PAXLOVID safety under the microscope: 3,300 patients studied

NCT ID NCT05263908

Completed Knowledge-focused Sponsor: Pfizer Source: ClinicalTrials.gov ↗

First seen Jun 26, 2026 · Last updated Jun 26, 2026

Summary

This completed study from Pfizer looked at the safety and effects of the COVID-19 medicine PAXLOVID in over 3,300 people aged 12 and older. All participants took PAXLOVID twice a day for five days and were monitored for 28 days. The main goal was to track any side effects, including serious ones. Because this was an observational study, it helps us understand how the drug works in everyday use, but it does not compare PAXLOVID to a placebo or other treatment.

What this could mean

Our plain-language read of the trial. This is informational only — not medical advice or a prediction.

Active substance: nirmatrelvir / ritonavir (PAXLOVID)
What this could lead to: If successful, this study could confirm that PAXLOVID is safe and effective for treating COVID-19 in a real-world setting.
What could go wrong: This is an observational study, not a controlled trial, so results may be less reliable. It also only looks at short-term safety over 28 days.

This is an AI summary of the original study and may miss details. Read our disclaimer.

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Conditions

The condition(s) this trial relates to.

COVID-19

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

SARS-COV-2 INFECTION

Contacts and locations

Locations

Pfizer Local County

Tokyo, 1518589, Japan

More trials for these conditions

Other studies related to the condition(s) this trial covers.