The British Medical Association (BMA) has called on health officials and the government to reconsider the gap between doses of the BioNTech-Pfizer coronavirus vaccine.

In a statement emailed to England's chief medical officer, the doctors' group called for officials to "urgently review the UK's current position of second doses after 12 weeks."

The BMA said there was "growing concern from the medical profession regarding the delay of the second dose of the Pfizer-BioNTech vaccine as Britain's strategy has become increasingly isolated from many other countries.''

"BMA members are also concerned that, given the unpredictability of supplies, there may not be any guarantees that second doses of the Pfizer vaccine will be available in 12 weeks' time," the statement added.

The doctors' concerns also comes a day after government medical advisers said early evidence indicates that virus variant B117, which was first discovered in the UK, could be deadlier than the original strain.

The UK currently allows up to 12 weeks between coronavirus vaccine doses, a time frame fits with the vaccine developed by AstraZeneca and Oxford University. The vaccine's producers said they believe the first dose of the jab continues to offer protection after 12 weeks.

But BioNTech and Pfizer say they haven't tested the efficacy of its vaccine after such a long gap and recommend a shorter period between the shots.

The World Health Organization has said the second dose of the BioNTech-Pfizer vaccine could be given after six weeks, but only "in exceptional circumstances."

Why is the UK delaying the second dose?

The British government and health officials are prioritizing first doses of COVID-19 vaccines in a bid to give as many people as possible some initial protection.

Researchers in the UK are also measuring antibodies in the blood of people who have been vaccinated to better understand the best timing for the shots.

Chris Whitty, the British government's chief medical officer, said on Friday that the longer gap was a "public health decision" that was based on a belief that the majority of protection against the coronavirus comes from the first dose of the vaccine.

Yvonne Doyle, medical director of Public Health England, also defended the government's policy, saying it was "a reasonable scientific balance on the basis of both supply and also protecting the most people.''

Nearly 5.5 million people in the UK have received at least one dose of either the BioNTech-Pfizer vaccine or the AstraZeneca/Oxford jab.

France moves to extend gap

France is also considering extending the time between vaccine doses — albeit still a much shorter period than the UK.

France's top health advisory body on Saturday recommended extending the time frame to six weeks instead of the current cap of three weeks.

The Haute Autorite de Sante (HAS) said extending the period between doses would allow the treatment of at least 700,000 more people in the first month.

"The growing number of infections and the worrying arrival of new variants call for an acceleration of the vaccination campaign in order to prevent the epidemic from spiking in coming weeks," the HAS said in a statement.

rs/mm (AP, Reuters)