GENEVA • People should get two doses of the Pfizer-BioNTech vaccine within 21 to 28 days, the World Health Organisation (WHO) has said, as many countries struggled to administer the jabs that can ward off Covid-19.
Many are experiencing intensifying pressure on their health services due to surging coronavirus cases and the emergence of new variants that appear to spread more easily.
Governments are facing massive demand for vaccines, which are seen as the best way out of the global health crisis.
But with jabs in limited supply, the WHO has been examining how they can be used most effectively.
“We deliberated and came out with the following recommendation: two doses of this (Pfizer) vaccine within 21 to 28 days,” Dr Alejandro Cravioto, chairman of WHO’s Strategic Advisory Group of Experts on Immunisation (Sage), said on Tuesday.
The panel added that countries should have leeway to spread out shots over six weeks so that more people at higher risk of illness can get them.
“Sage made a provision for countries in exceptional circumstances of (Pfizer) vaccine supply constraints to delay the administration of the second dose for a few weeks, in order to maximise the number of individuals benefiting from a first dose,” Dr Cravioto said.
“I think we have to be a bit open to these types of decisions which countries have to make according to their own epidemiological situations.”
More than 86 million people have been reported to be infected with Covid-19 globally, and around 1.87 million have died.
Sage executive secretary Joachim Hombach said spacing out the two Pfizer inoculations could be acceptable for countries unable to implement the main recommendation.
“We… totally acknowledge that countries may see needs to be even more flexible in terms of administration of the second dose. But it is important to note that there is very little… empirical data from the trials that underpin this type of recommendation,” he added.
Five British medical scientists have criticised the British government’s plan to delay giving second doses by up to 12 weeks, saying that proven dosing schedules should not be altered “without solid scientific support or evidence”.
In an opinion piece published in the British Medical Journal (BMJ), the scientists from the universities of Nottingham, Manchester and De Montfort wrote that suggestions by officials on the government’s Joint Committee on Vaccination and Immunisation (JCVI) that the delay strategy was due to shortages of Covid-19 shots were “disputed by vaccine manufacturers”.
“The JCVI advice… to delay the second dose to between four and 12 weeks is not based on data from the trial, but on an assumption of what would have happened if the second dose hadn’t been given at 21 days,” they wrote in the BMJ.
“While assumptions can be useful for generating a hypothesis, alone they are not a sufficient reason to alter a known effective dosing regimen.”
More than one million people in England, or one person in every 50, now have the coronavirus, the British government has said.
Meanwhile, scientists at the National Institutes of Health and Moderna may take about two months to determine whether doses of the company’s Covid-19 vaccine can be halved to double the supply of shots in the United States, according to the agency.
The US has been considering the move to halve doses for Moderna’s vaccine, which requires two injections, to free up supply for more vaccinations.
Sign up for our daily updates here and get the latest news delivered to your inbox.
Get The Straits Times app and receive breaking news alerts and more. Download from the Apple App Store or Google Play Store now.