The UK health authorities on Saturday approved a second bivalent vaccine to be used as a booster vaccine to target both the Omicron and original strain of COVID-19.

The Medicines and Healthcare products Regulatory Agency (MHRA) said the updated booster vaccine made by Pfizer/BioNTech was found to meet its standards of safety, quality and effectiveness.

The jab targeting two coronavirus variants has been approved for use in individuals aged 12 years and above. In each dose of the booster vaccine called Comirnaty bivalent Original/Omicron , half of the vaccine (15 micrograms) targets the original virus strain and the other half (15 micrograms) targets Omicron (BA.1).

The clinical trial of the Pfizer/BioNTech bivalent vaccine showed a strong immune response against the Omicron BA.1 variant as well as the original strain, said Dr June Raine, MHRA Chief Executive.

Bivalent vaccines are helping us to meet the challenge of an ever-evolving virus, to help protect people against COVID-19 variants. We have in place a comprehensive safety surveillance strategy for all UK-approved COVID-19 vaccines, and this will include the updated booster we approved today, she said.

This decision has been endorsed by the UK's Commission on Human Medicines and follows the MHRA's approval of the Spikevax bivalent Original/Omicron by Moderna last month.

As with any medicinal product, including vaccines, it is important to continually monitor effectiveness and safety when it is deployed, and we have the relevant processes and expertise in this country to do that, said Professor Sir Munir Pirmohamed, Chair of the Commission on Human Medicines.

The Joint Committee on Vaccination and Immunisation (JCVI) will advise on how this vaccine should be offered as part of the deployment programme, he said.

The MHRA said its decision is based on data from a clinical trial which showed that a booster dose with the bivalent Pfizer/BioNTech vaccine triggers a strong immune response against both Omicron and the original strain.

Safety monitoring showed that the side effects observed were the same as those seen for the original Pfizer/BioNTech booster dose and were typically mild and self-resolving, and no new serious safety concerns were identified.

It comes as the National Health Service (NHS) announced its autumn vaccine booster rollout this weekend, with care home residents and staff set to be among the first in the world to receive the new, variant-tackling jabs from Monday.

Around 4 million people who are at highest risk, including the over 75s and those with weakened immune systems, will also be eligible to book a vaccine through the NHS National Booking Service next week, with the first appointments available from the following week.

Our autumn booster programme kicks off from Monday, with care home residents, staff and the housebound the first to receive their jabs, said UK Health Secretary Steve Barclay.

An autumn booster will top up the immunity of those most vulnerable to COVID ahead of the winter to help us continue to live with this virus without restrictions. Please come forward for your booster and flu vaccine when invited, he said.

As with previous campaigns, the oldest and most vulnerable will be called forward for boosters first.

The precision and speed of the NHS COVID-19 vaccination programme allowed us to get back to a pre-pandemic way of life and doing the things that we love, said NHS Chief Executive Amanda Pritchard.

"While we know that this winter will be challenging with a likely resurgence in both COVID and flu for the first time since before the pandemic, the best way to protect yourselves and your loved ones from serious illness is to get the newly approved, next generation COVID vaccine when invited to do so, as well as your annual flu jab, to ensure you have maximum protection, she said.

Around 26 million people across England will be eligible for an autumn booster over the coming weeks, which includes over 50s, those with a weakened immune system, health and social care workers and care home residents and housebound people, in line with guidance set out by the JCVI.