SUMMARY: This article review looks at what is already known about SARS and MERS and uses the data and clinical studies to discuss potential vaccines and treatments for the new coronavirus, SARS-CoV-2. Compared to SARS-CoV and MERS, SARS-CoV-2 has a much lower fatality rate (2.8%). It’s highly contagious and has an R0 of 2.2-2.6, meaning an infected individual can go on to infect 2.2 to 2.6 other people. To get the R0 below 1, more than half the infections must be controlled. Eighty percent of the cases are mild or asymptomatic, but these people can transmit the virus without knowing it. Based on what we know about SARS-CoV and MERS, these viruses are able to infect epithelial cells in the respiratory system while, at the same time, preventing these infected cells from signaling the innate immune system. If SARS-CoV-2 attacks our immune systems in the same way, this could explain the long incubation period (2-11 days) and why it causes more severe symptoms in people with underlying conditions, the elderly, and those with already-compromised immune systems. It’s also thought that, like SARS and MERS, SARS-CoV-2 decreases CD4+ T-cell activity. Survivors of SARS and MERS had strong CD4+ T-cell responses and the same could be true for SARS-CoV-2. In MERS, MHC Class I and II were downgraded on APCs, causing low helper T-cell response and thus delayed seroconversion. Similarities between the already-known coronaviruses can help us develop a vaccine for SARS-CoV-2. Of course, there are still many hurdles ahead and vaccine safety is a top priority.
LESSON COMMENTS: This is an excellent article for teachers looking to teach students about SARS-CoV-2 and why the world is currently struggling with containment. The abstract and introduction can be used for lower level biology students while the immunopathology lesson is an excellent assignment for more advanced students. If teachers want, they can highlight important parts of this article for students. There are also easy to understand charts that teachers can use to talk about this pandemic with younger students in the middle school. Some prior knowledge of the immune system and respiratory system is necessary for all students.
Prompetchara, E., Ketloy, C., & Palaga, T. (2020). Immune responses in COVID-19 and potential vaccines: Lessons learned from SARS and MERS epidemic. Asian Pacific Journal of Allergy and Immunology, 38(1), 1–9. doi: 10.12932/ap-200220-0772