Health · August 6, 2022

Officials are wrestling with whether to allow a new monkeypox vaccination strategy

WASHINGTON — It sounded like a simple solution to the monkeypox vaccine shortage: Just by changing how doses are injected, the federal government could vaccinate five times as many people with the existing supply.

But the approach — injecting a fifth of the current dose into the skin rather than a full dose into the underlying fat — isn’t all that simple, experts say. And some federal officials are concerned about changing the method without further research, although Dr. Robert M. Califf, the head of the Food and Drug Administration, called the proposal promising on Thursday.

Some external experts also urge caution. “From a basic science perspective, this should work,” said Dr. Jay K. Varma, the director of the Cornell Center for Pandemic Prevention and Response. “But of course there are many things in life, in science, that we think should work, and then when we actually do them, they don’t.”

Stretching doses of the Jynneos vaccine could help the federal government solve a partially self-inflicted predicament. Despite investing more than $1 billion to develop the two-dose vaccine, which can be used against both monkeypox and smallpox, the government only has 1.1 million shots on hand, partly because they’ve been slow to produce Ordered bulk supplies of vaccine for vial processing.

That supply is enough to feed 550,000 people, but about three times that many doses are needed to feed the 1.6 to 1.7 million Americans who are at high risk for monkeypox, according to the Centers for Disease Control and Prevention are exposed. According to the CDC, for now, the virus is spreading primarily through skin-to-skin contact during sex among gay and bisexual men.

Some federal officials are hoping that by injecting a smaller dose of the vaccine between layers of skin, called intradermal injection, the Biden administration could contain the outbreak before it spreads further.

However, some experts argue that this approach has not been studied enough. They also warn that some vaccinators need training to properly administer the shots, which could slow vaccination efforts. Otherwise, the government could end up wasting cans and not salvaging them.

With intradermal injection, a needle is gently inserted into layers of skin, a thin space containing immune cells. If a vaccinator goes too deep and introduces the dose in fat, the patient may not get enough vaccine, experts say. However, if the needle is not inserted far enough, some of the vaccine may leak out.

“If you’re giving a lower dose and you’re not injecting it properly into the skin — you could be injecting it in the wrong place — you might not be giving a protective vaccine,” said Dr, who was the FDA’s chief vaccine regulator for the past year and worked on the approval of Jynneos by the authority. “When you’re asking for this in millions of doses nationwide, it’s a lot easier to make mistakes in administering the vaccine.”

On the other hand, the method has proven itself. It has been used in polio vaccination campaigns when doses were limited, and in rabies and tuberculosis skin tests.

“It’s not a brand new concept,” said Dr. Anthony S. Fauci, President Biden’s chief medical adviser. “We considered this years ago as a strategy in the event of a vaccine shortage.”

In smallpox vaccination campaigns, vaccinators have used special bifurcated needles that have allowed them to make intradermal injections more consistently and cheaply.

dr John Beigel, an associate director of clinical research at the National Institutes of Health, said a government-sponsored study by Jynneos published in 2015 compared the intradermal approach to the standard injection method and found that they provided a comparable amount of neutralizing agents triggered antibodies. a measure of the strength of the immune response. The intradermal method caused more redness, swelling, and itching, but the standard injection was more painful.

dr Beigel said switching to the intradermal method is a better option for preserving the vaccine than just giving it a single injection, as some jurisdictions are now doing, because research has shown that one injection doesn’t elicit nearly as strong an immune response.

“One dose is probably not effective,” he said, adding that the intradermal method “is an acceptable route.”

Although the 2015 study had hundreds of participants, some experts note that it was a single study with limited readings. NIH researchers had planned to test the intradermal strategy for Jynneos in a study that should start in a few weeks. But results weren’t expected until late fall or early winter, and that plan is up in the air for now.

dr H. Clifford Lane, the clinical director of the National Institute of Allergy and Infectious Diseases by Dr. Fauci at the NIH, said that while researchers could gain insight by tracking people who get vaccinated, a traditional clinical trial would provide a clearer picture.

“I can understand it as long as it’s very clear why it’s being done,” he said of the intradermal strategy. “The question is: how can we expand current stockpiles without significantly compromising effectiveness?”

Another question is how well the vaccine will actually work: It was approved for use against both monkeypox and smallpox in 2019 after studies showed it elicited a stronger immune response than a previous vaccine. This drug itself was approved because it compared favorably to an even earlier vaccine, federal officials said.

Monkeypox is rarely fatal and no fatalities have been reported in the United States. Symptoms usually subside within two to four weeks. But as the outbreak surged from eight reported cases in late May to 7,510 now, the administration is scrambling to improve vaccination coverage and the availability of tests and treatments.

As of now, the outbreak is almost exclusively confined to men who have sex with men, with those who have multiple partners considered to be particularly at risk. So far, however, five cases involving children have been reported. On Friday, the Illinois Department of Health announced that an adult who works at a daycare center has tested positive for monkeypox and that children and other staff there have been screened.

The declaration of a public health emergency Thursday allowed the federal government to expedite monkeypox investigations and approve grants, but did not invoke the FDA’s emergency powers. Changing the injection mode would require a second type of emergency declaration, giving the Food and Drug Administration more leeway to issue emergency authorizations.

Federal agencies may grant emergency use authorizations for products when they believe the potential benefits outweigh the potential risks. At the start of the coronavirus pandemic, the Trump administration issued the same type of emergency declaration that allowed the FDA to make Covid-19 vaccines available to Americans many months before full regulatory approvals were granted.

dr Califf, the FDA commissioner, said Thursday regulators would continue to ensure the vaccine is administered in a safe and effective manner. He said regulators would likely decide in the next few days whether to go with the intradermal strategy, but that things “are looking good at the moment” — a comment some outside experts said preceded the considerations of professional regulators.


Emily Cochrane and Tracey Tully contributed coverage.