The Evolution of Pandemics

by Sam Sun

The COVID-19 pandemic has often been compared with prior infectious disease outbreaks, such as those caused by SARS, Ebola, MERS, H1N1, and the 1918 influenza virus. In the past, the spread of a virus could often be contained with public health tools alone (e.g. SARS outbreak in 2002-2004). These tools have become familiar to the public and include “containment” strategies such as testing, contact tracing, & quarantine, and “mitigation” strategies such as hand hygiene, masking, & social distancing [1].

Unfortunately, SARS-CoV-2 continues to spread. While this can partly be attributed to our global interconnectivity and variations in governmental responses to the COVID-19 pandemic, the underlying biology of SARS-CoV-2 makes “containment” difficult. Unlike SARS, which did not induce significant viral shedding until several days after symptom onset, SARS-CoV-2 may spread prior to symptom onset or via asymptomatic people [2-3].

While public health tools continue to be critical, the likelihood of SARS-CoV-2 disappearing is low. In particular, a flood of public-private partnerships and industry resources have poured into drug and vaccine development for SARS-CoV-2. For the most part, this is unique compared to prior viral outbreaks, which often disappeared before vaccines could be developed. On the other extreme, even the basics of modern medicine did not exist during the 1918 influenza pandemic; Alexander Fleming would not discover penicillin until a decade later in 1928. The 1918 influenza pandemic only disappeared with herd immunity and evolution of the H1N1 influenza A virus into less virulent strains, after it had infected a third of the world’s population and killed tens of millions of people.

Figure 1: Role of protective strategies in viral outbreaks, by scale of outbreak.

Where does that leave us? SARS-CoV-2 might go away if the virus evolves to become less virulent [4]. Herd immunity is possible but the human cost of life and suffering would be astronomical. Therefore, therapeutics and vaccines will be crucial to mitigating the damage caused by SARS-CoV-2. Indeed, if the virus becomes endemic like the seasonal flu [5], we may continue to use therapeutics against SARS-CoV-2 even with the development of an effective vaccine.

Figure 2: We believe that public health measures must be augmented with novel therapeutics and vaccines to control and end the COVID-19 pandemic.

Therefore, given its importance to the pandemic and potentially future outbreaks of SARS-CoV-2, our initial focus as inDemic Foundation is to curate and analyze data on promising developmental therapeutics and vaccines for the SARS-CoV-2 virus.


[1] Walensky, Rochelle P., and Carlos Del Rio. “From mitigation to containment of the COVID-19 pandemic: putting the SARS-CoV-2 genie back in the bottle.” Jama (2020).

[2] Day, Michael. “Covid-19: four fifths of cases are asymptomatic, China figures indicate.” (2020).

[3] Petersen, Eskild, et al. “Comparing SARS-CoV-2 with SARS-CoV and influenza pandemics.” The Lancet Infectious Diseases (2020).

[4] Grubaugh, Nathan D., Mary E. Petrone, and Edward C. Holmes. “We shouldn’t worry when a virus mutates during disease outbreaks.” Nature Microbiology 5.4 (2020): 529-530

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