A Centers for Disease Control and Prevention (CDC) epidemiologist provides insights on a large study.
It has been suggested that therapeutic use of nirmatrelvir/ritonavir (Paxlovid) for acute COVID-19 infection decreases the incidence of Post-COVID Conditions (PCC) or Long COVID. However, there is limited data on the subject, with most of it pertaining to specific age groups and populations.
A new, large observational study using healthcare data suggests it does reduce Long COVID in patients who are 50 years of age and above. However, among 2 younger cohorts, (younger adults and adolescents) there were mixed results.
“Among adults aged ≥ 50 years, the risks of overall and individual PCCs were generally lower among case- than control patients ([relative risk] RR for ≥1 condition=0.92, 95% CI=0.91-0.93),” the study investigators wrote. “There was no overall difference in risk among adults 18-49; the RR of individual conditions varied. Among adolescents, the risks of overall and individual PCCs were higher among case than control patients (RR for ≥1 condition=1.07, 95% CI=1.02-1.12).”
Alexandra F. Dalton, PhD, epidemiologist, CDC, presented findings on this study at IDWeek 2023.
“We saw in younger adults that there wasn't really much of a statistically meaningful relationship between Paxlovid use and overall PCC,” Dalton said. “And when we looked at individual conditions, we saw a few where it looked like there was a reduced risk and a few where there's an increased risk. And then among adolescents, there were just a handful of individual conditions where we saw increased risk."
Asked why the differences in the results in the various age groups, and Dalton says there are no conclusive findings.
“We're not entirely sure exactly what the reasons are, although we suspect it goes back to differences in baseline health between the age groups,” Dalton said.
They matched treated (300,000) and untreated patients (600,000) 1 to 2. They then compared the risk of 45 individual post COVID conditions, and 2 measures of overall PCC, explained Dalton.
“One measure was having at least 1 or more conditions, and then the second overall measure was having at least 2 or more PCC conditions,” Dalton said. “And we conducted our annual analysis separately by age groups: for adolescents ages 12 to 17; younger adults 18 to 49; and older adults, 50 and up.”
Dalton acknowledges there is still a lot to uncover and many questions to be answered.
“One of the things that our team is really interested in is looking at whether there's a difference in Paxlovid prescriptions by the number of underlying medical conditions that an individual has. So are people with more underlying conditions more likely to get a Paxlovid prescription? And how might that affect what we see in the analysis?”
Dalton A, Baca S, et al. Use of Paxlovid for Treatment of Acute COVID-19 and Occurrence of Post-COVID Conditions among Children and Adults at High-Risk for Severe COVID-19, April 1 - December 31, 2022. Presented at: IDWeek 2023. October 11-14, 2023; Boston, MA. Abstract 1937.