Early results from laboratory studies have suggested that antibodies produced in response to the Pfizer vaccine may be less effective at binding to the B.1.617 variant. The same study also looked at 33 cases of Covid-19 in healthcare workers in Delhi who had received two doses of the AstraZeneca vaccine, finding that the majority (19) of these cases were due to the B.1.617 variant.
The B.1.617 variant has several important mutations which may make it easier to pass on, or make it resistant to the immune response to the virus, including:
The L452R mutation, which may help the virus escape the immune response, including antibodies (which attach to the virus to help neutralise it) and immune cells (which help to directly attack the virus and infected cells). There is also some evidence it can affect how well the virus binds to ACE2 receptors on the surface of our cells. As this is a vital step in the virus getting into our cells, this mutation could potentially make it more infective.
The P681R mutation – which is also present in other variants, including the Kent strain. It’s thought that this mutation may make it easier for the virus to spread.
The B.1.617.1 and B.1.617.3 sub-lineages also carry the E484Q mutation, which is similar to the E484K mutation first identified in the South African strain. There is evidence that this mutation may help the virus escape the immune response.