Adult US COVID-19 patients who received the antiviral drug Paxlovid within 5 days after diagnosis had a 51% lower hospitalization rate than nonrecipients, according to an observational study yesterday in Morbidity and Mortality Weekly Report.
Researchers from the Centers for Disease Control and Prevention (CDC) and Epic Research in Verona, Wisconsin, analyzed the electronic health records of 699,848 high-risk COVID-19 outpatients eligible to receive nirmatrelvir-ritonavir (Paxlovid) amid Omicron variant predominance, from Apr 1 to Aug 31, 2022. Of that number, 28.4% received Paxlovid within 5 days after diagnosis.
Many patients had previous COVID-19 infections or were vaccinated against the virus. A total of 92.4% of Paxlovid recipients had at least one chronic condition.
In the 30 days after diagnosis, 0.75% of the total population were hospitalized, 63.3% of them people 65 and older. Of the 198,927 Paxlovid recipients, 0.47% were hospitalized, compared with 0.86% of 500,921 nonrecipients.
Among the 5,229 hospitalized patients, 17.8% received Paxlovid within 5 days of diagnosis. A total of 211 in-hospital deaths occurred, for a death rate among Paxlovid recipients of 0.01%, compared with 0.04% of nonrecipients.
Paxlovid was tied to an overall lower hospitalization rate within the next 30 days than that of nonrecipients (adjusted hazard ratio [aHR], 0.49). aHRs among recipients were lower in recipients of at least three doses of mRNA vaccine (0.50), in all age-groups (18 to 49 years aHR, 0.59; 50 to 64 aHR, 0.40; and 65 and older aHR, 0.53). In the total population, Paxlovid was linked to a lower rate of all-cause hospitalization (aHR, 0.45) and hospitalization for acute respiratory illness (aHR, 0.48).
The authors noted that the initial Paxlovid clinical trial, which showed an 89% reduction in severe COVID-19, was conducted in unvaccinated, COVID-naïve people before Omicron.
"The ease of oral administration, short duration of therapy, and lower likelihood for resistance make Paxlovid a useful antiviral," they wrote. "Paxlovid should be offered to eligible adults irrespective of vaccination status, especially in groups with the highest risk for severe COVID-19 outcomes, such as older adults and those with multiple underlying health conditions."