Should you disinfect yourself with a hairdryer?

Absolutely not.

Attempting to do so can cause serious burns.

A video of a Florida County Commissioner, Bryant Culpepper, claiming that sticking a running a hairdryer directly into one’s face and inhaling the hot air will kill prevent COVID19 has been circulating on social media. In the video Culpepper states that the virus matures in nasal cavities before migrating to the lungs and causing COVID-19, and proposed killing the virus by running a hairdryer in ones face. Multiple outlets immediately criticized Culpepper for the statement.  Culpepper has since apologized for spreading misinformation, citing his original source as a Fox News program.  Indeed, others have asserted the claim publicly.

Here we pull apart the argument for blowing a hairdryer in your face to prevent COVID19. The early take-away message is: Please do not stick a hair dryer in your face, up your nose or mouth to fight coronavirus. You can burn yourself very badly, and you won’t kill the SARS-CoV-2 virus that causes COVID19 in the process.

False Assumption 1 – Nasal disinfection can somehow eliminate a virus

This claim emerges and re-emerges again and again in various forms of misinformation, such that the WHO has made infographics to dispel ideas that rinsing or spraying noses with saline or harsher chemicals , drinking alcohol or taking a hot bath will halt a SARS-CoV-2/COVID19 infection. Here is why “disinfection” of your mucous membranes doesn’t work.

All viruses need a host cell to complete their lifecycle. When a coronavirus enters a nasal passage, for example, it escapes the mucous barrier to enter cells lining the respiratory tract (airway epithelial cells). Once inside those cells it initiates its own replication, making new virus, using the host cell components. Those virions (new virus) are shot out of the cell through a process called exocytosis, which leaves the cell intact to just keep on completing viral replication (nice little summary here. In later posts we’ll post more on the molecular interactions involved in this process). Those virions infect more airway epithelial cells and so on. The virus SARS-CoV (agent of SARS), for example, progresses down the respiratory tract to infect other cell types as well as epithelial cells in the alveoli, and bronchi in a matter of days.

The point is, once a coronavirus is in a cell (and it gets in pretty fast), it’s in. You can’t disinfect or rinse it “out”.

False Assumption 2 – you can heat up your nasal passages to a temperature that can kill the novel coronavirus (SARS-CoV-2) without injuring yourself

Heat applied at 56ºC (or 132ºF) for 15 minutes kills the SARS coronavirus. Commercially available cosmetic hair dryers usually can maintain a heat output of about 60ºC (140ºF). Your own cells sustain significant damage at 40ºC-47ºC (104ºF-116.6ºF) and often undergo cell death in response temperatures above 50ºC (122ºF). Nevermind that drying out mucosal membranes can cause respiratory distress.

The short of it is 1) applying heat to your nasal passages doesn’t stop the virus from doing anything 2) you cannot apply a hairdryer blowing heat to your face without hurting yourself. Do not do it.

JGS and JFB March 31, 2020