Matter Magazine: Why Is COVID-19 So Hard To Beat?
By Krish Patel
COVID-19 has dramatically altered the Exeter experience: remote learning, cancelled trips, Zoom Harkness tables, socially distanced dorm events and more. Back when the pandemic emerged, even experts suggested that our global predicament would be over in a matter of months. But now, with the hope vaccines bring, why might COVID-19 still be a threat? Let’s take a look at the virus itself, and why it’s so good at keeping us locked away at home, wearing the strange combination of nice shirts and pajama pants, enthusiastically waving to laptop screens.
SARS-CoV-2, like all viruses, mutates all the time. Mutations are genetic errors that a virus incurs when it replicates. Coronaviruses tend to mutate slower than most other viruses due to a built-in proofreading mechanism that corrects these errors, called nucleic acid polymerase. Coronaviruses have a specific form of polymerase called RNA-dependent RNA polymerase (RdRP). RdRP is responsible for catalyzing the replication of the virus’ RNA, while also verifying that the correct nucleic acid base pairs are present in their designated locations.
However, despite these mechanisms, errors are inevitable. RdRP can sometimes allow the RNA to replicate irregularly, accumulating mutations. For most of the time, these changes are minute, but if particular base pairs of the RNA are altered, a competitive advantage (e.g. increased infection rate, increased health effects, etc.) could arise.
For SARS-CoV-2, mutations have been arising since its origin. However, because changes with significant effects are rare, we have only recently identified certain variants that have prevailed.
As of now, there are three major coronavirus variants: variant B. 1.1.7 (which originated in the United Kingdom), variant 1.351 (which originated in South Africa) and variant P.1 (which originated in Brazil). Even though each variant has attributes that make it superior to SARS-CoV-2, the pulmonary impacts remain similar. The actual cause for these viruses’ differences is the Reproductive Number, dented R.
According to the CDC, “The basic reproduction number… is an epidemiological metric used to describe the contagiousness or transmissibility of infectious agents.” Several studies gave SARS-CoV-2 an R-value of around 0.86, whereas variant B. 1.1.7 has the more concerning R-value of around 1.38. With this rating, variant B. 1.38 can potentially double the number of cases in a population in only nine days, as compared to SARS-CoV-2’s 30+ days.
Variant B. 1.1.7 originated months before its counterparts, and therefore has spread further around the globe. The other variants are still somewhat localized to specific regions, and with the growing number of travel restrictions, their spread is expected to be reduced. However, coupled with this glimmer of hope is the fact that the variant P.1 contains sets of additional mutations that may affect its ability to be recognized by antibodies, meaning that the grueling work to create treatments and vaccines will need to continue. Companies like Moderna and Pfizer have already begun to work on a vaccine booster shot to confront this issue, although little is known about how the new variants might impact humans.
While vaccine distribution has generated optimism for herd immunity and a reopening of public spaces, we must remember that the threat of coronavirus remains. As long as the virus exists in our population, the possibility of a new variant threatens to start another pandemic. We must ensure serious precautions are taken to prevent a cyclical life of the virus (the creation of a new variant every six months) that would send us back to square one.
Exonians, remember to stay safe during the pandemic both on and off campus. We can optimize the scientific advances against COVID-19 by washing hands, social distancing, and wearing masks, which have been scientifically proven to slow viral spread. As we come back to campus in just a short few weeks, following these guidelines can keep our community safe and COVID-free.
For latest news and information on how to help prevent the spread of COVID-19, please visit the Centers for Disease Control at https://www.cdc.gov.