Britain has become the first country in the world to approve a “next generation” Covid-19 vaccine that targets both the original and Omicron variants.
The UK medicines regulator, the MHRA, approved the bivalent vaccine made by US drug company Moderna as a booster for adults.
The agency's decision was based on clinical trial data that showed the booster triggered “a strong immune response” against both Omicron (BA.1) and the original 2020 virus, it said.
The MHRA also cited an exploratory analysis in which the shot was also found to generate a good immune response against the currently dominant Omicron offshoots BA.4 and BA.5.
Such an approach is used with flu shots, which are adjusted each year depending on the variants that are circulating and can protect against four influenza strains.
MHRA chief executive Dr June Raine said the new vaccine give "a sharpened tool in our armoury to help protect us against this disease as the virus continues to evolve".
The development came as it was announced that Pfizer chief executive Albert Bourla has tested positive for Covid-19 and is receiving Paxlovid, the treatment made by his company. He is experiencing very mild symptoms, a company statement said.
Britain was the first country to approve a coronavirus vaccine in late 2020.
Developers of some of the world’s most widely used Covid shots, from Pfizer and Moderna to China’s Sinovac Biotech have all started developing new shots targeting Omicron.
According to the World Health Organisation, the latest global surge of Covid-19 has been driven by omicron subvariant BA.5, which is responsible about 70 per cent of the virus samples shared with the world’s largest public virus database. The subvariant BA.5 is even more infectious than the original version of omicron and has some genetic differences that earlier vaccines might not address.
Moderna's chief medical officer Dr Paul Burton previously said that its vaccine could boost a person's antibodies to such high levels that it may only be needed annually.
In June the, company said trial data showed that when given as a fourth dose, the variant-adapted shot raised virus-neutralising antibodies by eight-fold against Omicron.
Stephane Bancel, Moderna's chief executive, described it as a “next generation Covid-19 vaccine” that will play an “important role in protecting people in the UK from Covid-19" in winter.
Mr Bancel said: “This bivalent vaccine has an important role to play in protecting people in the UK from Covid-19 as we enter the winter months.”
Mr Bancel said the drug had “consistently shown superior breadth of immune response” over alternatives in clinical trials.
Now approval has been secured, the UK's Joint Committee on Vaccination and Immunisation (JCVI) will advise on how the vaccine should be used in the country.
The UK government said last month a vaccine booster programme would begin in "early autumn" and that shots would offered to over 50s, individuals in clinical risk groups, frontline workers and care homes staff.
While existing Covid-19 vaccines continue to provide good protection against hospital admission and death, vaccine effectiveness has taken a hit as the virus has evolved.
The MHRA said the side effects were the same as those in the original Moderna booster dose and were typically mild.
Prof Sir Munir Pirmohamed, chairman of the commission on human medicines, an independent body sponsored by the DHSC to advise ministers on the safety, efficacy and quality of medicinal products, said the vaccine was safe to use.
He said: “The Commission on Human Medicines and its Covid-19 Vaccines Expert Working Group has independently reviewed the data on safety, quality and effectiveness and agrees with the MHRA's decision.”
He said that since the coronavirus was “continually evolving in order to evade the immunity provided by vaccines”, constant updates to the drugs were needed.
Scientists have warned that the continued genetic evolution of Covid-19 means drugmakers will likely be one step behind the virus in their efforts to tailor their vaccines.
“The virus is unlikely to stand still and Omicron-targeted immunity, might push the virus down other evolutionary paths,” warned Jonathan Ball, a professor of virology at Britain’s University of Nottingham. Still, he said the new Moderna vaccine would likely still be protective.
“Unless there is a major shift in the virus, immunity will continue to protect the vast majority from serious disease caused by emerging variants,” he said in a statement.
Prof Pirmohamed said a recent paper in medical journal The Lancet suggested that coronavirus vaccines prevented up to 20 million deaths in their first year of use.
Moderna said it had also completed its applications for regulatory approval of the booster in Australia, Canada and the EU.
European Medicines Agency (EMA) officials expect Covid variant-adapted vaccines to be approved in September, and have signalled the regulator is open to using shots targeting the older BA.1 variant this autumn, given those specifically targeting newer subvariants are further behind in clinical development.
In contrast, the US Food and Drug Administration has said it would seek the specific inclusion of the newer BA.4 and BA.5 offshoots of Omicron in any new shots used domestically.
Known as mRNA-1273.214, the dose is an updated version of the Moderna vaccine which is already in use for first, second and booster doses.
Pfizer Inc and BioNTech have also been testing versions of their mRNA vaccine, modified to combat Omicron variants.
Sanofi and its partner GSK are working on a protein-based vaccine that targets the Beta subvariant, which dominated for some time last year.