Study found Pfizer’s Paxlovid only helped over 65s avoid hospitalisation and death

Pfizer’s Paxlovid (nirmatrelvir and ritonavir tablets) significantly lowered the rates of hospitalisation and death among patients 65 years or older, but showed no evidence of significant benefit in younger adults, a new observational study published in the New England Journal of Medicine found.

Paxlovid is an orally administered drug that should be given at the first sign of infection for the treatment of patients with mild-to-moderate COVID-19 in adults and paediatric patients – 12 years and older weighing at least 40kg – who are at high risk for progression to severe COVID-19.

The treatment has not been approved, but has been authorised for emergency use by US Food and Drug Administration (FDA) under an Emergency Use Authorisation (EUA) in December 2021. It has also been approved for emergency use in more than 65 countries.

In the Israel-based study, researchers studied data from 109,000 patients at Clalit Health Service – nearly all of whom had been vaccinated against COVID-19, been previously infected, or both – and tracked their hospitalisation and death rates by age.

The study looked at just under 43,000 patients who were 65 years or older, and found hospitalisation due to COVID-19 occurred in 11 patients treated with Paxlovid (14.7 cases per 100,000 person-days) and in 766 untreated patients (58.9 cases per 100,000 person-days).

Meanwhile, among the more than 66,000 patients who were 40 to 64 years old, hospitalisation occurred in seven treated patients – 15.2 cases per 100,000 person-days – and in 327 untreated patients – 15.8 cases per 100,000 person-days – demonstrating no statistically significant drop.

A similar result was observed in terms of Paxlovid reducing COVID-19 related deaths, among patients aged 40 to 64 years old, as death due to COVID-19 occurred in one treated patient and in 16 of untreated patients. This is compared to the significant difference observed in the 65 years and older group, with death due to COVID-19 occurring in two treated patients and in 158 of untreated patients.

Across both age groups, a lack of previous SARS-CoV-2 immunity and a previous hospitalisation were the variables that were most strongly associated with high rates of hospitalisation due to COVID-19, the study noted.

The results follow a recent letter from the FDA, which ordered Pfizer to test the effects of an additional course of Paxlovid among individuals who experience a rebound in COVID-19 after the first course of treatment, following reports of rebounding COVID-19 symptoms after the first course of treatment.