Coronavirus vaccines tweaked to deal with variants will be fast-tracked without compromising on safety or effectiveness, the UK’s regulator has said.

The approach will be similar to the regulatory process for the modified flu vaccine, to deal with new strains each year, with a brand new approval not required.

Scientists have previously said a Covid-19 variant resistant to the current crop of vaccines is likely to emerge at some point, but vaccines can also be adapted quickly.

The guidance states coronavirus vaccine manufacturers will need to provide robust evidence that the modified jab produces an immune response. However, lengthy clinical studies deemed not to add to the regulatory understanding of their safety, quality or effectiveness will not be needed.

The Medicines and Healthcare products Regulatory Agency (MHRA) said researchers are in a better position to measure protection by looking at antibodies in the blood after vaccination, reducing the need to wait and see whether or not people in a trial become infected with the virus.

It said this will “significantly reduce” the length of time it takes for the modified vaccine to be ready.

The guidance from the Access Consortium – a group made up of regulatory authorities from the UK, Australia, Canada, Singapore and Switzerland -requires that, as well as evidence on immune response, the modified vaccines must be shown to be safe and of the expected quality.

It says data from the original clinical trials and ongoing studies on real-world use in millions of people could be used to support any decision by the regulators.

Our priority is to get effective vaccines to the public in as short a time as possible, without compromising on safety

Dr Christian Schneider chief scientific officer at the MHRA, said: “Our priority is to get effective vaccines to the public in as short a time as possible, without compromising on safety.

“Should any modifications to authorised Covid-19 vaccines be necessary, this regulatory approach should help to do just that.

“The announcement today also demonstrates the strength of our international partnerships with other regulators and how our global work can help ensure faster access to life-saving vaccines in the UK and around the world.

“The public should be confident that no vaccine would be approved unless the expected high standards of safety, quality and effectiveness are met.”

Meanwhile, research has suggested the rate of decline in Covid-19 infections in England has slowed, with data indicating that in some parts of the country the rate has plateaued while in some places there are hints that rates are increasing.

One in every 213 people is still testing positive for Covid-19, the Imperial College London React study found.

Researchers warned that infection rates need to get as low as possible to give the vaccination programme the best chance of working.

The study also suggested that some professions have had higher rates of infection than others during the national lockdown – including teachers and transport workers.

The latest Government data – up to March 2 – shows that 20,703,615 first doses of vaccine have been administered so far in the UK.