Evaluation of risk factors associated with SARS-CoV-2 transmission

Abstract

Objective

Coronavirus disease 2019 (COVID-19) has caused high morbidity and mortality worldwide. Since there is not enough evidence of risk factors of SARS-CoV-2 transmission, this study aimed to evaluate them.

Methods

This survey-based study was conducted across 66 countries from May to November 2020 among suspected and confirmed individuals with COVID-19. The stepwise AIC method was utilized to determine the optimal multivariable logistic regression to explore predictive factors of SARS-CoV-2 transmission.

Results

Among 2372 respondents who participated in the study, there were 1172 valid responses. The profession of non-healthcare-worker (OR: 1.77, 95%CI: 1.04–3.00, p = .032), history of SARS-CoV or MERS-CoV infection (OR: 4.78, 95%CI: 2.34–9.63, p < .001), higher frequency of contact with colleagues (OR: 1.17, 95%CI: 1.01–1.37, p = .041), and habit of hugging when greeting (OR: 1.25, 95%CI: 1.00–1.56, p = .049) were associated with an increased risk of contracting COVID-19. Current smokers had a lower likelihood of having COVID-19 compared to former smokers (OR: 5.41, 95%CI: 1.93–17.49, p = .002) or non-smokers (OR: 3.69, 95%CI: 1.48–11.11, p = .01).

Conclusions

Our study suggests several risk factors for SARS-CoV-2 transmission including the profession of non-healthcare workers, history of other coronavirus infections, frequent close contact with colleagues, the habit of hugging when greeting, and smoking status.

PLAIN LANGUAGE SUMMARY

Since there is not enough evidence of risk factors of SARS-CoV-2 transmission, this study aimed to evaluate them. The risk of SARS-CoV-2 infection was higher among non-healthcare workers and among those who had a history of being tested positive for SARS-CoV or MERS-CoV before the COVID-19 outbreak. The habit of frequent contact with colleagues or hugging when greeting significantly increased the risk of being infected with SARS-CoV-2. The current smokers had a lower risk of getting infected with SARS-CoV-2 than others who had a habit of smoking tobacco in the past or who had never smoked.

Keywords:

• COVID-19
• global survey
• health surveys
• risk factors
• transmission

Transparency

Declaration of funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of financial/other relationships

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

NTH, MNL, STMA, NTMD, and LVT conceived the study and designed the study protocol. MNL, STMA, NTMD, and LVT performed the data curation, software, formal analysis, validation, and drafted the manuscript. AQ, VU, RT, ICNR, LHNM, RR, SPD, HTNG, DP, FYA, BTDT, SK, PB, JS, JMAA, and the TMGH COVID-19 Collaborators carried out the data investigation and critically revised the manuscript for intellectual content. All authors read and approved the final manuscript. NTH supervised the study project.

Acknowledgements

None.

Data availability statement

The data used to support the findings of this study are available from the corresponding author upon request.

Ethics statement

The study obtained academic and ethical approval from the Institutional Review Board Office of the School of Tropical Medicine and Global Health, Nagasaki University, Japan (Reference number: NU_TMGH_2020_118_1).