As viruses create more of themselves within a host, they are prone to copying errors. These mutations or recombinations are single-point changes in the virus’ genetic code. Most of these changes do nothing, but others can lead to increased transmissibility, drug resistance, immune escape (either innate or vaccine), or the emergence of a new disease. (1) Mutations can go in favor of the virus or the host. For example, the SARS-CoV virus may have developed a mutation that slowed its spread in humans. (2)

Influenza, HIV, and SARS-CoV-2, however, mutate differently. Influenza viruses mutate annually to the point where they escape detection by the immune system and make previous vaccines ineffective. HIV mutates enough to where it becomes resistant to antiviral drugs, for example. The SARS-CoV-2 virus has recently mutated to become more transmissible.

D614G was the first mutation of note as it appeared in more and more cases globally and is now ubiquitous. It has since been shown to infect cells more efficiently. (3,4)

N501Y, present in the receptor-binding domain of spike is believed to increase the spike protein’s binding affinity for the ACE2 host receptor. This mutation is present in three newly identified variants of SARS-CoV-2: UK 501Y.V1, South Africa 401Y.V2, and Brazil 501Y.V3. These variants have been observed to displace other lineages and are actively being studied. The UK variant transmits at a higher rate and the Brazil variant reinfects previous COVID-19 patients.(5,6,7)

The E484K mutation present in both the South Africa and Brazil variants has been shown to be resistant to convalescent plasma neutralization. (7,8)

The L452R mutation has been increasingly identified in California. This mutation, as well as several others, has shown to be resistant to some neutralizing monoclonal antibodies. (9)

ProSci, the leading supplier of SARS-CoV-2 antibodies and proteins, enhances global research on the effects of these mutations through its extensive catalog. Current research utilizes this catalog of Spike Variants antibodies and Variants recombinant proteins.


1 Sanjuan, R. et al. Cell. Mol. Life Sci. (2016) 73:4433-4448.

2 Muth, D. et al. Sci. Rep. 8, 15177 (2018).

3 Korber, B. et al. Cell 182, 812–827 (2020).

4 Zhang, L. et al. Nat. Commun. 11, 6013 (2020).

5 Rambaut, A. et al. (2020)

6 WHO Disease Outbreak News

7 Resende, P.C. et al. (2021).

8 Andreano, E. et al. bioRxiv. Preprint (2020)

9 Li, Q. et al., Cell 182, 1284-1294 (2020).