Paxlovid Significantly Reduces the Risk of COVID-19 Hospitalization and Death

On March 16, the US Food and Drug Administration (FDA) Antimicrobial Drugs Advisory Committee (AMDAC) voted in favor of approving a New Drug Application (NDA) for Paxlovid.

Paxlovid, Pfizer’s orally administered combination of nirmatrelvir and ritonavir tablets, has been one of the most utilized therapeutic drugs to prevent severe outcomes of COVID-19 infection.

All but 1 of AMDAC’s members voted “YES” to the following question:

Is the overall benefit-risk assessment favorable for Paxlovid when used for the treatment of mild-to-moderate COVID-19 in adults who are at high risk for progression to severe COVID-19, including hospitalization or death?

Now, a new study, published in The Lancet Infectious Diseases, seems to concur with AMDAC’s finding that Paxlovid reduces the risk of COVID-19 hospitalization and death.

The matched observational outpatient cohort study was conducted in the Kaiser Permanente Southern California health care system. The investigators extracted data from electronic health records of nonhospitalized patients aged 12 years and older who tested positive for COVID-19 between April 8-October 7, 2022.

The primary study endpoint was estimated efficacy of Paxlovid (nirmatrelvir–ritonavir) in preventing hospital admission or death within 30 days of COVID-19 diagnosis.

Patient outcomes were compared between those who received Paxlovid and those who did not. The cohorts were matched by infection date, age, sex, BMI, vaccination history, comorbidities, health care seeking during the year prior, and clinical status (including care received, the presence or absence of acute COVID-19 symptoms at testing, and time from symptom onset to testing).

The final analyses included 7274 Paxlovid recipients and 126152 nonrecipients. Of all these COVID-19 patients, 75.2% of Paxlovid patients (n = 5472) and 67.1% of nonrecipients (n = 84657) were tested and diagnosed within 5 days of symptom onset.

The investigators found that Paxlovid had an estimated effectiveness of 53.6% in preventing hospital admission or death within 30 days of COVID-19 diagnosis. When Paxlovid was administered within 5 days of symptom onset, this efficacy increased to 79.6%. Efficacy increased to 89.6% when the subgroup of patients diagnosed within 5 days began Paxlovid on the day they tested positive.

“Overall, our findings suggest that early receipt of nirmatrelvir–ritonavir (ie, within 5 days of symptom onset) reduces risk of hospital admission or death in people testing positive for SARS-CoV-2 in outpatient settings, underscoring the continued need for prompt testing and treatment among people at high risk of progression to severe COVID-19,” the study authors concluded.