The UK’s chief medical officers have defended a decision to delay second doses of the Pfizer/BioNTech vaccine in order to prioritize first doses, saying it will protect as many vulnerable people as possible while the coronavirus is running rampant.
The new strategy, announced Wednesday by the head of the UK’s medicines regulator MHRA, means that the interval between doses could be extended to up to 12 weeks, instead of the three weeks previously stipulated.
It has prompted a debate among experts, with the British Medical Association (BMA), a body representing UK doctors, criticizing the move to postpone appointments for the very vulnerable patients currently awaiting their second shots.
The Pfizer/BioNTech vaccine has been in use in the UK since early December, when the country became the first in the world to approve it, but supplies are limited.
The argument over the vaccination strategy comes as infection rates soar in much of the UK, thanks in part to a new, more infectious variant of the virus. Most of England is now under the toughest level of restrictions to try to limit the virus’ spread.
“This group of very elderly patients is at the highest risk of death if they contract Covid-19, which is why GPs are so concerned for them. It is grossly and patently unfair to tens of thousands of our most at-risk patients to now try to reschedule their appointments,” Dr. Richard Vautrey, chair of the BMA General Practitioners Committee, said in a statement Thursday.
The Doctors’ Association UK also raised “real and grave concerns” over the new vaccination strategy, warning Friday that it could undermine the National Health Service’s patient consent process, “as well as completely failing to follow the science.”
Meanwhile, Pfizer said it did not have data to demonstrate that just a single dose of its vaccine would provide protection against the disease after more than 21 days.
“Pfizer and BioNTech’s Phase 3 study for the Covid-19 vaccine was designed to evaluate the vaccine’s safety and efficacy following a 2-dose schedule, separated by 21 days,” Pfizer said in a statement on Thursday. “There are no data to demonstrate that protection after the first dose is sustained after 21 days.”
But the chief medical officers for England, Scotland, Wales and Northern Ireland defended the move in a letter to healthcare professionals published Thursday, saying it was based on the “balance of risks and benefits,” and that the “great majority” of initial protection came from the first jab.
“The second vaccine dose is likely to be very important for duration of protection, and at an appropriate dose interval may further increase vaccine efficacy,” they said.
“In the short term, the additional increase of vaccine efficacy from the second dose is likely to be modest; the great majority of the initial protection from clinical disease is after the first dose of vaccine.”
