FDA pushes back on ‘premature’ Operation Warp Speed suggestion of halving Covid vaccine dosages

Pfizer and Moderna coronavirus vaccines require two full doses spaced 21 days apart

The Food and Drug Administration (FDA) has addressed suggestions made by Operation Warp Speed advisers that the coronavirus vaccine dosage could be halved so more people could receive the jab faster.

Moncef Slaoui, the chief science adviser for Operation Warp Speed, claimed there was evidence that giving people aged 18 to 55 two half-doses would give them an “identical immune response” compared to the current dosage when speaking CBS’s Face the Nation on Sunday.

But this suggestion was rebutted by FDA Commissioner Stephen Hahn and Peter Marks, director of the agency’s Center for Biologics Evaluation and Research, in a statement released on Monday.

The agency said it was following the conversations about the potential of giving adults a half-dose of the vaccine, but that practice would not be recommended given current data.

“These are all reasonable questions to consider and evaluate in clinical trials. However, at this time, suggesting changes to the FDA-authorized dosing or schedules of these vaccines is premature and not rooted solidly in the available evidence,” the statement read.

“Without appropriate data supporting such changes in vaccine administration, we run a significant risk of placing public health at risk, undermining the historic vaccination efforts to protect the population from Covid-19.”

Two coronavirus vaccines have received emergency use authorisation from the FDA: Moderna and Pfizer. This emergency use authorisation requires those who receive the vaccine to get two separate doses spaced 21 days apart.

These vaccines provide 95 per cent efficacy against Covid-19 after the second dose, based on data from the final phase of human trials. 

“We have committed time and time again to make decisions based on data and science. Until vaccine manufacturers have data and science supporting a change, we continue to strongly recommend that health care providers follow the FDA-authorised dosing schedule for each Covid-19 vaccine,” the FDA’s statement read. 

Due to the limited doses currently available, states have prioritised healthcare workers and those living in long-term care facilities to first receive the vaccine.

Initially it was anticipated for 20 million Americans to receive the vaccine by the end of 2020, but the country fell short of that expectation and has vaccinated more than 4.5 million people as of Monday morning, according to the Centers for Disease Control and Prevention (CDC) vaccine tracker.

More than 15.4 million doses have been distributed to states.

Why it was taking longer for the federal government to send doses and for states to then administer the doses than originally anticipated remains unclear.

Both Florida and New York’s governors have put pressure on hospitals to administer the doses faster. Some states have also opened up vaccination centres for people ages 65 and older to get the vaccine into the arms of the general public.