COVID, Paxlovid, & Senior Citizens

This is discouraging news. All I know is that Paxlovid worked like a miracle drug when my sister had COVID last year.

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From Medical Xpress 2/20/25:

Paxlovid's promise fades: Vaccinated seniors see minimal COVID-19 protection

"Paxlovid does not significantly reduce COVID-19 hospitalization and mortality among vaccinated older adults, according to new UCLA-led research.

"The study questions the assumption that Paxlovid's effectiveness in reducing COVID-19 hospitalizations and deaths in unvaccinated adults also applies to vaccinated adults. Pfizer's 2022 clinical trial found reduced COVID-19 hospitalization in unvaccinated middle-aged adults, while a subsequent 2024 clinical trial found no significant reduction in vaccinated middle-aged adults.

"The findings, published in JAMA, "are important because Pfizer's 2022 clinical trial continues to serve as the foundation of evidence supporting Paxlovid's perceived effectiveness, list price of about $1,650 per treatment course, and widespread global use," Mafi said.

"Since the study found no significant effect on COVID-19 hospitalizations and deaths among vaccinated older adults, our findings underscore the urgent need for further randomized-clinical trials investigating Paxlovid's effects in higher-risk populations, such as older subgroups who are frail or immunosuppressed," said Dr. Katherine Kahn, distinguished professor of medicine in the general internal medicine division and the study's senior author.

"To determine the association between Paxlovid and COVID-19-related hospitalizations, all-cause hospitalizations and all-cause mortality outcomes, the researchers exploited a natural experiment in Ontario, Canada.

"Between April 1 and November 30, 2022, Ontario implemented an age-restrictive policy on access to Paxlovid—reserving it for symptomatic, COVID-19-positive adults aged 70 years and older, unless they were immunocompromised or had other risk factors. The researchers used data from several Ontario health databases linked by ICES, the major steward of Ontario health data.

"They compared outcomes of patients who were just below vs. just above 70-years-old who were plausibly similar except for their exposure to Paxlovid. The researchers found that among 1.6 million highly vaccinated older Ontarians, the policy to restrict Paxlovid to those aged 70, increased the rate of Paxlovid prescriptions by 118% at age 70.

"This doubling in the prescription rate did not, however, translate into improved COVID-19-related hospitalization, all-cause hospitalization, or all-cause mortality outcomes.

"By restricting Paxlovid access by age, the policy created a rare natural experiment that the study analyzed to evaluate Paxlovid's impact on key health outcomes, effectively avoiding the common observational research pitfall known as unobserved confounding.

"Unobserved confounding is a problem because the decision to use Paxlovid is not random, and the factors that influence its use are able to influence the risk of hospitalization or mortality," said study co-author Sitaram Vangala, biostatistician in the Department of Medicine Statistics Core.

"Because access to Paxlovid in this study was in effect randomized for those close to the age 70 cutoff, our results are unlikely to reflect unobserved confounding," Vangala said.

"This may explain why our results align with the recent negative 2024 clinical trial among vaccinated middle-aged adults, but not with observational studies showing that Paxlovid is associated with large reductions in hospitalization and mortality in vaccinated older adults."

"The study is limited by a lack of individual patient-level data regarding symptoms, timing of previous COVID-19 vaccinations, receipt of Paxlovid, and medication adherence."

Additional co-authors Manying Cui and Artem Romanov of UCLA, and Dr. Moira Kapral and Dr. Peter Wu of the University of Toronto. Dr. Wu is affiliated with ICES