New observational studies link early oral antiviral treatment to lower long COVID risk and better recovery after Omicron infection

A recent cohort study published this month found that early oral antiviral treatment in outpatients with COVID-19 was linked to a lower risk of developing long COVID and faster recovery after Omicron infection. According to the study and a CIDRAP summary, patients who received antivirals had a 14% reduced risk of post-COVID-19 condition compared to those who did not receive the treatment.

The study, published this month in a peer-reviewed journal and summarized by the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP), reported an adjusted risk ratio (aRR) of 0.86 for post-COVID-19 condition (PCC) among outpatients treated early with oral antivirals, indicating a 14% relative reduction in long COVID risk compared to untreated patients. The 95% confidence interval ranged from 0.78 to 0.93, supporting the statistical significance of the finding, according to the PubMed record titled “Early-Phase Oral Antiviral Use and Post-COVID-19 Condition in Outpatients.”

The CIDRAP summary further detailed that the estimated absolute risk of long COVID was 21.5% among antiviral recipients versus 25.1% in those who did not receive antivirals, yielding an adjusted risk difference of minus 4.14 percentage points.

This translated to a number needed to treat (NNT) of approximately 24.2, meaning that roughly 24 patients would require early antiviral therapy to prevent one case of long COVID under the study’s assumptions. The research focused on mildly ill, nonhospitalized patients infected during the Omicron era, emphasizing the outpatient setting.

The cohort study examined two specific oral antivirals: ensitrelvir and molnupiravir. Ensitrelvir recipients showed an aRR of 0.86 for PCC, with a 95% confidence interval from 0.79 to 0.95, while molnupiravir recipients had an aRR of 0.81, with a 95% confidence interval of 0.67 to 0.98. CIDRAP reported that among 1,698 patients treated with ensitrelvir, the NNT to prevent one long COVID case was 26.0, and among 385 molnupiravir recipients, the NNT was 17.9.

Beyond the reduced incidence of long COVID, the study also found that patients receiving early oral antivirals were less likely to report failure to return to usual health by day 84 after infection. The rates were 9.9% in the antiviral group compared to 12.9% among those not treated, with an adjusted risk ratio of 0.77 and a 95% confidence interval of 0.67 to 0.89, according to the PubMed abstract. This secondary outcome suggests that early antiviral treatment may facilitate faster recovery from COVID-19 symptoms.

The research was conducted during the Omicron variant wave and involved community-managed, nonhospitalized patients, making the findings most applicable to outpatient treatment initiated soon after diagnosis. However, the studies were observational and did not involve randomized controlled trials, so while the associations are statistically significant, they do not establish causality. The authors and CIDRAP noted that confounding factors and selection bias could influence the results, though consistent findings across different antiviral agents strengthen the observed association.

The broader context for these findings includes existing evidence that oral antivirals reduce acute severe outcomes of COVID-19. The U.S. Food and Drug Administration (FDA) authorized Paxlovid for mild-to-moderate COVID-19 in patients at high risk for progression to severe disease, recommending initiation within five days of symptom onset. FDA data cited an 88% reduction in COVID-19-related hospitalization or death in treated high-risk patients compared to placebo. Pfizer’s EPIC-HR trial interim analysis reported an 89% reduction in hospitalization or death when Paxlovid was administered within three days of symptom onset. This acute-phase efficacy provides a rationale for investigating whether early antiviral treatment also mitigates longer-term complications such as long COVID.

While the new cohort study and CIDRAP summary provide evidence linking early oral antiviral use to both a modest reduction in long COVID risk and improved recovery speed, the observational nature of the data means that further research, including randomized trials, will be needed to confirm these associations and clarify mechanisms. The findings contribute to a growing body of literature examining the potential benefits of early antiviral therapy beyond preventing severe acute illness.