How frequently should we be updating our COVID-19 vaccines?

Embargoed until: Publicly released: 2023-02-21 03:00

Australia; NSW; VIC

Photo by Mat Napo on Unsplash

The world is trapped in a complicated race between vaccine redevelopment and the continuing mutation of COVID-19 variants, according to Australian and international researchers. Writing in an opinion piece, the researchers outline how the continued spread of COVID-19 allows it to continuously mutate into new variants, meaning we need to be updating our vaccines to broaden our immunity to the ever-changing virus. The researchers discuss the difficulty of appropriately assessing the research quickly enough to adapt vaccines in response to variants, and note bivalent vaccines targeting both the ancestral strain and newer Omicron variants currently only exist among mRNA vaccines despite many other types being in use across the world.

Media release

From: The University of New South Wales

“The current challenge with COVID-19 vaccines is that they were developed based on the first strain of the virus in 2020, which is quite different to what is currently circulating,” says Professor Raina MacIyntre. “Whilst the vaccines continue to protect well against hospitalisation and death, the newer variants ‘escape’ the protection of vaccines more than the original virus did, and so COVID-19 is spreading more easily.”

The TAG-CO-VAC analysed the cross-neutralisation data, which reveals the likely effectiveness of the vaccine against the virus for the existing variants of concern and how effective it will be against ongoing emerging variants. They looked at the data following infection or vaccination in people with varied prior exposure to SARS-COV-2 antigens.

“The TAG-CO-VAC is advising vaccine manufacturers and regulatory authorities to consider updating vaccine antigen composition by including Omicron. Updated vaccines against the Omicron variant are now available as a bivalent booster in Australia,” says Professor Raina MacIntyre. “All adults in Australia can now access the bivalent booster as a 5th dose if they’ve not had a COVID-19 booster or confirmed case in the past six months, and it is strongly recommended for those 65 years and over or adults aged 18-64 years with medical risk factors.”

“Importantly, the primary objective of vaccination is protection against severe disease, and against this objective, the current vaccines continue to perform very well. The bivalent booster, however, can give better protection.”

However the experts caution that this ‘variant-chasing approach’, while effective for now, may not be sustainable in the long-term.

“Given the uncertainties of how the virus will evolve over time, we need to continue exploring other approaches to vaccination. Some intra-nasal vaccines in development are showing promising signs of immune protection. Universal vaccine approaches, like that one currently being explored by the Garvan and Kirby Institutes which target a part of the virus that is less likely to change over time, may be the answer,” says Prof MacIntyre.

Other recommendations included better and country-specific data collection and the importance of testing and genetic surveillance.

Attachments

Note: Not all attachments are visible to the general public. Research URLs will go live after the embargo ends.

Research Springer Nature, Web page The URL will go live after the embargo ends

Journal/
conference: Nature Medicine

Research:Paper

Organisation/s: Kirby Institute, UNSW Sydney, The University of New South Wales, The Peter Doherty Institute for Infection and Immunity, The University of Melbourne, World Health Organization (WHO)

Funder: None reported

Media Contact/s

Contact details are only visible to registered journalists.