Pfizer’s flailing blockbuster Paxlovid seemed like a promising option for patients with long COVID. Now, that hope has been once again dashed.
After a 15-day course of Paxlovid in 155 patients, researchers from Stanford Medicine reported this month that the drug was no more effective than a placebo at reducing long COVID’s six “core” symptoms.
In theory, the antiviral should be a good candidate for treating the condition’s constellation of woes that can include brain fog, shortness of breath, body aches, fatigue, gastrointestinal distress and more. In acute COVID-19, Paxlovid’s antiviral punch has been shown to slash the likelihood of hospitalization and death by 89% in high-risk adults.
And although researchers have yet to pin down the exact reason some people infected with COVID-19 develop symptoms that last for months or years, evidence has pointed to persistent antiviral replication or molecular debris from the virus as potential culprits, which would lend itself to an effective antiviral approach.
But studies have shown otherwise, and the latest trial follows other disappointing results from researchers attempting to thwart long COVID with Paxlovid. One study published earlier this year found that the antiviral failed to prevent long COVID in vaccinated patients experiencing their first bout of the illness.
Deepening insight into long COVID’s impact
As these studies come up short in the clinic, other researchers have built mounting evidence on long COVID’s deep toll.
About 7% of U.S. adults have grappled with the condition, according to a report released this month from the National Academies of Sciences, Engineering and Medicine, a group of nonprofits that provides policy advice and guidance.
The report noted that long COVID has now been linked to over 200 symptoms impacting “nearly every organ system.” Although patients with a severe bout of the infection are more likely to develop long COVID, it can also be triggered by mild cases.
With no FDA-approved treatments on the market for long COVID, the report noted patients are left with therapies targeting specific symptoms, which generally “improve over time.” But even though 18% to 22% of patients with symptoms at the six-month mark recovered after a year, the condition worsens for many others and often mirrors chronic and complex multisystem illnesses such as fibromyalgia.
The data supports recent findings by the Medical Expenditure Panel Survey Household Component that also estimated 7% of Americans have had long COVID. The survey indicated women are more commonly affected than men (8.5% of all females surveyed compared to 5.1% of males), and that it was more prevalent among white and Hispanic Americans.
The rates of long COVID were similar among Americans who’d been vaccinated (8.4%) and those who hadn’t (8.7%), but were markedly lower in those who’d gotten a booster (5.8%). Adults with chronic bronchitis, emphysema, asthma and obesity were more likely to report dealing with long COVID.
While researchers zero in on the prevalence of long COVID, the quest to find an effective therapy could be a long way from paying off.
There are fewer than 20 late-stage studies listed on clinicaltrials.gov assessing various treatments for long COVID. In addition to other studies for Paxlovid, researchers are trialing the SSRI Luvox, aspirin and an FDA-approved heart failure drug called ivabradine.
The NIH also announced in March it’s launching two phase 2 trials for certain long COVID symptoms that will involve ivabradine and a form of intravenous immunoglobulin called Gamunex-C alongside non-drug approaches such as a high-salt diet.
