Reflections on a Year of SARS-CoV-2

As we are writing this editorial 12 months following the publication of “The 2019 Novel Coronavirus: A Crown Jewel of Pandemics?”, there are 96 million cases with over two million total deaths, a public health tragedy of staggering proportions. The early stages of the pandemic were characterized by scientific uncertainty, with many authors postulating hypotheses about the transmission of SARS-CoV-2, the appropriate medical treatment, and the most effective public health measures. In retrospect, many of the early takes on coronavirus ended up being incorrect. Since January 2020, science has advanced at a breathtaking pace and the disease caused by SARS-CoV-2 has taken on dimensions few of us anticipated. In this piece, we aim to reflect on the last year, discussing aspects of the pandemic that the scientific community correctly anticipated, and highlighting where we went wrong.

For the SARS-CoV-2 pandemic to have taken on its current dimensions, two conditions must have been met: first, a viral transmission pattern that was unusually infectious, and second, an ineffective public health response. Last January, we anticipated SARS-CoV-2 to spread similarly to MERS-CoV and SARS-CoV, mainly after infected patients started presenting respiratory tract symptoms. We were just beginning to appreciate the potential for human-to-human transmission. However, one of the most surprising and alarming discoveries was the fact that SARS-CoV-2 could spread asymptomatically. In the early stages of the pandemic, with the number of cases small, our ability to identify asymptomatic transmission was impaired leading to a drastic underestimation of the viral transmission potential of the virus. Furthermore, the high reproductive number (R0), combined with the relatively mild disease severity, led to efficient spread. Unlike SARS-CoV and MERS-CoV, where the disease severity and viral dynamics contained the outbreaks and decreased their likelihood of becoming pandemics, the SARS-CoV-2 outbreak hit the Goldilocks zone of infectivity and severity.