Britain has decided to go in for a third booster vaccine shot for all those above 50 years of age, vulnerable people and frontline health staff.

The decision is expected to trigger a rethink on the subject in other countries as well.

Israel is already going ahead with plans for giving booster shots to older adults in order to enhance their protection against COVID-19 and a number of other advanced countries are also considering a similar strategy to combat the pandemic.

But the WHO as well as other global-health researchers warn that this strategy could weaken the global fight to defeat the pandemic as the vaccines being allocated for booster shots should go instead to poor countries where less than 2% of the population has been vaccinated.

Britain’s Joint Committee on Vaccination and Immunisation on Tuesday recommended a third dose six months after a second shot, paving the way for a broad revaccination programme in Britain, which has one of the world's highest death tolls from COVID-19.

Its recommendation comes after some leading scientists, including from the U.S. Food and Drug Administration and World Health Organisation, said in an article in the Lancet medical journal on Monday that COVID boosters were not yet needed for the general population.

"Our latest estimates are that since we began deploying these vaccines, they've probably averted in the region of 24 million cases of COVID in the UK and 112,000 deaths – so incredibly successful to date and remains so," England's Deputy Chief Medical Officer Jonathan Van-Tam told journalists.

"We're not past the pandemic. We know this winter could quite possibly be bumpy at times."

"The pandemic is far from over, but thanks to our phenomenal vaccine programme, new treatments and testing we are able to live with the virus without significant restrictions on our freedoms," Prime Minister Boris Johnson said in a statement.

Britain has officially recorded 134,000 COVID-19 deaths, and more than 7 million cases. So far 44 million people have had two vaccine doses, 81 percent of those aged over 16. On Monday, the government said those aged 12 to 15 would also be offered shots.

 It said its preference was that the Pfizer vaccine was used for the booster dose, or alternatively a half-dose of a Moderna shot.

Professor Lim Wei Shen, chair for COVID-19 immunisation on the JCVI, said their advice for a booster dose did not imply that there would be a requirement for a shot every six months.

He also said not everyone under 50 years old would require another shot.

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