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Newly Authorised Bivalent COVID-19 Booster Offers Omicron Protection

Editor's note: This article was updated with additional information from the JCVI advice.

A 'next generation' bivalent COVID-19 vaccine that targets two variants of the SARS-CoV-2 virus will be deployed in this year's autumn booster programme after it was granted conditional authorisation by UK regulators.

The mRNA vaccine 1273.214 (Spikevax Bivalent, Moderna) contains the original vaccine used during the pandemic, plus a vaccine candidate targeting the Omicron variant in a 50/50 split.

The vaccine was approved as a booster for adults aged 18 and over after it met standards of safety, quality and effectiveness, the Medicines and Healthcare products Regulatory Agency (MHRA) said.

Moderna's Spikevax Bivalent vaccine featured on the autumn booster list when the Joint Committee on Vaccination and Immunisation (JCVI) published its advice on which vaccines should be used.

A Strong Antibody Response

The MHRA said its decision was based on phase 2/3 clinical trial data which showed that a booster dose of the updated Moderna vaccine triggered a "strong immune response" against the original 2020 strain of the virus and the BA.1 Omicron variant. The manufacturer claimed Spikevax Bivalent also "elicited potent neutralising antibody responses" against the more transmissible Omicron subvariants, BA.4 and BA.5, compared with its currently authorised booster.

Dr June Raine, MHRA chief executive said the updated vaccine would provide "a sharpened tool in our armoury to help protect us against this disease as the virus continues to evolve".

No serious safety concerns were identified in the trial, the MHRA said, and that side-effects were similar to those seen for the original Moderna booster dose and were typically mild and self-resolving.

The Commission on Human Medicines and its COVID-19 Vaccines Expert Working Group independently reviewed the data on safety, quality, and effectiveness, and agreed with the decision to authorise Spikevax Bivalent. Commission chair, Prof Sir Munir Pirmohamed, said: "The virus, SARS-CoV-2, is continually evolving in order to evade the immunity provided by vaccines. This novel bivalent vaccine represents the next step in the development of vaccines to combat the virus, with its ability to lead to a broader immune response than the original vaccine."

The Joint Committee on Vaccination and Immunisation will now need to advise on whether the vaccine should be offered as part of the deployment programme.

JCVI Advice

The JCVI said it would consider further bivalent vaccines for use in the autumn programme as they were approved by the MHRA. It stated that "where feasible, it would be preferable for a single type of booster vaccine to be offered throughout the duration of the autumn programme for simplicity of deployment".

Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, said that the similarity of the vaccine's new component to the original version, "has allowed the MHRA to authorise the vaccine based on its antibody response rather than demonstrating it prevents infections". But he told the Science Media Centre: "We now know from many studies that this antibody response (neutralising antibodies) is to a degree predictive of the clinical effect in prevention of infection and hence admission to hospital or death.

"It would take very much larger trials to show such effects conclusively, but we can be confident it is likely to show better clinical efficacy against the Omicron variants than the original vaccine alone."

Jonathan Ball, professor of molecular virology at the University of Nottingham, pointed out that Omicron-targeted immunity "might push the virus down other evolutionary paths, in which case we will be like the Red Queen in Alice and the Looking Glass – having to keep running just to stay in the same place". However, "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 added.

Autumn Programme COVID Vaccines

The JCVI advice for COVID booster vaccines are:

For adults aged 18 years and above:

  • Moderna mRNA (Spikevax) bivalent Omicron BA.1/original 'wild-type' vaccine
  • Moderna mRNA (Spikevax) original 'wild-type' vaccine
  • Pfizer-BioNTech mRNA (Comirnaty) original 'wild-type' vaccine
  • In exceptional circumstances, the Novavax Matrix-M adjuvanted' wild-type' vaccine (Nuvaxovid) may be used when no alternative clinically suitable UK-approved COVID-19 vaccine is available

For people aged 12-17 years:

  • Pfizer-BioNTech mRNA (Comirnaty) original 'wild-type' vaccine

For children aged 5-11 years:

  • Pfizer-BioNTech mRNA (Comirnaty) original 'wild-type' vaccine paediatric formulation

Prof Wei Shen Lim, chair of COVID-19 immunisation on the JCVI, said: "It is important that everyone who is eligible takes up a booster this autumn, whichever vaccine is on offer. This will increase your protection against being severely ill from COVID-19 as we move into winter."

Lead Image Credit: iStock/Getty Images