The COVID-19 vaccine developed by Pfizer and BioNTech is likely to protect against a more infectious variant of the virus discovered in Britain which has spread around the world, according to results of further lab tests released on Wednesday.

The encouraging results from an analysis of the blood of participants in trials are based on more extensive analysis than those released by the U.S. drugmaker last week.

Last week, Pfizer said a similar laboratory study showed the vaccine was effective against one key mutation, called N501Y, found in two highly transmissible new variants spreading in Britain and South Africa.

The latest study, posted on bioRxiv.org but not yet peer-reviewed, was conducted on a synthetic virus with 10 mutations that are characteristic of the variant known as B117 identified in Britain.

Among the 11 authors of the study are Ugur Sahin and Oezlem Tuereci, co-founders of BioNTech. Sahin is chief executive and his wife Tuereci is chief medical officer.

It provides further hope as record numbers of daily deaths from COVID-19 are reported in Britain, which is believed to be driven by the more transmissible variant. It also means vaccine development would for now not have to start all over again.

But the virus needs to be continuously monitored to check that changes maintain protection by vaccines, the study said

For the test, blood samples drawn from 16 vaccinated participants in prior clinical trials were exposed to a synthetic virus called pseudovirus which was engineered to have the same surface proteins as B117, as characterised by 10 hallmark mutations.

The antibodies in the blood of the volunteers given the vaccine, known as Comirnaty, or BNT162b2, neutralised the pseudovirus as effectively as the older coronavirus version that the product was initially designed for.

Experts said the findings were reassuring and not surprising and result from similar studies on the South African variant would be keenly watched.