UK Approves Single Doses of COVID-19 Vaccine Despite Lack of Evidence

Why is the United Kingdom going to administer single vaccine doses to a wider body of people, rather than withhold additional doses so people receive their second dose — a controversial move that's receiving criticism from the FDA?

UK officials are allowing single doses of COVID-19 vaccines. SOPA Images/Getty Images
  • In the United Kingdom, a lack of COVID-19 vaccine doses has led health officials to announce that they will be distributing the vaccine in single doses to reach a wider section of the population.
  • The Food and Drug Administration has warned against this type of vaccine plan.
  • We talked to experts about what they advise.

The COVID-19 vaccine is here and will likely help stop the spread of the novel coronavirus.

But there’s a big problem: There aren’t enough vaccine doses to go around.

The lack doses is causing controversy in how it’s distributed both here and abroad.

In the United States, the Food and Drug Administration (FDA) has currently approved two versions of the vaccine: the Pfizer-BioNTech vaccine and the Moderna vaccine. They’re being distributed in tier groups based on greatest need.

Both require two doses for maximum effectiveness.

In the United Kingdom, a lack of vaccine doses has led health officials to announce that they will be distributing the vaccine in single doses to reach a wider section of the population.

But experts warn this way of vaccinating the public hasn’t been fully tested.

So, why is the United Kingdom going to administer single doses to a wider body of people, rather than withhold additional doses so people receive their second dose — a controversial move that’s receiving criticism from the FDA?

And what does this mean for immunity in the immediate future?

Why is the U.K. administering single doses?

Recently, the FDA released a statement urging people who get the vaccine to stick to the authorized dosing schedules.

The two different mRNA vaccines that have been approved show an effectiveness of about 95 percent, but only after people have received both doses.

But surging COVID-19 cases have put pressure on U.S. and U.K. health officials to take action, whether that action is backed by science or not.

According to the U.K. Joint Committee on Vaccination and Immunization (JCVI), “Given the high level of protection afforded by the first dose, models suggest that initially vaccinating a greater number of people with a single dose will prevent more deaths and hospitalizations than vaccinating a smaller number of people with two doses.”

There are currently two versions of the vaccine being administered in the United Kingdom: the Pfizer-BioNTech vaccine and the AstraZeneca vaccine.

The AstraZeneca vaccine hasn’t been approved yet by the FDA in the United States.

JCVI reports that short-term vaccine effectiveness from the Pfizer-BioNTech vaccine is calculated at around 90 percent, though that’s not confirmed in the United States.

AstraZeneca’s first dose is showing 70 percent effectiveness.

The second dose, JCVI says, is still important for longer lasting protection.

Why is this considered controversial?

It’s controversial for a few reasons.

First, administering only a single dose of the COVID-19 vaccine wasn’t the way the clinical trials were conducted, so it’s not clear what the expected outcomes will be.

The trials for both Pfizer-BioNTech and Moderna were conducted with two doses, which has been proven to be highly effective.

There’s not enough data to know how effective a single dose would be, but it would be considerably less effective.

“We don’t have the confirmed efficacy of one dose. That needs to be studied a bit more,” said Dr. Matthew Heinz, a hospitalist in Tucson, Arizona. “If you have one dose versus zero doses, one is better. But that is still suboptimal.”

“If many people are only getting one shot [of the vaccine], they will not have that 95 percent protection. We don’t have a complete understanding of what a single shot does when currently a booster shot is recommended,” Heinz added.

For many health experts, the goal of vaccination is to reach “herd immunity.” To achieve herd immunity, 80 to 85 percent of the population has to be vaccinated to stop the virus from spreading widely.

Other concerns include that those who are only receiving one dose can still contract an infection, display symptoms, and be contagious, further spreading the virus.

However, Heinz noted, with a single dose administered, an infection may not be a 10- or 14-day ordeal.

People with a single dose would likely not get the full brunt of COVID-19.

“A good analogy is our flu shot,” he said. “They are rarely perfect. Scientists and public health officials take a stab at what is going to be most common for the upcoming winter. Therefore, the efficacy is 15, 20, and 30 percent, but you still do get some protection. You may still get a flu, but it won’t be as severe or last as long.”

A valid option?

Other experts, however, see the United Kingdom’s decision as simply another alternative.

“There are many roads to Rome,” said Dr. William Schaffner, a Vanderbilt University professor of preventive medicine, health policy, in the division of infectious diseases. “These are two different strategies, and each has its advantages and disadvantages.”

“The first dose does indeed provide some partial protection,” he said. “That’s not the way it was authorized to be used, but it is a public health strategy. The advantage is that you give some degree of protection to the maximum number of people.”

The disadvantage, however, is that many of those people who receive their first dose will think that they’re completely immune and will begin to relax other safety measures, like mask wearing and physical distancing.

They may inappropriately expose themselves to risk.

“That is unfortunate,” Schaffner said. “The other thing is that the vaccine hasn’t been studied at longer intervals between doses. But with every other vaccine we’ve dealt with, longer intervals don’t matter very much.”

“We shouldn’t make too much of it,” he noted. “It’s a matter of reasonable people making reasonable decisions, and there is no single right decision.”

Why has the rollout gone so slowly?

With the controversy brewing, it’s logical to ask, What’s the holdup? Why can’t we just make more of the vaccine and solve this problem?

The answer is simply scarcity of resources.

According to The New York Times, the reasons for the slow rollout are unclear, only that the task of distributing thousands of vaccine doses is a big undertaking — especially with so many health departments already spread too thin because of the effects of the pandemic.

“We want to do this as fast as possible, but also as safely as possible,” Heinz said.

“We, of course, want to do what we can to make the limited supply work for more people, and last longer for our health departments. But we don’t want to sacrifice too much in the way of effectiveness. There has to be a balance,” he said.

Heinz noted that the overarching theme right now is that we’re in a time of scarcity, but there will be a time when there’s widespread availability for the public.

When we’re in that time frame, hopefully with additional approved vaccines by Johnson & Johnson and AstraZeneca, who and how to distribute won’t be as much of a Sophie’s choice.

This story originally appeared on: Healthline.com - Author:Meagan Drillinger