Wyoming.

How effective are antibody treatments?

Antibody treatments need to be administered within 10 days of with infection with or exposure to the coronavirus. When used in that timeframe, antibody treatments can significantly reduce a patient's risk of severe Covid-19.

An analysis published earlier this month in Open Forum Infectious Diseases found that high-risk patients who received antibody treatments were 31% less likely to require emergency care or be admitted to the hospital.

According to Brandon Webb, an infectious diseases physician at Intermountain, that means one hospitalization is prevented for every eight patients treated. "That's where you get the most bang for your buck," he said.

Other promising antibody treatments may be on the horizon. On Tuesday, Brii Biosciences released data from a trial of a monoclonal antibody treatment in 800 patients that found it reduced patients' risk of hospitalization and death from Covid-19 by 78%.

And separately, AstraZeneca last week said a study found its new antibody therapy was 77% effective at reducing the risk of developing symptomatic Covid-19.

Among the 5,197 participants in AstraZeneca's trial, more than 75% had comorbidities or chronic diseases, including some conditions that could make Covid-19 vaccines less effective. Two-thirds of the participants in the trial received the antibody therapy, and none of the patients receiving the therapy developed severe Covid-19 or died. Meanwhile, three people in the placebo group developed severe Covid-19, and two died.

'This is not a substitute for [a] vaccine'

While antibody treatments are effective against Covid-19, experts stress that vaccination is still the most effective way to prevent Covid-19.

"This is not a substitute for [a] vaccine, by any means," Christian Ramers, chief of population health at Family Health Centers of San Diego, said.

"It's a backwards strategy," Ramers added. "It's so much better to prevent a disease than to use an expensive, cumbersome, and difficult-to-use therapy. It does not make any medical sense to lean into monoclonals to the detriment of vaccines. It's like playing defense with no offense." (Aleccia, Kaiser Health News, 8/25; Reed, Axios, 8/27; Weiland/Robbins, New York Times, 8/12; Palca, "Shots," NPR, 8/23; Walker, MedPage Today, 8/25; Strasburg, Wall Street Journal, 8/20; Coleman, The Hill, 8/20; Walker, MedPage Today, 8/20)