Do hairdryers get rid of the coronavirus?

Updated: Apr 20


TL;DR- NOT QUITE.


We’re being saturated with information regarding the evolving COVID-19 pandemic, and during uncertain times, it’s natural to seek out some type of clarity with whatever is in your own control. Recently, this phenomenon has begun presenting itself through headlines that claim to get rid of the novel coronavirus through unconventional methods. In recent news, a lawmaker local to Florida claimed to find the cure for Covid-19 by stating that aiming a hairdryer heated to 136°F into your nostrils, should kill the coronavirus. [1]

Sound sketch? We thought so too, so we did some digging.



Imagine wasting electricity to inflict third degree burns on yourself. Save some money on your utilities and unnecessary pain, seriously. The relationship between heat/light and its impact on the viability of the novel coronavirus (SARS-CoV-2) has been circulating the media with headlines such as:


We’re here to examine this fact or fad: Does heat (hairdryer delivered, or not) rid us of the novel coronavirus?

While a preliminary study has shown a negative correlation between average temperature and COVID-19 incidence for temperatures of 1°C and higher, there is no guarantee that the pandemic will subside with increasing temperatures with the coming spring and summer seasons because temperature only explained 44% of the variation in incidence of disease for this model—a relatively modest amount. [2] Though the seasonality of many human respiratory diseases has historically been recognized, temperature is only one part of the equation that may contribute to overall incidence. [3-5]



Since this is a relatively new outbreak and information regarding SARS-CoV-2 is being investigated in real time, keep in mind that SARS-CoV-1 which was identified in 2003 is the most closely related human coronavirus that could be used as a comparator. [9] A study conducted in 2011 on the viability of the SARS-CoV-1 strain showed that average temperatures and relative humidity that mimicked typical air-conditioned environments allowed for sustained viral viability for a period of 5 days. On the other hand, at higher temperatures and higher relative humidity, viral viability was rapidly lost which was thought to contribute to higher disease transmission rates in subtropical vs tropical regions.[6] Another study found that daily average temperature and daily average relative humidity were also inversely related with the secondary attack rate of SARS-CoV-1. Since secondary attack rate is the probability that an infection occurs among a certain group, it provides insight into how social interactions relate to transmission, and this study underscores the correlation between higher temperatures and lower disease incidence.[7]


In addition to its effect on viral viability, temperature and humidity also have an impact on our respiratory tract and subsequent innate immune responses. Inhalation of cold, dry air can cause damage to the nasal and tracheal mucosal surfaces and result in increased mucin production, impair mucociliary clearance to remove mucus and potentially harmful foreign substances from the lungs, and impact antiviral defense mechanisms. [4,8] Based on this and similarities between expression of immune receptors for SARS-CoV-1 and SARS-CoV-2, the authors of this study speculate that the impact on respiratory and immune cells in low humidity and temperature environments could promote the viability of the novel coronavirus and allow for rapid transmission between infected individuals in these conditions. [4]

Ultimately, it’s important to note that the situation is still currently unfolding and circumstances continue to evolve everyday. Accurate evidence will take time to be reviewed, evaluated and validated. But what we DO know is that viral characteristics, environmental effects AND human behavior all impact disease transmission. So, keep washing your hands for roughly 20 seconds with warm water and soap and socially distancing yourself for effective measures, which are, needless to say, safer than directing a hairdryer at your face.


Primary Author:

Monica Nguyen

B.S. Biochemistry & Cellular Biology | UC San Diego

MPH Candidate | Dartmouth College


Contributors:

Divya Chawla, Shruthi Patchava, Arushi Krishnan, Minda Liu

MPH Candidates | Dartmouth College


References

1. Local lawmaker says hair dryer can cure coronavirus. https://www.wpbf.com/article/local lawmaker-says-hair-dryer-can-cure-coronavirus/31906474. Accessed March 30, 2020. 2. Bannister-Tyrrell M, Meyer A, Faverjon C, Cameron A. Preliminary evidence that higher temperatures are associated with lower incidence of COVID-19, for cases reported globally up to 29th February 2020. medRxiv. March 2020:2020.03.18.20036731. doi:10.1101/2020.03.18.20036731 3. Dowell SF, Shang Ho M. Seasonality of infectious diseases and severe acute respiratory syndrome - What we don’t know can hurt us. Lancet Infect Dis. 2004;4(11):704-708. doi:10.1016/S1473-3099(04)01177-6 4. Moriyama M, Hugentobler WJ, Iwasaki A. Seasonality of Respiratory Viral Infections. Annu Rev Virol. 2020 March. doi: 10.1146/annurev-virology-012420-022445. [Epub ahead of print] 5. Yuan J, Yun H, Lan W, et al. A climatologic investigation of the SARS-CoV outbreak in Beijing, China. Am J Infect Control. 2006 May;34(4):234-6. DOI:10.1016/j.aijc.2005.12.006 6. Chan KH, Peiris JSM, Lam SY, Poon LLM, Yuen KY, Seto WH. The effects of temperature and relative humidity on the viability of the SARS coronavirus. Adv Virol. 2011. doi:10.1155/2011/734690 7. Cai QC, Lu J, Xu QF, et al. Influence of meteorological factors and air pollution on the outbreak of severe acute respiratory syndrome. Public Health. 2007 Apr;121(4):258-65. Doi:10.1016.j.puhe.2006.09.023 8.Sun Z, Thilakavathy K, Kumar SS, He G, Liu S V. Potential factors influencing repeated SARS outbreaks in China. Int J Environ Res Public Health. 2020. doi:10.3390/ijerph17051633 9.N van Doremalen N, Bushmaker T, Morris DH, et al. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. New England Journal of Medicine. 2020.


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