The study confirms the usefulness of Paxlovid as an early-stage treatment for the prevention of COVID-19 in the hospital setting

A Kaiser Permanente study confirms the benefit of nirmatrelvir-ritonavir, also known as Paxlovid, as an early-stage treatment to prevent hospitalization for people with mild to moderate COVID-19, regardless of previous immunity or age. The study was published March 15, 2023, in The Lancet ID.

Among Kaiser Permanente members in Southern California who tested positive for coronavirus, receiving Paxlovid within 5 days of the onset of COVID-19 symptoms was associated with significant reductions in the risk of hospitalization or death. These results are all the more remarkable because in this population with high levels of vaccination, we continue to see additional benefits of this treatment.”

Sarah Tartouf, PhD, lead author of the study and an epidemiologist with the Division of Research and Evaluation at Kaiser Permanente Southern California

Paxlovid is an oral therapeutic drug intended to reduce the risk of severe outcomes of coronavirus infection. It is manufactured by Pfizer Inc. It is currently authorized for emergency use by the FDA for adults and children 12 years of age and older who are at high risk of progression to severe COVID-19.

Study analyzes included patients who obtained positive results from coronavirus tests conducted in outpatient settings between April 8 and October 7, 2022. In the study population, 7,274 subjects received paxlovid, and 126,152 subjects did not receive paxlovid. It was a time dominated by the omicron sub-variants BA.2, BA.4 and BA.5. Overall, 86% of the 133,426 participants received 2 doses of the COVID-19 vaccine, and 61% received 3 or more doses.

The study found:

• The efficacy in preventing hospitalization or death within 30 days after the positive test was 80% for subjects who were dispensed baxlovid within 5 days after the onset of symptoms.
  • Within the subgroup of patients who were dispensed baxlovid on the day of a positive COVID-19 test, the efficacy was 90%.
  • Efficacy decreased to 44% for patients who received Paxlovid 6 or more days after the onset of symptoms or in those without severe clinical symptoms.
  • Overall, for patients who received Paxlovid at any time within their clinical course, the efficacy was 54%.

• Efficacy in preventing ICU admission, mechanical ventilation, or death within 60 days after a positive COVID-19 test was 89% for patients who were dispensed Paxlovid 0 to 5 days after symptom onset, and 84% for people who were dispensed Paxlovid treatment at anytime.

“Our data showed that the sooner people take Paxlovid when symptoms appear, the more effective the drug will be,” Tartoff said. “However, there is still some benefit to treatment 6 or more days after the onset of symptoms. People should talk to their doctors about the best approach for them.”