The UK medicines regulator is in discussions with coronavirus vaccine manufacturers about “potential modifications” that may be needed to ensure their jabs protect against new variants of the virus.
The Medicines and Healthcare products Regulatory Agency (MHRA) said there was no evidence that vaccines failed to work against the new variants that emerged in recent months, but said it had made the issue a priority.
AstraZeneca, which has partnered with Oxford University to manufacture a Covid-19 vaccine, said scientists had started work on the steps needed for rapid development of a modified vaccine in case it was required.
“It is known that viruses constantly change through mutation, leading to the emergence of new variants,” an AstraZeneca spokesperson said. “These changes are being monitored closely by scientists.
“The University of Oxford and labs across the world are carefully assessing the impact of new variants on vaccine effectiveness, and starting the processes needed for rapid development of adjusted Covid-19 vaccines if these should be necessary.”
Work is under way at Public Health England’s Porton Down laboratory and specialist academic facilities to find out whether current vaccines are less protective against the new highly transmissible variants, such as those first detected in the UK and South Africa.
Initial studies suggest that antibodies from former Covid patients, and those induced by some vaccines, are still broadly effective against the B117 variant found in the UK, but the 501Y.v2 variant that has spread widely in South Africa appears to be more resistant. The protective effect of T-cells, which are induced by vaccines and previous Covid infections, will also be important but is still being investigated.
Researchers are concerned about mutations in the spike protein that covers the surface of the virus. Since this is the target of most antibodies, mutations that substantially change the shape of the spike can potentially make the virus more resistant to immunity acquired from the vaccine or an infection in the first wave.
“We currently have no evidence that the vaccines being used do not work against the new Covid-19 strains, but we are making this issue a priority,” an MHRA spokesperson said. “We are in discussion with vaccine manufacturers on potential modifications that may be needed for current vaccines to be effective against new variants, if required.”
Because viruses evolve, the emergence of new variants is expected, and vaccine manufacturers anticipate having to update their vaccines at some point, or even regularly. Influenza vaccines are updated each year to ensure the jabs people receive most closely match the flu that circulates in the season ahead. A decision on which flu vaccine to make takes place around February. Vaccine production and testing then takes several months with a licence given only when the regulators have reviewed quality, safety and efficacy data.
The MHRA is consulting its independent expert working group of the Commission on Human Medicines to decide how it will regulate any modifications to the existing Covid vaccines. It is likely that “bridging studies” will be needed to give regulators confidence that any modifications have no safety implications.
“We can say at this stage that it is unlikely that a full new approval process will be needed,” the spokesperson said. “No vaccine will be authorised for supply in the UK unless the expected standards of safety, quality and effectiveness are met.”
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