Coronavirus Mutations Update

SARS-CoV-2 N501 mutation lineages (nextstrain.org)

Updated: June 2021
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A brief update on the new coronavirus mutations, including the ‘British’, ‘South African’ and ‘Brazilian’ variants (i.e. N501Y.V1-V3), and evidence of their properties:

  1. There is some evidence that some of the new variants are somewhat more transmissible, although suspected higher viral loads have not been confirmed. However, this initial, relative advantage in transmissibility may decrease over time, as more people get infected.
  2. New coronavirus variants do not produce any different symptoms, and the evidence that they might be more virulent or lethal remains rather weak. In general, covid may be more severe in winter than in spring and summer (e.g. due to lower vitamin D levels).
  3. There is currently no evidence that new variants preferentially infect children.
  4. There is also no evidence that measures such as lockdowns or face masks work any better or any worse against new variants. Many places affected by new variants have seen a decrease in cases (e.g. Denmark, Portugal, the Netherlands, South Africa and the UK).
  5. There is some evidence of partial immune evasion by new variants, which is well known from influenza viruses and from other coronaviruses, and which may enable reinfections – with or without symptoms – in some people, and first infections in more people.
  6. There is also clear evidence that some of the current vaccines are less protective against some of the new variants. These vaccines may require regular updates or boosters.
  7. But there is no evidence that early and prophylactic treatment is any less effective against new variants, as it targets virus replication, cell entry, or disease progression.

See also: Coronavirus Variants Dashboard (covariants.org)

Update: The summer wave driven by the ‘Indian variant’ (June 2021)

Illustrations

Figure 1: Coronavirus escape mutations in new virus variants

Coronavirus escape mutations against major antibody classes 1 to 3 in new coronavirus variants. Currently, no variant combines all three escape mutations. If a new strain manages to escape all three major antibody classes, this “would be a worrying development, and should be monitored closely” (Greaney et al., page 22).

Lineages: B.1.1.7 is British, B.1.351 is South Africa, P.1-2 is Brazil, B.1.429 is California, B.1.526 is New York. RBD: receptor binding domain.

Coronavirus escape mutations against major antibody classes 1 to 3 in new coronavirus variants. Currently, no variant combines all three escape mutations (Greaney et al.)
Figure 2: Coronavirus mutations and their effect on ACE2 receptor binding affinity

Coronavirus mutations and their effect on ACE2 receptor binding affinity (Starr et al.). It is possible that higher binding affinity may increase virulence or infectiousness, but it may also decrease it. x is SARS-CoV-2 (original variant), o is SARS-CoV-1. The British variant, for instance, has a mutation from amino acid 501N to 501Y, which increases receptor binding affinity (blue field).

Coronavirus mutations and their effect on ACE2 receptor binding affinity (Starr et al.)
Figure 3: RNA vaccines: Reduced neutralization against new virus variants

Covid RNA vaccines: reduction in neutralization of variants (x-fold reduction). P.1/P.2: “Brazilian” variants; B.1.351.V1-3: “South African” variants (Source: Garcia-Beltran).

Covid RNA vaccines: Reduction in neutralization of variants (x-fold reduction). P.1/P.2: “Brazilian” variants; B.1.351.V1-3: “South African” variants (Source: Garcia-Beltran)
Figure 4: Reduced effectiveness of some monoclonal antibodies

Reduced effectiveness of monoclonal antibodies casirivimab, bamlanivimab and REGN10989 against the South African and Brazilian coronavirus variants (Hoffmann et al)

Reduced effectiveness of monoclonal antibodies casirivimab, bamlanivimab and REGN10989 against the South African and Brazilian coronavirus variants (Hoffmann et al)

See also


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