501.V2, another unfortunate coincidence!

Right after we learnt about B.1.1.7, another highly infectious variant of SARS-CoV-2 has captured public attention before Christmas. This variant was known as ‘501.V2’, which was believed to be from South Africa.

According to Dr Julian Tang from the University of Leicester, 501.V2 was characterized by eight mutations, including three important ones, namely N501Y, E484K, and K417N, found in the spike protein. Some highlights of these mutations are as follows,

  1. N501Y, which was one of the mutations present in B.1.1.7. This mutation has been demonstrated to make the virus more infectious and deadly in the laboratory;
  2. E484K, similar to N501Y, was related to the binding between the viral spike protein and the host’s receptor (ACE2). This uncommon mutation was believed to make the virus more infectious;
  3. Since both N501Y and E484K were present in 501.V2, it was likely to be more infectious than B.1.1.7 (by simple deduction);
  4. K417N was suggested to influence on the interaction between the virus and the neutralizing antibodies (NAbs). Given that NAbs can prevent the virus from binding to its host, this mutation could implicate at least three scenarios: first, recovered patients could get infected by N501.V2 again; second, people could get infected by this variant after vaccination; third, the efficacy of COVID-19 antibody therapy could be reduced.

The highlights above are based on logical speculation, providing some directions of further research. Theoretically, for example, we also believe that a virus, such as SARS-CoV-2, is likely to become more infectious, yet less deadly or even asymptomatic during its evolution; in other words, COVID-19 is eventually going to be similar to seasonal flu.

In medicine, nonetheless, we have to rely on the data from clinical trial for the most reliable conclusions; scientists and physicians should continue to pay attention to these two new variants: in reality, it is often a matter of probability or degree; it is not simply all-or-nothing. Moreover, different individuals may have different responses because of the genetic and environmental factors. Sometimes it can be more complicated than expected.

Good luck to South Africa!

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