A leading scientist has said there is no evidence COVID booster jabs will be required amid warnings they could slow down the global vaccine rollout.
Advanced nations across the world including the UK have been planning to introduce booster jabs as soon as this year.
The government has already ordered 60 million doses of the Pfizer vaccine in preparation for a booster campaign.
But some scientists expressed concern that public expectations around COVID-19 boosters are being set by pharmaceutical executives rather than health specialists, and that this could slow down a global rollout as rich nations hoard vaccines even once they've finishing vaccinating their populations.
They agreed that preparing for such a need as a precaution was prudent but this should not come at the expense of reserving more vaccines when they could be used in poorer parts of the world.
They fear a push by wealthy nations for repeat vaccination as early as this year will deepen the divide with poorer countries that are struggling to buy vaccines and may take years to vaccinate their citizens even once.
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"We don't see the data yet that would inform a decision about whether or not booster doses are needed," said Kate O'Brien, director of the Department of Immunization, Vaccines and Biologicals at the World Health Organization (WHO).
O'Brien said the WHO is forming a panel of experts to assess all variant and vaccine efficacy data and recommend changes to vaccination programs as needed.
Dr Tom Frieden, former director of the US Centers for Disease Control and Prevention, said: "There is zero, and I mean zero, evidence to suggest that that is the case."
"It's completely inappropriate to say that we're likely to need an annual booster, because we have no idea what the likelihood of that is."
Pfizer CEO Albert Bourla has said people will "likely" need a booster dose of the company's vaccine every 12 months – similar to an annual flu shot – to maintain high levels of immunity against the original SARS-CoV-2 virus and its variants.
Pfizer has made billions so far from selling the vaccine but is facing the threat of its patent being revoked in order to speed up the production of the vaccine.
AstraZeneca has been selling their jab at zero profit.
The UK has been revealing plans steadily over recent weeks about preparations for booster jabs beginning as soon as this autumn.
Vaccines minister Nadhim Zahawi acknowledged last week "clinicians haven’t yet made the decision when they will need to boost, whether to give more immunity to the most vulnerable, to increase the durability of the protection or to deal with the variant.
“When they decide, I want to give them as much optionality, as many vaccines that were, then they will make those choices.”
The main concern is if potentially vaccine resilient variants beginning spreading through the population.
So far scientists have found most variants of concern can be beaten with the current vaccines, but some, particularly the South African variant, are more worrying.
Vaccine producers are working round the clock to test their jabs against any vaccines and potentially update them to make them more powerful.
Moderna recently announced that a single dose of one of its vaccines given as a booster to previously vaccinated individuals increased neutralising antibody titer responses against COVID and both the South Africa and Brazil variants.
The UK has given over two-thirds of its adult population at least one dose of a COVID vaccine, but several countries, mainly in Africa, have yet to administer a single dose.