WASHINGTON — It sounded like a simple solution to the monkeypox vaccine shortage: By changing the way doses are administered, the federal government could vaccinate five times as many people with the money it has.
But this approach — injecting a fifth of the current dose into the skin instead of the full dose into the base oil — isn’t all that simple in practice, experts say. And some federal officials worry about changing the method without more research, but Dr. Food and Drug Administration Director Robert M. Califf on Thursday described the proposal as promising.
Some outside experts are also urging caution. “From a basic science perspective, it should work,” said Dr. Jay K. Varma, director of the Cornell Center for Pandemic Prevention and Control. “But of course in life, in science, there are a lot of things that we think should work, and then when we actually do them, they don’t.”
Extending Vaccine Doses Ginneos helps the federal government tackle the challenge partially on its own. Despite investing more than $1 billion to develop a two-dose vaccine against monkeypox and smallpox, the government has only 1.1 million shots on hand because it has been slow to order bulk vaccine stocks back into vials.
That supply is enough to cover 550,000 people, but three times as many doses are needed to cover the 1.6 million to 1.7 million Americans at high risk of monkeypox, according to the Centers for Disease Control and Prevention. So far, the virus is spreading through skin-to-skin contact during sex among gay and bisexual men, the CDC says.
Some federal officials hope that by injecting smaller doses of the vaccine between the layers of the skin, the Biden administration can stop the outbreak before it spreads.
But some experts argue that this method has not been studied enough. They also warn that some vaccinators will need training to properly deliver vaccinations, which could slow down vaccination efforts. Otherwise, the government may waste doses instead of saving them.
An intradermal injection involves carefully guiding a needle into the layers of the skin, a thin space that contains immune cells. If the vaccinator goes too deep and injects the dose into the oil, the patient may not get enough vaccine, experts say. However, if the needle is not inserted far enough, some of the vaccine may flow back.
“If you’re giving a lower dose and you’re not injecting it into the skin — you’re injecting it in the wrong place — you’re probably not giving the protective vaccine,” said Dr. Phil Krause, who retired last year as the FDA’s senior vaccine regulator, worked on the agency’s licensing of Jynneos. “If you’re asking to do it in millions of doses across the country, it’s a lot easier to make mistakes in vaccine administration.”
On the other hand, the method has its own experience. It was used in polio vaccination campaigns when doses were limited, and for rabies and tuberculosis skin tests.
What you need to know about monkeypox virus
What is monkey pox? Monkeypox is a virus similar to chickenpox, but the symptoms are less severe. It was discovered in 1958 after the disease appeared in monkeys kept for research. The virus was found mainly in parts of Central and West Africa, but in recent weeks it has spread to dozens of countries, infecting tens of thousands of people, mostly men who have sex with men. On July 23, the World Health Organization declared monkeypox a global health emergency.
“This is not a new concept,” said Dr. Anthony S. Fauci, President Biden’s chief medical adviser. “We were thinking about this years ago as a strategy when vaccines were in short supply.”
Vaccinators used special bifurcated needles in their smallpox vaccination campaigns, which allowed them to administer intradermal injections uniformly and cheaply.
Dr. John Beigel, deputy director of clinical research at the National Institutes of Health, said a government-sponsored study on Jyneos published in 2015 compared the intradermal approach with the standard injection method and elicited comparable levels of neutralizing antibodies. 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 was a better option to preserve the vaccine than a single shot, as some jurisdictions are now doing, because research shows that a single shot rarely triggers an immune response.
“A single dose is unlikely to be effective,” he said, adding that the intradermal method is “an acceptable way to go.”
Although the 2015 trial involved hundreds of participants, some experts point out that it was a single study that was limited in what it measured. NIH researchers were planning to test Ginneos’ intradermal strategy in a trial that would begin in a few weeks. But results weren’t expected until late fall or early winter, and that plan is now in place.
Dr. Dr. H. Clifford Lane, Clinical Director. According to the Fauci National Institute of Allergy and Infectious Diseases at the NIH, researchers can gain insights by following people who receive the vaccine, but a traditional clinical trial will provide a clearer picture.
“I can understand that if it’s clear why it’s being done,” he said of the intradermal strategy. “The question is: How can we expand existing equipment without significantly reducing efficiency?”
Another question is how well the vaccine works. It was licensed for use against monkeypox and smallpox in 2019 because studies showed it elicited a stronger immune response than the previous vaccine. According to federal officials, the drug itself was approved because it compared favorably with the previous vaccine.
Monkeypox is rarely fatal and no deaths have been reported in the United States. Symptoms usually resolve within two to four weeks. But with the eight cases reported at the end of May reaching 7,510, the administration is trying to improve vaccination rates and access to tests and treatment.
Currently, the epidemic is almost exclusively confined to men who have sex with men, and those with multiple partners are considered to be particularly at risk. But on Friday, the Illinois Department of Public Health reported five cases involving children, an adult who worked at a daycare center tested positive for the virus, and the children and other staff there were being tested.
Thursday’s declaration of a public health emergency allowed the federal government to expedite an investigation into the monkeypox and approve grants, but did not use the FDA’s special powers. Changing the injection regimen would require a second type of emergency declaration, which would give the Food and Drug Administration more leeway to authorize emergency use.
Federal regulators can grant special approval to products when they believe the potential benefits outweigh the potential risks. At the start of the coronavirus pandemic, the Trump administration issued the same emergency declaration, which allowed the FDA to make Covid-19 vaccines available to Americans months before regulators gave them full approval.
Dr. Califf, the FDA commissioner, said Thursday that regulators will continue to ensure that the vaccine is delivered safely and effectively. He said regulators will decide whether to use the intradermal strategy in the next few days, but it “looks good right now” — a comment that some outside experts say seems to be ahead of the debate on career regulators.
Emily Cochrane the and Tracy Tully contributed reporting.