According to the Centers for Disease Control and Prevention (CDC), the hospitalization rate for people in their 20s who tested positive for coronavirus was less than four percent between January and May. But a new study published in the Journal of Adolescent Health claims young people who smoke or vape are at significantly higher risk of severe consequences from COVID-19.
The study, conducted by researchers at the University of California—San Francisco (UCSF), was developed using data from the National Health Interview Survey (NHIS), which interviews 35,000 households. The UCSF study includes more than 8,000 people ages 18 to 25 and attempts to estimate the medical vulnerability of this population using the CDC’s guidance on possible risk factors for COVID-19.
The study concluded that 32 percent of this population, young adults, is vulnerable to severe COVID-19. But when the smokers and vapers were excluded from the analysis, the study estimated that the percentage dropped to 16 percent. “Recent evidence indicates that smoking is associated with a higher likelihood of COVID-19 disease progression, including increased illness severity, intensive care unit admission, or death,” said the study, which has already grabbed significant attention from major media outlets.
If you assume, without evidence, from the start that smoking or vaping are major risk factors, you should hardly be surprised that removing this group drives down the population’s risk. But the study’s biggest mistake is assuming that smoking or vaping increases the risk of severe COVID-19 in the first place. While these assumptions may be intuitive, they’re not supported by the data as it stands. The CDC itself has provided no evidence to suggest that smoking increases the risk of severe illness from COVID-19, and its own statistics tend to show that smokers are underrepresented in both the number of COVID-19 cases and hospitalizations.
This is the exact opposite of what we would expect if smoking was a significant risk factor. Since COVID-19 tends to attack the respiratory system, officials were worried that smokers could be a higher risk, but the data so far refute this concern. Some scientists have even hypothesized that nicotine may have a protective effect against COVID-19.
A living evidence review spearheaded by academics at University College London (UCL) found that in 12 ‘fair’ quality studies—a broad category where results are considered probably valid— smokers were less likely to test positive for COVID-19 than those who had never smoked. In seven other ‘fair’ quality studies, smokers were no more likely to be hospitalized as a result of COVID-19 than never smokers. The review also showed there was no significant difference in disease severity between smokers and nonsmokers. However, in five ‘fair’ quality studies, smokers were more likely to die in-hospitals of COVID-19 than those who had never smoked. Unfortunately, the UCSF study does not address or cite any of this research.
What’s even more jarring about the UCSF study is that vaping is classified as a smoking-related risk factor. Nowhere does the CDC list vaping as a possible risk factor for severe COVID-19. And there is currently no evidence from anywhere else in the world indicating vapers are at higher risk for COVID-19. Instead, UCSF researchers cite a study published in the British Medical Journal (BMJ) on the respiratory effects of e-cigarettes and an article by the head of the National Institute on Drug Abuse (NIDA).
The BMJ paper is far from instructive when it comes to the risks of e-cigarettes. It systematically ignores evidence contradicting the claim that vaping is safer than smoking and selectively reports negative conclusions without addressing their validity or critiques. Similarly, the NIDA article suggests vaping like smoking “may also harm lung health” but concedes it’s unknown whether vaping can lead to diseases like chronic obstructive pulmonary disease, COPD. The only evidence NIDA cites is a study showing influenza virus-infected mice exposed to e-cigarette vapor for four months.
The cottage industry of anti-vaping research has left some academics red-faced. Stanton Glantz, also of UCSF and an e-cigarette critic, had his study claiming vaping doubles the risk of heart attacks deemed unreliable and retracted last year. A separate study he co-authored earlier this year, claiming e-cigarettes are an independent risk factor for respiratory disease, is the subject of a working paper by economists at Cornell. Their replication of Glantz’s work found “no evidence that current or former e-cigarette use is associated with respiratory disease,” which might lead to another retraction.
Unfortunately, any study portraying tobacco or vaping in a negative light seems more often than not presumed to be true, no matter how weak or methodologically challenged. Conversely, any evidence suggesting the opposite is treated as suspect. In this case, there’s no actual evidence as of yet connecting vaping or smoking to increasing young peoples’ susceptibility to COVID-19.
A version of this column previously appeared on RealClearHealth.com.