Pfizer and BioNTech have confirmed that their vaccine is effective against both the UK and South African variants of Covid.
The study - which was carried out by Pfizer and the University of Texas Medical Branch - analysed blood taken from people who had received the vaccine.
According to early findings, there was a small reduction in antibody levels against the South African variant, which suggests that the vaccine would only lose a marginal amount of effectiveness, and would still be able to neutralise the virus.
The research also showed good results against numerous key mutations from the UK variant of the virus.
However, the findings are currently limited, as the full set of mutations found in the new South African variant has not been considered, and the research is also yet to be peer reviewed.
Pfizer and BioNTech have said that these study findings suggest there is no need for a new vaccine for the new mutations, but have said they are prepared and in a position to respond if further evidence does show that the current vaccine does not work on a certain Covid variant.
Study author, Pei-Yong Shi, said that researchers are currently engineering a virus with the full set of mutations from both the UK and South African Covid variants. The first results from this are expected in around two weeks.
These early findings come after early laboratory tests have also shown that Moderna's vaccine appears to work against new Covid variants found in the UK and South Africa.
Scientists from the US pharmaceutical company have said that the tests suggest antibodies triggered by the vaccine can recognise and fight the new coronavirus variants.
However, further studies are needed in order to be able to confirm that this is true for people who have received the vaccine.