“This week, the U.K. decided to delay second doses in order to prioritize getting the first doses to more people.
The U.K. decision has restarted conversations about whether the U.S. and Florida should do the same…
Pfizer’s two vaccines are given 21 days apart, and Moderna’s can be given 28 days apart.
Early vaccine trial results show a 50% to 60% efficacy after participants took the first vaccine.
The Food and Drug Administration’s emergency authorization was based on the efficacy and immunity of two doses.
Doctors say only one dose will leave people only partially protected and will leave the virus diminished but still spreading.
In the beginning, Pfizer was only sending that second shot as it was needed, but as millions and millions of doses are delivered in future months, it could be up to states to determine whether they want to follow the U.K.’s decision.” (A)
“In a shift from practices in the US, Britain plans to give people second doses of the coronavirus vaccines within 12 weeks of their first shot rather than within 21 days, to accelerate immunizations across as many people as quickly as possible. The practice has drawn some criticism from experts around the world…
More than a million people in the UK have already received their first jab of the Pfizer vaccine. Earlier this week, Britain also approved a vaccine developed by the University of Oxford and British pharmaceutical firm AstraZeneca that is substantially cheaper and easier to use.
British authorities then outlined the new dosing regimen, which delays a person’s second vaccine shot from being done at three weeks to being given up to 12 weeks after the first shot. According to The New York Times, British health authorities were also given permission to combine the vaccines, should a second dose by one of the companies not be available.
“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,” British medical officers said.
The UK plans to ramp up vaccinations on Monday using 530,000 doses of the AstraZeneca vaccine and has set a goal of vaccinating 2 million people a week as soon as possible.
Still, the new plan has faced criticism. The UK’s main union for doctors warned that delaying the second dose causes huge scheduling problems for thousands of partially vaccinated elderly and vulnerable people.
“It is grossly and patently unfair to tens of thousands of our most at-risk patients to now try to reschedule their appointments,” said Richard Vautrey from the British Medical Association.
Responding to the intention to mix the vaccines — a practice banned by the CDC, — John Moore, a vaccine expert at Cornell University, told The New York Times that British officials “seem to have abandoned science completely now and are just trying to guess their way out of a mess.” (B)
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…
“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….
Pfizer said it had not evaluated different dosing schedules because “the majority of trial participants received the second dose within the window specified in the study design.”
In its open letter, the Doctors’ Association UK wrote: “Protection provided by the first dose of the Pfizer vaccine is considerably lower at 52.4% compared to 95% if two doses given three weeks apart.”
Vautrey told CNN that greater assurances would be needed from both the UK chief medical officers and Pfizer in order to give healthcare professionals and patients confidence in the government’s strategy.
“We need Pfizer themselves to be confident that this new dosage regime is going to deliver effective coverage and protection to our patients, particularly our most vulnerable patients,” Vautrey said.” (C)
“As governments around the world rush to vaccinate their citizens, scientists and policymakers are locked in a heated debate over a surprising question: Is it wisest to hold back the second doses everyone will need, or to give as many people as possible an inoculation now — and push back the second doses?…
The vaccines authorized so far in the United States are produced by Pfizer-BioNTech and Moderna. Britain has greenlit the Pfizer-BioNTech and Oxford-AstraZeneca vaccines.
All of them are intended to be delivered in two doses on a strict schedule. The first injection teaches the immune system to recognize a new pathogen by showing it a harmless version of some of the virus’s most salient features. After the body has had time to study up on this material, as it were, a second shot presents these features again, helping immune cells commit the lesson to memory.
Clinical trials run by Pfizer-BioNTech and Moderna showed the vaccines were highly effective at preventing cases of Covid-19 when delivered in two doses separated by three or four weeks.
Some protection appears to kick in after the first shot of vaccine, although it’s unclear how quickly it may wane. Still, some experts now argue that spreading vaccines more thinly across a population by concentrating on first doses may save more lives than making sure half as many individuals receive both doses on schedule.
That would be a remarkable departure from the original plan. Since the rollout began last month in the United States, second shots of the vaccines have been held back to guarantee that they will be available for people who have gotten their first injections…
But some researchers fear the delayed-dose approach could prove disastrous, particularly in the United States, where rollouts are already stymied by logistical hurdles and a patchwork approach to prioritizing who gets the first vaccinations.
“We have an issue with distribution, not the number of doses,” said Saad Omer, a vaccine expert at Yale University. “Doubling the number of doses doesn’t double your capacity to give doses.” (D)
“Dr. Anthony S. Fauci, the nation’s top infectious disease expert, told CNN on Friday that the United States would not follow Britain’s lead in front-loading first vaccine injections, potentially delaying the administration of second doses….
“I would not be in favor of that,” Dr. Fauci told CNN’s Elizabeth Cohen, regarding altering dosing schedules for the vaccines authorized for use in the United States, made by Pfizer and Moderna. “We’re going to keep doing what we’re doing.”
His opinion was met with approval by some experts, including Dr. Eric Topol, a clinical trials expert at the Scripps Research Translational Institute in California, who tweeted, “That’s good because that it’s following what we know, the trial data with extraordinary 95 percent efficacy, avoiding extrapolation and the unknowns.”…
Straying from this regimen “is like going into the Wild West,” said Dr. Phyllis Tien, an infectious disease physician at the University of California, San Francisco. “It needs to be data driven if they’re going to make a change.”
Widening the gap between vaccine doses could risk blunting the benefits of the second shot, which is intended to boost the body’s defenses against the coronavirus, increasing the strength and durability of the immune response. In the interim, the protective effects of the first shot could also wane faster than anticipated.
With Pfizer’s vaccine, for example, “we don’t really know what happens when you only have one dose after, like, a month,” said Natalie Dean, a biostatistician at the University of Florida. “It’s just not the way it was tested.” (E)
- A.Doctors detail issues from delayed second dose of COVID-19 vaccines, By Deanna Allbrittin and James Tutten, https://www.wftv.com/news/local/doctors-detail-issues-delayed-second-dose-covid-19-vaccines/BT5SJOCADFAJXEJAEW5D23ZKXI/
- B.Experts criticize British policy, which also reportedly includes directive allowing healthcare workers to mix Pfizer-BioNTech and AstraZeneca inoculations, https://www.timesofisrael.com/an-act-of-desperation-uks-delay-of-second-vaccine-dose-comes-under-fire/
- C.UK chief medical officers defend delay of second Pfizer Covid-19 vaccine doses, By Laura Smith-Spark and Nada Bashir, https://www.cnn.com/2021/01/01/health/uk-vaccine-doses-chief-medical-officers-intl/index.html
- D.Covid-19 Live Updates: Scientists Debate Holding Back Second Vaccine Dose, by Katherine J. Wu and Rebecca Robbins, https://www.nytimes.com/live/2021/01/04/world/covid-19-coronavirus
- E.Dr. Fauci advises against the British approach of delaying a second dose of vaccine., By Katherine J. Wu, https://www.nytimes.com/2021/01/01/world/dr-fauci-advises-against-the-british-approach-of-delaying-a-second-dose-of-vaccine.html?referringSource=articleShare