Paxlovid shown effective against visits for severe COVID-19


Kches16414 / Wikimedia Commons.

Center for Infectious Disease Research and Policy

Jim Wappes | Editorial Director | CIDRAP News

Pfizer’s antiviral drug Paxlovid was tied to very few COVID-related visits to the emergency department (ED) or hospital, but people in socially vulnerable US regions are less likely to receive it or a similar COVID-19 drug, according to two studies published yesterday in Morbidity and Mortality Weekly Report (MMWR).

Only 0.1% hospitalized

The first study showed that less than 1% of people taking Paxlovid reported to an ED or hospital for COVID-19 within 5 to 15 days.

The drug is a combination of two antiviral medications—nirmatrelvir and ritonavir—and was approved for emergency use by the US Food and Drug Administration (FDA) in December 2021 for people with mild to moderate COVID-19 who are at risk for progression to severe disease.

For the study, researchers with Kaiser Permanente, the Centers for Disease Control and Prevention (CDC), Harvard University, and the University of California, Berkeley, analyzed electronic health record data from Kaiser Permanente Southern California on 5,287 patients 12 years old and older who received Paxlovid from Dec 31, 2021, through May 26, 2022. Among the group, 72.5% had received three or more COVID vaccine doses, and 7.8% were unvaccinated.

The authors said that only 39 of the patients visited the ED (0.74%) and only 6 were hospitalized (0.11%) for symptoms related to SARS-CoV-2 infection. Among these 45 patient, 21 (47%) were aged 65 years or older, and 35 (78%) had at least one underlying medical condition. All hospitalized patients were either elderly or had an underlying condition or both. Two of them died, but none died in the ED group.

Among the 5,287 patients, 57.2% were female, 42.5% were White, and 30.3% were Hispanic. Median age was 61 years, and 56.7% had one or more underlying medical condition.

The authors conclude, “When administered as an early-stage treatment, Paxlovid might prevent COVID-19–related hospitalization among persons with mild to moderate COVID-19 cases who are at risk for progression to severe disease. Additional research is warranted to provide further understanding of the apparent association between Paxlovid and reduced risk for severe COVID-19 illness, including studies with control groups and more precise indicators of COVID-19 illness severity.”

Uptake about half in areas most socially vulnerable

In the second MMWR study, CDC scientists reported that, while the most socially vulnerable ZIP codes have more locations to get COVID antiviral drugs, the people in those areas received the medications less often than those in less vulnerable neighborhoods.

The researchers analyzed data on 1,076,762 prescriptions for Paxlovid or molnupiravir (Lagevrio), another oral COVID-19 antiviral approved by the FDA for emergency use in December 2021. The latter drug is approved for adults only.

They assessed uptake of the drugs by ZIP code areas classified as having low, medium, or high social vulnerability. They note that roughly 20% of US residents live in low–, 31% in medium–, and 49% in high–social vulnerability ZIP codes.

The study period spanned a similar period as the first study: Dec 23, 2021, through May 21, 2022. About 70% of the oral antivirals were dispensed from Mar 7 to May 21, 2022.

From Mar 6 through May 21, the number of antivirals dispensed per 100,000 population increased from 3.3 to 77.4 in low-, from 4.5 to 70.0 in medium-, and from 7.8 to 35.7 in high-vulnerability ZIP codes. The increase coincided with initiatives—like Test to Treat—to increase access to the drugs.

In spite of those efforts, by the end of the study period, dispensing rates in high-vulnerability ZIP codes were only about half the rates in medium- and low-vulnerability ZIP codes. And, as of May 21, 2022, 47.5% of dispensing sites were in high-vulnerability ZIP codes, 32.9% were in medium-vulnerability ZIP codes, and 19.6% were in low-vulnerability ZIP codes.

The authors conclude, “Oral antivirals can provide a critical intervention that can mitigate COVID-19–associated morbidity and mortality. … Additional public health, regulatory, and policy efforts might help to decrease barriers to oral antiviral access, particularly in communities with high social vulnerability.”