RESEARCHERS have reported that despite a doubling of prescriptions for COVID antiviral Paxlovid (nirmatrelvir-ritonavir) in Canada in 2022, there was no corresponding decrease in hospitalisations or death rates among highly vaccinated olderadults.
Paxlovid has been shown in trials to reduce COVID-related hospitalisations among middle-aged unvaccinated patients, but not vaccinated middle-aged adults.
The study authors said the effects on older and highly vaccinated populations were not known.
The UCLA-led research team exploited a natural experiment in Ontario, Canada, where an age-restrictive policy on access to Paxlovid was implemented.
They compared outcomes of patients who were just below vs just above 70 years old (the age at which Paxlovid could be prescribed) and who were plausibly similar except for their exposure toPaxlovid.
They found no significant drop in hospitalisations, even though the rate of prescriptions of Paxlovid more than doubled.
The researchers calculated that the drug may reduce COVID-related hospitalisations by 1.3 percentage points, which is four times smaller than the benefit reported in the original trial in unvaccinated adults (5.5 percentage points absolute riskreduction).
It was an observational study, and limitations included a lack of individual patient-level data, such as symptoms, medication adherence and timing of receipt of COVID vaccinations and Paxlovid.
"Since the study found no significant effect on COVID hospitalisations and deaths among vaccinated older adults, our findings underscore the urgent need for further randomised-clinical trials investigating Paxlovid's effects in higher-risk populations, such as older subgroups who are frail or immunosuppressed," said senior author Dr Katherine Kahn.
The full paper is HERE. KB
The above article was sent to subscribers in Pharmacy Daily's issue from 21 Feb 25
To see the full newsletter, see the embedded issue below or CLICK HERE to download Pharmacy Daily from 21 Feb 25
