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:
- There is currently no evidence that new variants are more virulent or more lethal or that they produce any different symptoms. The fact that covid is generally more severe in winter than in spring and summer was to be expected (e.g. due to lower vitamin D levels).
- There is clear evidence that the new variants are currently about 50% more transmissible, although suspected higher viral loads have not been confirmed. However, this relative advantage in transmissibility may decrease over time, as more people get infected.
- There is currently no evidence that new variants preferentially infect children.
- 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 already seen a decrease in cases (e.g. Denmark, Portugal, the Netherlands, South Africa and the UK).
- Even places with a near 100% proportion of new variants, such as parts of England, managed to drive down infection rates, which speaks against an out-of-control “new pandemic”.
- The fact that ACE2 cell receptor affinity is higher in new variants does not mean that their virulence or infectiousness must be higher; they may as well be lower or unchanged.
- The fact that a new variant may replace an older variant is well known from previous Sars-Cov-2 variants (e.g. D614G and the ‘Spanish variant’) and also from seasonal influenza viruses. This effect does not necessarily require higher intrinsic contagiousness.
- The fact that places with a small first wave are seeing a stronger second wave (e.g. Portugal) was to be expected and does not require new variants – e.g. many Eastern European countries and some US states saw stronger second waves of the original variant.
- There is, however, clear 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.
- Immune evasion may explain why some places already hit hard in spring, such as South Africa or Manaus in Brazil – both of which had an antibody seroprevalence of about 30% until summer (but not 70%, as some claimed) – are seeing a strong second wave driven by new variants.
- 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.
- 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)