correction

An earlier version of this piece incorrectly stated that President Trump promised the United States would vaccinate 100 million people by the end of 2020. He said they would distribute 100 million vaccine doses by the end of 2020. This version has been updated.

President-elect Joe Biden’s team suggested on Friday that, when the new administration takes office, it intends to release every available dose of the coronavirus vaccine. Biden, a spokesman said, “believes the government should stop holding back vaccine supply so we can get more shots in Americans’ arms now.” This is a 180-degree reversal from the Trump administration’s strategy of keeping enough vaccines in reserve so that everyone who receives the first dose is guaranteed a second.

Although the Biden team’s urgency is well-intentioned, such a change could create more problems than it solves.

Let’s start with the facts on the ground. With coronavirus deaths surpassing 4,000 a day and hospitals overwhelmed in many parts of the country, it makes good sense to vaccinate as many people as quickly as possible. Let’s remember, too, that we’re already behind: Despite President Trump’s promises that the United States would distribute 100 million vaccine doses by the end of 2020, only 6.7 million people have received the vaccine to date.

Where is the bottleneck? The United States lacks a clear and coordinated vaccine strategy. Since the vaccines first became available four weeks ago, more than 22 million doses have been sent to the states. Less than a third of these have actually been given, mostly to health-care workers and nursing home residents.

Hospitals have been left to fend for themselves as they struggled to inoculate workers amid record numbers of coronavirus patients. Because of a lack of funding, local and state health departments are months behind where they should be with recruiting vaccinators and setting up mass vaccination sites.

As a result, the United States is failing at getting vaccines into arms. What worries me now is that if the Biden team rushes more vaccine to states, there is no guarantee those doses will find their way into more arms.

Nor am I convinced that it makes sense to get as many first doses into people unless there is a guarantee of a timely second dose. The second dose of the Pfizer and Moderna vaccines is supposed to be given three or four weeks after the first. These vaccines have been shown to be safe and around 95 percent efficacious when this primer-booster protocol is followed.

But we have no idea what happens if there is an unexpected delay of weeks or months between shots. Will the vaccine be less effective, and if so, by how much? If there is a long enough delay, will the entire vaccine series need to start over, in which case the first dose was essentially wasted? We just don’t know.

Some experts have put forth a proposal of deliberately delaying the second dose to vaccinate more people with the first. This approach deeply troubles me: Already, many people have doubts about the coronavirus vaccine based on the perception that Operation Warp Speed was rushed. I have reassured patients that no shortcuts were taken in vaccine development or approval, and that policymakers have adhered to the science every step of the way. If we were to suddenly change course and adopt policies that deviate from clinical trials, my patients and the public would feel — rightfully — that they were misled. This would further fuel vaccine hesitancy and erode trust in public health.

There is also an ethical consideration. Those who chose to get the first dose had the reasonable expectation that they’d receive the second in a certain time frame. Is it ethical to now withhold the second shot from them, given that they never consented to a revised protocol that has an unproven and unknown efficacy?

To be fair, the Biden team has not said that it intends to hold back the second dose to give more people the first. However, a policy to release all available doses could end up having that effect if the promised supply of the second dose doesn’t come through or if the speed of vaccine administration cannot keep up.

Perhaps the Biden team is confident of vaccine supply. Biden has already committed to invoking the Defense Production Act, which will help prevent raw ingredients that go into vaccines from running out. But mass-producing vaccines can hit other snags. During the H1N1 influenza pandemic, production fell far behind schedule, with some manufacturers producing only a fifth of the vaccines that they had promised. Also, even if production keeps pace, it still does not solve the backlog in vaccine administration, which could hit further roadblocks with increased supply.

I applaud the Biden administration’s clear commitment to speeding up vaccination, but there are other steps officials should take before releasing every available dose. They must have guarantees of production so there will always be enough second doses for all first doses given. They must expedite the “last mile” between getting the vaccine to distribution sites and injecting it into people’s arms. Otherwise, a policy that has the admirable goal of expediting vaccination could worsen mistrust and hinder progress at a time when we can least afford it.

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