DayQuil, Covid Vaccine Boosters and FDA Science The industry studies that showed a decongestant was effective turned out to be flawed. Sound familiar? By Allysia Finley
If DayQuil never seemed to unstuff your nose, now you know why: Its core decongesting ingredient, phenylephrine, doesn’t work.
That’s what a Food and Drug Administration advisory committee unanimously concluded last week, 16 years after researchers first told the agency that evidence from the 1960s and ’70s purportedly demonstrating the ingredient’s efficacy was flawed. For decades, people have been taking what amounts to a placebo.
But unlike a sugar pill, phenylephrine can cause lightheadedness, queasiness, headaches and a rapid heartbeat. What took the FDA so long to act?
Perhaps typical bureaucratic inertia and reluctance to backtrack on “settled science.” This episode mirrors the debate over Covid boosters, which the FDA approved last week, the day before its advisory committee concluded phenylephrine is ineffective. As was the case for phenylephrine, booster recommendations are based on flawed studies and extrapolations.
The FDA concluded in 1994 that phenylephrine was “generally recognized as safe and effective” when administered orally, such as in a cold syrup, “even though the efficacy data were borderline,” according to an agency staff report. Why? Because the ingredient had proved effective when administered intranasally.
Yet studies as early as the 1930s showed that significantly higher doses of phenylephrine than are safe would be needed to have a decongesting effect, since it is mostly metabolized before reaching the bloodstream. At the time, however, the FDA credited positive evidence from poorly constructed industry studies.
When the agency revisited the issue in 2007, an industry meta-analysis of prior flawed studies showed phenylephrine was effective. But as an agency scientific adviser quipped at a regulatory briefing that March, “all meta-analysis is post facto. You only do it if you know you’re going to win.” The FDA then sought more studies to measure the efficacy of higher doses—yet the three placebo-controlled trials between 2015 and 2018 were negative.
In its recent review, FDA staff concluded that early studies demonstrating the drug’s efficacy were flawed and possibly biased. Ten, all from the same industry sponsor, had “multiple methodological and statistical issues” and apparent “data integrity” problems. Two “produced near textbook perfect results that could not be duplicated in other similarly designed studies.”
Why didn’t the FDA acknowledge this sooner? Perhaps because, as the agency’s review notes, doing so could lead consumers to switch to other medications that carry their own risks. Pseudoephedrine, the only other approved oral decongestant, must be bought “behind the counter” because it can be used to make methamphetamine.
“Some consumers may believe that [oral phenylephrine] is helpful to them, resulting in frustration and anger if it is no longer available to purchase,” the FDA added. But who wants to spend money on a dud drug? The review also cited “significant retooling costs to industry” if manufacturers have to reformulate products.
An admission of error might also lead the public to question the agency’s expert judgment. This is doubtless the concern that has animated the FDA’s ferocious pushback to questions about the benefits and necessity of Covid booster shots for everyone as young as 6 months.
“Public health experts are in broad agreement about these facts, and efforts to undercut vaccine uptake are unfounded and dangerous,” FDA Commissioner Robert Califf tweeted Friday.
The FDA last week approved updated boosters based on data showing they generated antibodies and past studies purportedly demonstrating that the original vaccine and earlier booster versions worked. But these are large extrapolations based on flimsy evidence. No placebo-controlled trials have shown the boosters are effective, and studies on prior boosters systemically suffer from what scientists call “healthy user bias”—the process by which healthier people, who are more likely to receive a treatment, skew retrospective analyses.
One widely cited study from Israel found people who got the first boosters were 90% less likely to die of Covid within a 54-day period. Yet scientists from Stanford and the University of California, San Francisco, who analyzed the data estimated that those who didn’t get boosters were also 94.8% more likely to die of non-Covid causes during the same period.
Criticism of the FDA’s rush to roll out boosters for everyone, regardless of risk, isn’t coming only from partisans. One of the most vocal critics has been UCSF epidemiologist Vinay Prasad, an avowed Bernie Sanders supporter, who has also ridiculed shaky evidence used to support mask mandates and lockdowns.
“The standard for truth and misinformation must be consistent,” Dr. Prasad wrote in a recent Substack post. “It is concerning when news outlets permit political scientists to lie to promote a dubious vaccination campaign that is not followed by peer nations.” The U.K. and Australia haven’t recommended boosters for healthy people under 65.
University of Pennsylvania professor Paul Offit, a leading vaccine advocate, has also criticized the weak evidence public-health officials have used to support updated boosters, especially for those at low risk. Officials have adopted a position of “absolutism,” he recently explained on a University of Iowa podcast, because “when you show that you’re in any sense questioning, it looks bad.”
Never mind that questioning the “science” is how science works.
At least the FDA is finally correcting the record on phenylephrine, but how many bottles of DayQuil did Americans needlessly consume before it did?
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