World Health Organization. (2018). Global adult tobacco survey (GATS): Factsheet China 2018. https://www.who.int/docs/default-source/wpro---documents/countries/china/2018-gats-china-factsheet-cnen.pdf

Cai, H. (2020). Sex difference and smoking predisposition in patients with COVID-19. The Lancet Respiratory Medicine, 8(4), e2. https://doi.org/10.1016/S2213-2600(20)30117-X

National Center for Immunization and Respiratory Diseases. (2020). Preliminary estimates of the prevalence of selected underlying health conditions among patients with coronavirus disease 2019 — United States, February 12–March 28, 2020. MMWR. Morbidity and Mortality Weekly Report, 69(13), 382–386. https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6913e2-H.pdf

Guan, W. J., Ni, Z. Y., Hu, Y., Liang, W. H., Ou, C. Q., He, J., Liu, L., Shan, H., Lei, C. L., Hui, D. S. C., Du, B., Li, L. J., Zeng, G., Yuen, K. Y., Chen, R. C., Tang, C. L., Wang, T., Chen, P. Y., Xiang, J., ... Zhong, N. S. (2020). Clinical characteristics of coronavirus disease 2019 in China. New England Journal of Medicine, 382(18), 1708–1720. https://doi.org/10.1056/NEJMoa2002032

Liu, W., Tao, Z. W., Wang, L., Yuan, M. L., Liu, K., Zhou, L., Wei, S., Deng, Y., Liu, J., Liu, H. G., Yang, M., & Hu, Y. (2020). Analysis of factors associated with disease outcomes in hospitalized patients with 2019 novel coronavirus disease. Chinese Medical Journal, 133(9), 1032–1038. https://doi.org/10.1097/CM9.0000000000000775

Farsalinos, K., Barbouni, A., & Niaura, R. (2020). Smoking, vaping and hospitalization for COVID-19. Qeios. Advance online publication. https://doi.org/10.32388/Z69O8A.8

Li, F., Li, W., Farzan, M., & Harrison, S. C. (2005). Structure of SARS coronavirus spike receptor-binding domain complexed with receptor. Science, 309(5742), 1864–1868. https://doi.org/10.1126/science.1116480

Coutard, B., Valle, C., de Lamballerie, X., Canard, B., Seidah, N. G., & Decroly, E. (2020). The spike glycoprotein of the new coronavirus 2019-nCoV contains a furin-like cleavage site absent in CoV of the same clade. Antiviral Research, 176, Article 104742. https://doi.org/10.1016/j.antiviral.2020.104742

Follis, K. E., York, J., & Nunberg, J. H. (2006). Furin cleavage of the SARS coronavirus spike glycoprotein enhances cell-cell fusion but does not affect virion entry. Virology, 350(2), 358–369. https://doi.org/10.1016/j.virol.2006.02.003

Li, W., Moore, M. J., Vasilieva, N., Sui, J., Wong, S. K., Berne, M. A., Somasundaran, M., Sullivan, J. L., Luzuriaga, K., Choe, H., & Farzan, M. (2003). Angiotensin-converting enzyme 2 is a functional receptor for the SARS coronavirus. Nature, 426(6965), 450–454. https://doi.org/10.1038/nature02114

National Institutes of Health. (2020). Novel coronavirus structure reveals targets for vaccines and treatments. U.S. Department of Health and Human Services. https://www.nih.gov/news-events/nih-research-matters/novel-coronavirus-structure-reveals-targets-vaccines-treatments

Wrapp, D., Wang, N., Corbett, K. S., Goldsmith, J. A., Hsieh, C. L., Abiona, O., Graham, B. S., & McLellan, J. S. (2020). Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation. Science, 367(6483), 1260–1263. https://doi.org/10.1126/science.abb2507

Zhao, Y., Zhao, Z., Wang, Y., Zhou, Y., Ma, Y., & Zuo, W. (2020). Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCoV. bioRxiv. https://doi.org/10.1101/2020.01.26.919985

Brake, S. J., Barnsley, K., Lu, W., McAlinden, K. D., Eapen, M. S., & Sohal, S. S. (2020). Smoking upregulates angiotensin-converting enzyme-2 receptor: A potential adhesion site for novel coronavirus SARS-CoV-2 (COVID-19). Journal of Clinical Medicine, 9(3), Article 841. https://doi.org/10.3390/jcm9030841

Leung, J. M., Yang, C. X., Tam, A., Shaipanich, T., Hackett, T. L., Singhera, G. K., Dorscheid, D. R., & Sin, D. D. (2020). ACE-2 expression in the small airway epithelia of smokers and COPD patients: Implications for COVID-19. European Respiratory Journal, 55(5), Article 2000688. https://doi.org/10.1183/13993003.00688-2020

Oakes, J. M., Fuchs, R. M., Gardner, J. D., Lazartigues, E., & Yue, X. (2018). Nicotine and the renin-angiotensin system. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 315(5), R895–R906. https://doi.org/10.1152/ajpregu.00099.2018

Yue, X., Basting, T. M., Flanagan, T. W., Xu, J., Lobell, T. D., & Gilpin, N. W. (2018). Nicotine downregulates the compensatory angiotensin-converting enzyme 2/angiotensin type 2 receptor of the renin-angiotensin system. Annals of the American Thoracic Society, 15(Suppl 2), S126–S127. https://doi.org/10.1513/AnnalsATS.201712-938MG

Chen, Y., Shan, K., & Qian, W. (2020). Asians do not exhibit elevated expression or unique genetic polymorphisms for ACE2, the cell-entry receptor of SARS-CoV-2. Preprints. https://doi.org/10.20944/preprints202002.0258.v1

World Health Organization. (2020). Tobacco free initiative: Tobacco and waterpipe use increases the risk of suffering from COVID-19. Regional Office for the Eastern Mediterranean. http://www.emro.who.int/tfi/know-the-truth/tobacco-and-waterpipe-users-are-at-increased-risk-of-covid-19-infection.html

Institute for Public Health. (2015). National Health and Morbidity Survey 2015: Report on smoking status among Malaysian adults. Ministry of Health, Malaysia. http://www.moh.gov.my/moh/resources/NHMS2015-VolumeV.pdf

Galen Centre for Health and Social Policy. (2020, February 19). Over 12 bil illegal cigarettes sold in Malaysia in 2019: Study. CodeBlue. http://codeblue.galencentre.org/2020/02/19/over-12bil-illegal-cigarettes-sold-in-malaysia-in-2019-study/

World Health Organization. (2003). World Health Organization framework convention on tobacco control. https://www.who.int/fctc/text_download/en/

He, X., Lau, E. H. Y., Wu, P., Deng, X., Wang, J., Hao, X., Lau, Y. C., Wong, J. Y., Guan, Y., Tan, X., Mo, X., Chen, Y., Liao, B., Chen, W., Hu, F., Zhang, Q., Zhong, M., Wu, Y., Zhao, L., ... Cowling, B. J. (2020). Temporal dynamics in viral shedding and transmissibility of COVID-19. Nature Medicine, 26(5), 672–675. https://doi.org/10.1038/s41591-020-0869-5

Whittaker, R., McRobbie, H., Bullen, C., Rodgers, A., Gu, Y., & Dobson, R. (2019). Mobile phone text messaging and app-based interventions for smoking cessation. Cochrane Database of Systematic Reviews, 2019(10), Article CD006611. https://doi.org/10.1002/14651858.CD006611.pub5