Over the years, I insisted on offering classes about microorganisms and infectious diseases not only to Secondary School Students, but also to Undergraduate and Postgraduate Students, for a reason to make sure my students knew what they had to know about infectious diseases. Intuitively, I believed that this knowledge was going to be useful for all of us.

In BBMS5100 Perspectives in Biomedical Sciences, for example, my lecture was designed to present a comprehensive overview of the biochemistry of infections, in which 1) the mechanisms of bacterial pathogenesis, 2) the mechanisms for bacteria to escape the immune system, 3) the mechanism of viral pathogenesis, 4) the general principles of bactericidal and bacteriostatic agents, and 5) the major mechanisms of antiviral agents were covered.

For instance, in the lecture held on 29 October 2019, we briefly mentioned coronavirus as an RNA virus; together with other important topics, such as 1) the basic structure of a viral particle, 2) viral replication cycle, 3) tissue trophism (that is, target tissue of the virus), 4) spike protein and viral attachment protein (VAP), 5) viral genetics, 6) the six stages of viral pathogenesis with the four typical pathogenic mechanisms, 7) the progression and patterns of various viral infections, 8) mechanisms of viral transmission, and 9) major mechanisms of antiviral agents, including i. synthetic nitrogenous base analogues (like ribavirin and remdesivir), ii. protease inhibitors (like anti-HIV drug), iii. inhibitors of viral uncoating (like antimalarial drug), and iv. type I interferon (that is, immunomodulators).

Yet, some further advanced topics were not discussed in my classes (because of time constraint). During my undergraduate and postgraduate education, I spent a lot of time in the field of immunobiology; from the perspectives of an immunologist, I noticed some important findings from Prof Yuen Kwok-Yung and other scientists: with proper protective measures, the first outbreak of covid-19 seldom infects the whole population, resulting in, for example, only ~5% of the population to develop the immunity against the virus (these empirical findings seemed to be quite different from the mathematical prediction proposed by computer modeling). Practically speaking, it takes time for us to develop the ‘herd immunity‘, which could cost up to >5 years (based on the experience of the H1N1 pandamic in 2009).

The findings suggested that we should be highly cautious and be well prepared for the possibility of a second outbreak later in 2020!