Are all new variants the same?
They all share a remarkably similar set of mutations in the virus’s spike protein – the part that binds to human cells – but they are not identical. All emerged in areas where recent peaks in Covid cases have occurred.
Why did they arise at the same time?
Scientists are not sure. It is speculated that they are the product of common evolutionary pressures. One theory is that patients with Covid for a prolonged period allow the virus to mutate more efficiently. The UK, South Africa and Brazil have many such cases.
Can they escape vaccines?
Pfizer and AstraZeneca believe their vaccines will still work against the UK variant. The jury has yet to decide on the other two. Some laboratory work suggests that the South African variant may end up avoiding existing antibodies (produced by vaccines or a natural infection) at some point. However, experts say it is unlikely that a vaccine will suddenly stop working. They are more likely to become less effective in increments as the virus changes.
Is this pattern normal?
Yes, respiratory viruses tend to “fluctuate” over time and vaccines need to be constantly adjusted to keep up with them. This happens every year with the seasonal flu vaccine, for example.
How simple is the vaccine update process?
In theory, it should be quite simple. As long as the changes that need to be made to the vaccines are modest (only four or five changes to the more than 1,000 amino acids in the peak protein), then new vaccines can be produced quickly and without long regulatory approval. The new RNA vaccines, like the one manufactured by Pfizer, can also be exchanged more quickly than conventional vaccines.