Q and A


What are the main COVID-19 variants and will they affect vaccines?


Although all viruses change and evolve the new coronavirus variants are especially important because we now have effective vaccines.

By February 2021, several well-publicised variants have been described with brief characteristics listed in Table 1.

Although they were first reported in one country most were soon also reported in others. Some of these variants are transmitted more easily and some might affect how well vaccines work. This impact is still being studied but an early paper already reports a small but significant impact. [1]

Currently, the most serious is called B.1.351 (initially reported in South Africa).

However, all manufacturers are already testing updated versions of their vaccines against these new variants.

Table 1: Key variants and predicted impact on current vaccines

Date reported Original region Name Mutation Impact Comment
April 2020 Global D614G.1 S-protein Quickly became main global strain. Increased the replication efficiency and transmissibility. NAbs still recognised
June 2020 Denmark By November reported in more than 200 mink farms and in humans. >1.4 million animals culled. Seven unique variants in S protein. Mink-related outbreaks also reported in the Netherlands, Spain, Sweden, Italyand the US. These are small and largely contained reports. No information on impact on vaccines.
August 2020. UK (Kent) B.1.1.7

[also 20I/501Y.V1 and VUI 202012/01 – variant under investigation)

N501Y S-protein Expanded in UK Nov to Jan. >600 cases reported in 33 US states. Increased transmission.

NAbs still recognised by Oxford, Pfizer and Moderna vaccines. Reduces sensitivity to neutralising Abs.

October 2020. South Africa B.1.351 (also as 20H/501Y.V2) 17 unique mutations in both S and N terminal including K417N, E484K and N501Y). Already reported in 30 countries including 5 cases in US. E484K might cause some reduction in NAb but impact is not fully known. Reduced efficacy has been reported to Pfizer, Moderna, Oxford and Novavax vaccines.

Reduces sensitivity to neutralising Abs.

January 2021. Brazil (but detected in travelers to Japan). P.1 (also as 20J/501Y.V3)


(Variants of B.1.1.28.)

More sequence changes in both S and N terminal including K417N, E484K and N501Y). Already reported in many countries including Japan, Brazil, Germany and the US. Not yet known.
January 2021. California CAL.20C


ORF1a: I4205V, ORF1b:D1183Y, S: S13I, W152C, L452R. So far limited to the US. Impact not yet known.


  1. Wang Z et al. mRNA vaccine-elicited antibodies to SARS-CoV-2 and circulating variants. bioRxiv preprint. DOI:10.1101/2021.01.15.426911. (30 January 2021).

Further reading

A guide to emerging SARS-CoV-2 variants. The Scientist. (26 January 2021).

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