The anti-viral treatment Paxlovid received FDA emergency use approval in December 2021 to reduce the likelihood of severe COVID-19 disease. In the U.S., patients are eligible for Paxlovid if they are determined to be high risk for complications from COVID-19.1 We studied 567,560 patients who could have received Paxlovid treatment between March 1, 2022, and August 1, 2022. Of these, 146,256 received Paxlovid and 421,304 did not. In an unadjusted analysis, patients who did not receive Paxlovid were two times more likely to be hospitalized and four times more likely to die compared to those who did receive Paxlovid (Figure 1).
When stratified by age, patients aged 65+ are 2.5 times more likely to be hospitalized if not treated with Paxlovid (Figure 2).
As previously published, having a full series of COVID-19 vaccination and a booster decreases risk of hospitalization and death from COVID-19. Figures 3 and 4 evaluate whether being treated with Paxlovid adds benefit to patients already vaccinated with a primary series and/or boosted. Figure 3 includes patients with a complete COVID-19 series without booster and Figure 4 includes patients with the complete series and a single booster. At the time of this study, the EUA allowed only immunocompromised patients to be eligible for two boosters. There were too few patients with two boosters to meaningfully study a difference in outcomes for that group.
In our unadjusted analysis, for patients aged 50+ who have received a complete primary series of a COVID-19 vaccination with or without a booster, there is a statistically significant difference in the hospitalization rate for those who received Paxlovid and those who didn’t. This remains true regardless of vaccination status. We did not evaluate the effect of race and ethnicity or other potential confounders in this analysis. Patients aged 40-49 show reduced hospitalization rates, but when broken down by vaccination status, the difference in rates is not statistically significant.
This initial analysis did not control for specific comorbidities other than stratifying by age and vaccination status. Patients who were hospitalized within one day of their COVID-19 diagnoses were excluded because they might not have had time to initiate Paxlovid treatment to prevent hospitalization. Patients on other antiviral medications or who took Paxlovid in the 90 days prior to their relevant COVID diagnosis infection or six or more days after their COVID diagnosis were also excluded.
An individual’s likelihood of contracting COVID-19 and the severity of the individual’s illness is dependent on many factors including COVID-19 variant and whether the individual has had COVID-19 in the past. Additional analysis is planned to adjust for risk factors, such as underlying conditions and race/ethnicity, and will be made available on Epic Research when published. This further analysis is in collaboration with the CDC.
