The World Health Organization (WHO) has recommended that both doses of Pfizer/BioNTech’s should be given within 21-28 days, echoing the US Food and Drug Administration’s (FDA) recently announced recommendations.
The WHO’s Strategic Advisory Group of Experts on Immunization (SAGE) added, however, that countries should be able to administer the two doses over six weeks to ensure more high-priority groups can access the vaccine.
“We deliberated and came out with the following recommendation: two doses of [the Pfizer/BioNTech] vaccine within 21-28 days,” said Alejandro Cravioto, chairman of the WHO’s Strategic Advisory Group of Experts on Immunization (SAGE).
“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,” he added.
The FDA released a statement earlier this week that it will not make any changes to dosing or schedules for authorised COVID-19 vaccines, which includes both Pfizer/BioNTech and Moderna’s vaccines, which both have emergency use authorisations (EUA).
For the Pfizer/BioNTech vaccine, the recommended interval between the first and second dose is 21 days, while the two doses of the Moderna vaccine are recommended to be given 28 days apart.
The US health agency argued that the available data only supports using the two specified doses of the authorised vaccines at the specified intervals.
“We know that some of these discussions about changing the dosing schedule or dose are based on a belief that changing the dose or dosing schedule can help get more vaccine to the public faster,” commented the FDA.
“However, making such changes that are not supported by adequate scientific evidence may ultimately be counterproductive to public health,” the agency added.
In the UK, however, health authorities have decided that they will increase the time period between vaccine doses to up to 12 weeks, in a move aimed at protecting a larger proportion of people from COVID-19.
The UK’s four chief medical officers said in a statement that they were ‘confident that based on publicly available data as well as data available to the Joint Committee on Vaccination and Immunisation (JCVI) that the first dose of either [the] Pfizer or AstraZeneca vaccine provides substantial protection within 2-3 weeks of vaccination for clinical disease, and in particular severe COVID disease’.
The WHO’s Cravioto added: “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.”