Nirmatrelvir-Ritonavir Treatment and Post-COVID-19 Conditions in Adolescents and Adults

Overview

This retrospective cohort study analyzed real-world claims data to evaluate whether nirmatrelvir-ritonavir treatment during acute COVID-19 reduces the risk of post-COVID-19 conditions (PCC) across different age groups. Results showed a significant reduction in PCC risk among adults aged 50 years and older, but minimal to no effect in younger adults and adolescents.

Background

Post-COVID-19 Conditions (PCC), or Long COVID, involve persistent symptoms or new conditions occurring weeks to months after acute SARS-CoV-2 infection, affecting multiple organ systems. Nirmatrelvir-ritonavir (Paxlovid™) is an antiviral authorized for treating mild-to-moderate COVID-19 in patients aged 12 and older at high risk of severe disease. While it reduces hospitalization and death, its impact on PCC risk remains unclear. This study aimed to clarify the association between nirmatrelvir-ritonavir treatment and PCC incidence across authorized age groups using a large US healthcare claims database.

Data Highlights

Key Findings

• Nirmatrelvir-ritonavir treatment within ±5 days of COVID-19 diagnosis was associated with a statistically significant reduction in PCC risk among adults aged 50–64 years (aHR 0.93) and ≥65 years (aHR 0.88).
• No significant reduction in PCC risk was observed in high-risk adolescents aged 12–17 years (aHR 1.06), indicating no protective effect in this group.
• High-risk adults aged 18–49 years showed only a minimal reduction in PCC risk (aHR 0.98) after treatment.
• The study utilized a broad definition of PCC, including 45 new-onset symptoms or conditions recorded ≥60 days post-COVID-19 diagnosis, enhancing sensitivity to detect Long COVID.
• Patients were matched 1:2 on age, sex, month of index date, and geographic region to control for confounding factors.
• Exclusions included patients hospitalized at index, pregnant individuals, and those with contraindications to nirmatrelvir-ritonavir, ensuring a focused outpatient population at higher risk for severe COVID-19.

Clinical Implications

Clinicians should consider prescribing nirmatrelvir-ritonavir for outpatient treatment of mild to moderate COVID-19 in adults aged 50 years and older to reduce both the risk of severe disease and subsequent development of PCC. The minimal to absent effect in younger populations suggests that benefits for PCC prevention may be limited to older adults. These findings support targeted antiviral use in higher-risk populations to mitigate long-term COVID-19 sequelae.

Conclusion

Nirmatrelvir-ritonavir treatment during acute COVID-19 is associated with a reduced risk of post-COVID-19 conditions in older adults but not in adolescents or younger adults. This real-world evidence supports antiviral use to prevent Long COVID primarily in older high-risk populations.

References

1. CDC/HealthVerity/2023 -- Evaluating Nirmatrelvir-Ritonavir and Post-COVID-19 Conditions