key: cord-356164-y778k3hs authors: Komiyama, Maki; Hasegawa, Koji title: Smoking Cessation as a Public Health Measure to Limit the Coronavirus Disease 2019 Pandemic date: 2020-04-23 journal: Eur Cardiol DOI: 10.15420/ecr.2020.11 sha: doc_id: 356164 cord_uid: y778k3hs The novel coronavirus disease 2019 (COVID-19) has already evolved into a rapidly expanding pandemic. Risk factors for COVID-19, such as cardiovascular disease, chronic obstructive pulmonary disease and diabetes, are all strongly associated with smoking habits. The effects of cigarette smoking on the transmission of the virus and worsening of COVID-19 have been less addressed. Emerging data indicate that smoking history is the major determinant of worsening COVID-19 outcomes. Smoking cessation recovers airway ciliary clearance and immune function. Thus, smoking cessation awareness is strongly encouraged as a public health measure to limit the global impact of COVID-19. In a report on 1,099 infected individuals from China, 12.4% of current smokers and 23.8% of past smokers developed critical outcomes, including being admitted into an intensive care unit or fitted with a ventilator, or mortality. In comparison, only 4.7% of those who had never smoked developed critical outcomes. 11 Additionally, the proportion of patients with severe symptoms was 21.2% among current smokers and 42.9% among past smokers, which was higher compared with those who had never smoked (14.5%). 11 In this report, the analysis was just a simple comparison. Usually, past smokers were older than current smokers. Therefore, a high age in past smokers may contribute to their worsening outcomes. A small study from China using multivariate analysis identified the following four factors as being associated with COVID-19 deterioration: smoking history, body temperature of >37.3°C at the time of admission, respiratory failure and age ≥60 years. 12 Among these, the OR for smoking history was highest at 14 (CI [1.6-45]; p=0.018), which was higher than the ORs for other factors associated with disease deterioration (8.5-9.0). As noted earlier, COVID-19 is considered to be severe and associated with a higher mortality rate in elderly patients with underlying diseases; it is worth noting that underlying diseases related to the severity of COVID-19, such as cardiovascular disease, chronic obstructive pulmonary disease and diabetes, are all strongly associated with smoking. 13, 14 COVID-19 is primarily a disease of the respiratory tract, and virus entry into cells, viral replication and virion release occur within the respiratory tract. 15 Angiotensin-converting enzyme (ACE) 2 converts the vasoconstrictor angiotensin II to vasoprotective angiotensin. [1] [2] [3] [4] [5] [6] [7] Multiple studies have shown that ACE-2 is a host receptor for SARS-CoV-2. 16 SARS-CoV-2 enters cells through ACE-2 receptors present in mucosal epithelial cells and alveolar tissues in a clathrin-dependent process. Cigarette smoking increases the expression of ACE-2 in pulmonary tissues, which could in part account for the increased risk of infection. 17, 18 Additionally, the WHO has noted that smokers perform repeated hand to face reciprocal movements, which contribute to increased opportunity for virus entry. 19 ACE inhibitors and angiotensin-receptor blockers also increase the expression of ACE-2 receptors, which could increase the risk of COVID-19 infection. In fact, the ECDC reported that 74% of COVID-19 fatalities in Italy had concomitant hypertension, suggesting an association with these drugs. 10 Many societies, including the European Society of Cardiology, have issued alerts that patients with cardiovascular diseases discontinue ACE inhibitors and angiotensinreceptor blockers. 20 Switching to calcium antagonists has been suggested; however, further evidence for this is needed. 21 Although only a few reports on smoking have been published to date and further accrual of evidence is warranted, smoking is likely to be an important and significant factor associated with COVID-19 severity. Cigarette smoking decreases lung function, and evidently poses a general risk factor for severe respiratory infections, thus there is an apparent association between cigarette smoking and COVID-19 severity. The detailed mechanism by which COVID-19 becomes more severe in patients with a history of cigarette smoking warrants further investigation. There is also a need for more evidence on the effect of second-hand smoke on the spread of SARS-CoV-2. However, according to published COVID-19 research reports, even at this stage, it might be well assumed that smokers are likely to be at serious risk for contracting SARS-CoV-2 infection. Smoking cessation recovers airway ciliary clearance and immune function as early as 1 month. Thus, smoking cessation awareness is strongly encouraged as part of public health measures to limit the global impact of COVID-19. WHO. Coronavirus disease (COVID-19) outbreak. Geneva: WHO, 2020 Cigarette smoke alters respiratory syncytial virus-induced apoptosis and replication Cigarette smoking and infection MERS transmission and risk factors: a systematic review Suppression of human IL-1β, IL-2, IFN-γ, and TNF-α production by cigarette smoke extracts Evidence for the immunosuppressive role of nicotine on human dendritic cell functions Nicotine impairs the response on lung epithelial cells to IL-22 Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19) WHO. WHO report on the global tobacco epidemic 2019. WHO: Geneva, 2020 European Centrr for Disease Prevention and Control. Coronavirus disease 2019 (COVID-19) pandemic: increased transmission in the EU/EEA and the UK -seventh update. ECDC: Stockholm Clinical characteristics of coronavirus disease 2019 in China Analysis of factors associated with disease outcomes in hospitalized patients with 2019 novel coronavirus disease Eleven faces of coronavirus disease 2019 Medical management and prevention instruction of chronic obstructive pulmonary disease during the coronavirus disease 2019 epidemic. Zhonghua Jie He He Hu Xi Za Zhi SARS-CoV-2 viral load in upper respiratory specimens of infected patients A pneumonia outbreak associated with a new coronavirus of probable bat origin Cancer patients in SARS-CoV-2 infection: a nationwide analysis in China Risk of COVID-19 for cancer patients WHO. Q&A on smoking and COVID-19. WHO: Geneva, 2020 Position statement of the ESC Council on Hypertension on ACE-inhibitors and angiotensin receptor blockers Are patients with hypertension and diabetes mellitus at increased risk for COVID-19 infection?