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The COVID-19 antiviral pill Paxlovid effectively protects older patients from severe disease, according to seven months of data across a large hospital system. With monoclonal antibodies no longer effective against newer strains of SARS-CoV-2, the findings support prescribing this drug in eligible patients, physician-researchers say.

Paxlovid (nirmatrelvir plus ritonavir) was authorized for emergency use in December 2021. Trials showed an 89% reduction in hospitalization or death among unvaccinated patients who were treated early in the disease process. But the clinical impact of the drug has remained uncertain, according to study lead Ann E. Woolley, MD, MPH, of Brigham and Women’s Hospital in Boston.

Woolley and colleagues gathered data on over 44,000 nonhospitalized adults aged 50 years and older. More than 90% had had three or more COVID-19 vaccine shots, and none had contraindications for nirmatrelvir plus ritonavir.

The investigators looked for hospitalization within 14 days or death within 28 days of a COVID-19 diagnosis. During the study period, 28% of patients received Paxlovid prescriptions. These patients were more likely to be older, have more comorbidities and be vaccinated than the patients who were not prescribed the drug. 

Added protection

Although the overall risk for hospitalization or death for study participants was already very low (1%), Paxlovid reduced that risk by another 44%, the data showed. What’s more, the fewer COVID-19 vaccinations a patient had or the longer the time since their last shot, the greater the protection. Unvaccinated patients, for example, were 81% less likely to experience severe COVID-19 outcomes if they took the antiviral drug. 

The study results help to answer patients’ legitimate questions about the benefits of the new drug. And they also reinforce a system-wide decision to prescribe it, said the researchers, most of whom are physicians or nurses.

“This study … has allowed us to feel, programmatically within the Mass General Brigham system, and clinically within Infectious Diseases, that we were doing the right thing by prescribing Paxlovid to eligible patients,” Wolley concluded in a statement.

Testing needed

The study also underscored the importance of testing, she and her colleagues added. The hospitalizations that did occur during the study were in patients who were not diagnosed until their admission.

“The opportunity to prevent COVID-19 hospitalizations is not there unless people know that they’re positive,” Scott Dryden-Peterson, MD, said. “So we have ongoing efforts to do outreach, make testing available and communicate to the highest-risk patients that they may benefit from Paxlovid or another antiviral treatment option.”

The study was published in the Annals of Internal Medicine.

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