Overview and Implications
The recent COVID-19 pandemic has become one of the leading causes of death in the U.S, with 1,528,235 cases reported by the CDC as of May 20, 2020 with most likely underestimates the true infection rate due to asymptomatic patients. Thus, identifying the impact carriers of COVID-19 could have on communities is significant to managing and containing the virus.
In this study, Hu et al. observed 24 patients who were carriers for COVID-19, meaning that they displayed little to no symptoms but tested positive for the virus. The study followed each patient’s clinical outcome and transmission data to support that, while none of the cases developed severe symptoms even with different types of treatment, they were able to transmit the COVID-19 infection that produced severe symptoms, such as pneumonia, in new cases.
With evidence supporting asymptomatic cases as a dangerous source of COVID-19 infections, this should give insight into how communities should act in order to prevent continued and future outbreaks. Most clinics turn away those who do not have moderate to severe symptoms which gives those who are asymptomatic or have light symptoms a false sense of safety. However, the implications of this study may be limited due to lack of testing within the U.S. for asymptomatic cases, though hopefully research into the impacts of these types of cases may encourage increased testing in the U.S.
The article provides multi-faceted case studies of 24 asymptomatic COVID-19 patients. In addition to detailing their treatments and transmission data, it also explains their laboratory results and how their CT scans differ from uninfected patients. This can give us a more detailed understanding of the mechanism of COVID-19 infection and protective factors those who are asymptomatic have.
Although this study provides useful data that can be applied to how the government implements measures against COVID-19, the sample size is relatively small and must be corroborated by large-scale, multicenter studies. Furthermore, the paper could have provided more in-depth background about isolation periods and quarantine practices into how to protect against both symptomatic and asymptomatic patients. Nevertheless, the small sample size shows how just a few individuals who are not following social distancing guidelines can propagate the disease unknowingly.
Since the pandemic is currently affecting nations across the world, a large portion of immunology and infectious disease research is directed at COVID-19, especially preventative and treatment options. In addition to working towards a vaccine, future research should be directed at looking at and limiting how the virus is transmitted from host to host. For example, determining the period of time during which the virus is most likely to be transmitted from a host may be instrumental in maximizing the effects of quarantine practices. Even when quarantine is over and we have a vaccine, there must be public safety guidelines to prepare for the next outbreak.
Hu, Z., Song, C., Xu, C., Jin, G., Chen, Y., Xu, X., Ma, H., Chen, W., Lin, Y., Zheng, Y., Wang, J., Hu, Z., Yi, Y., & Shen, H. (Mar 2020). Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing, China. Sci China Life Sci, vol. 63(5), pp. 706-711. doi:10.1007/s11427-020-1661-4.
Cases in the U.S. (2020, May 20). Center for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/cases-in-us.html.