How Does COVID-19 Differ from Previous Epidemics

By Linya Thng

Throughout history, a multitude of pandemics have emerged. Decades of enhancing medical and scientific knowledge in the socio- political context has brought us a step closer in effectively identifying, controlling and eradicating a pandemic. According to the World Health Organization (WHO), a “pandemic” is defined as the worldwide spread of a disease (Kelly, 2011). This article focuses on analysing the current pandemic to historical pandemics. 

Originating in the city of Wuhan, Central China, Coronavirus disease 2019 (COVID- 19) is known to be a causative agent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This newly identified SARS-CoV-2 is associated with its tragic outbreak, which has spread to 72 countries to date, posing a serious threat to public health. Belonging to the subfamily Orthocoronavirinae, Coronaviruses (CoVs) are characterised as enveloped, positive sense RNA viruses and morphologically known for its spike structure projected from their surface, its large RNA genome and replication strategy (Shereen et al., 2020). In this pandemic, a high proportion of the population can be asymptomatic – meaning they are unaware that they have been infected with the disease. This uncertainty in diagnosis decreases the probability of individuals getting tested and reporting positive cases to health organizations, resulting in underestimated statistics. Based on the statistics in temperate regions, regular flu and cold viruses appear to have a seasonal pattern of infectiousness. The weather conditions and modes of transmission along with the number of susceptible hosts contributes to the seasonal pattern. However, in the case of COVID-19, this is not applied (Hiscott et al., 2020).

Without a doubt, the most menacing of the pandemics in recent history, is the Spanish Flu. If you were to produce a graph of the number of deaths throughout the 20th century of non-war related deaths, you would see a clear peak dominating in the years of 1918 to 1919. This huge peak consists of an unthinkable 50 million lives lost to the Spanish flu also known by its technical name, H1N1 (Hiscott et al., 2020). In 1957-1968, the Asian flu swept through the eastern subcontinent claiming over a million lines. The virus originated as a new variant of the avian flu and was named the H2N2 virus. Not only did it manage to kill such a large number of people predominantly in China where it is assumed to have spread, but with limited international transportation at the time, the virus only spread to the United States where it claimed a further 116,000 lives (Deming & Chen, 2020).

In a rather vicious foreshadowing of the SARS-CoV-2 pandemic, the SARS-CoV epidemic of 2002-2004 killed almost 800 people. Despite this number being microscopic in scale compared to some of the other viruses mentioned in this article, the virus shows a catastrophic failure of the Chinese government in the prevention of COVID-19. This is because SARS-CoV and SARS-CoV-2 are identical in origin and can both be traced to Chinese wet markets that are immensely unhygienic and prone to disease spread. Despite the clear biohazard posed by the SARS epidemic of 2002, nothing was done by the government to ban the use of wet markets in China. Meaning the next deadly virus to come out of these wet markets was a disaster waiting to happen (Li et al., 2020). A more recent threat that was the result of an epidemic in western Africa is the Ebola virus. The Ebola virus outbreak occurred in 2014-2016 and caused over 11,000 deaths in the African countries of Liberia, Sierra Leone and Guinea (Deming & Chen, 2020). Although this number might not seem very high, besides SARS-CoV-2 kills this number of people in a single day, the fatality rate for a virus was astronomical. 40% of those who caught the Ebola virus died, with over 60% of cases hospitalised. The virus is predicted to have originated from bats and spread through human-to-human transmissions through direct contact of blood or bodily fluid. 

Amidst this pandemic, we can only continue to hope the coordinated global effort among researchers, international organizations, and countries will address the current pandemic and enhance our knowledge on this virus and its speed dynamics.

References:

Kelly, H. (2011) The classical definition of a pandemic is not elusive. Bulletin of the World Health Organization; Bull World Health Organ. 89 (7), 540-541. Available from: doi: 10.2471/BLT.11.089086.

Shereen, M. A., Khan, S., Kazmi, A., Bashir, N. & Siddique, R. (2020) COVID-19 infection: Origin, transmission, and characteristics of human coronaviruses. Journal of Advanced Research; J Adv Res. 24 91-98. Available from: doi: 10.1016/j.jare.2020.03.005.

Hiscott, J., Alexandridi, M., Muscolini, M., Tassone, E., Palermo, E., Soultsioti, M. & Zevini, A. (2020) The global impact of the coronavirus pandemic. Cytokine & Growth Factor Reviews. 53 1-9. Available from: doi: 10.1016/j.cytogfr.2020.05.010.

Deming, M. E. & Chen, W. H. (2020) COVID-19 and Lessons to Be Learned from Prior Coronavirus Outbreaks. Annals of the American Thoracic Society; Ann Am Thorac Soc. 17 (7), 790-794. Available from: doi: 10.1513/AnnalsATS.202002-149PS.

Li, H., Liu, S., Yu, X., Tang, S. & Tang, C. (2020) Coronavirus disease 2019 (COVID-19): current status and future perspectives. International Journal of Antimicrobial Agents; Int J Antimicrob Agents. 55 (5), 105951. Available from: doi: 10.1016/j.ijantimicag.2020.105951.