On August 11, researchers from Stanford University published the results of an online survey about youth tobacco use and self-reported COVID-19 symptoms and tests. Open online surveys with anonymous participants are inherently unreliable, especially on topics as controversial as youth vaping that can attract “cheaters” hoping to influence the results. Nonetheless, surveys of this type can still provide some insight, but only if the study authors are honest about these limitations That does not seem to be what happened, in this case. As Stanford’s press release noted and numerous media outlets repeated (apparently without reading the study), participants who said they ever used e-cigarettes were five times more likely to report testing positive for COVID-19, and those who reported both ever vaping and ever smoking were seven times more likely test positive than those who said they never used tobacco. But their conclusions make little sense based on what they reported.
First off, the study reports finding an association between “ever” use but no association with recent e-cigarette use and testing positive for COVID-19. Why would, say, taking a hit off a friend’s Juul a year ago put people at greater risk of contracting the virus than would, say, daily e-cigarette use? The authors offer no real answer for this implausible finding. Assuming the results aren’t completely bogus, one plausible explanation could be that people inclined to experiment with tobacco products are more inclined toward risk-taking in general—they may be less likely to adhere to social distancing and more likely to engage in behaviors that increase risk of contracting COVID-19.
Furthermore, the authors did not adjust the results based on testing rates. That is, if one group was tested much more than another, you’d expect the group with more testing to have more confirmed cases. And that’s exactly the scenario reported by this study: 17.5 percent of the participants who said they had ever used e-cigarettes reported receiving a COVID-19 test, compared to only 5.7 percent of non-tobacco users.
Calculating risk based on only those who received COVID-19 tests, e-cigarette users were actually slightly less likely than never users to test positive. In fact, based on the study’s results, recent users of either cigarettes or e-cigarettes were far less likely to report testing positive for the illness than those who reported using them in the distant past, leading to the counterintuitive conclusion that if someone uses a tobacco product they would be better off (at least with regard to COVID) by continuing to smoke or vape rather than quit.* And these are just some of the many issues experts in and outside of the tobacco research field have raised about the study.
On top of paradoxical results and dubious methods, there are questions about the authors’ conflicts of interest. In particular, Bonnie Halpern-Felsher, the study’s senior researcher, is a self-described anti-vaping advocate. She is one of the founding advisory board members for the anti-vaping pressure group, Parents Against Vaping E-cigarettes (PAVe), and the study she authored was funded in part by an NIH grant assigned to Stanton Glantz, one of the most prominent and outspoken opponents of safer nicotine. Then there’s the fact that Halpern-Felsher is a member of the editorial board at the journal that published the study. The study got through the peer-review process and to publication in just under three weeks.
None of these limitations, questions, or glaring problems stopped those e-cigarette opponents from latching onto the study and citing it as a basis for immediate federal action. Within hours of publication, Rep. Raja Krishnamoorthi (D-IL) sent a letter to FDA Commissioner Stephen Hahn asking him to “clear the market of all e-cigarettes” because of the supposed increased COVID-19 risk. About a week later, nine Senate Democrats sent a similar letter to Health and Human Services Secretary Alex Azar, urging his agency to clear the market of all non-tobacco flavored e-cigarettes.
But a single study—even one of the highest quality and reliability—is insufficient evidence on which to base public policy. As e-cigarette opponents are usually quick to note, individual studies must be viewed in the broader context of the research literature on a topic. At least, this is the sort of argument e-cigarette opponents make in response to studies that show the relative safety and effectiveness of e-cigarettes.
*This result actually falls in line with the hundreds of studies, conducted around the world, that have found smokers are significantly underrepresented in COVID-19 positive populations, a finding that has led some to launch clinical trials testing the potential role of nicotine to offer some protection against the illness.