WASHINGTON — It seemed like a simple solution to the monkeypox vaccine shortage: By simply changing the way doses are injected, the federal government could vaccinate five times as many people with its available supply.
But the approach — injecting a fifth of the current dose into the skin instead of a full dose into the underlying fat — isn’t really that simple, experts say. And some federal officials are concerned about changing the method without more research, even though Dr. Robert M. Califf, head of the Food and Drug Administration, described the proposal Thursday as promising.
Some outside experts also urge caution. “From a basic science perspective, this should work,” said Dr. Jay K. Varma, director of the Cornell Center for Pandemic Prevention and Response. “But of course there are a lot of things in life, in science, that we think should work, and then when we actually do them, they don’t.”
Stretching out the doses of the vaccine, Jynneos, could help the federal government resolve a situation partly of its own making. Despite spending more than $1 billion developing the two-dose vaccine to use against both monkeypox and smallpox, the government only has 1.1 million shots on hand, in part because it was slow to order the ones. bulk vaccine stocks for processing into vials.
That supply is enough to cover 550,000 people, but about three times as many doses are needed to cover the 1.6 million to 1.7 million Americans who the Centers for Disease Control and Prevention says are at a high risk of contracting monkeypox. For now, the virus has been spreading primarily through skin-to-skin contact during sex between gay and bisexual men, the CDC said.
Some federal officials hope that by injecting a smaller dose of the vaccine between the layers of the skin, called an intradermal injection, the Biden administration will be able to control the outbreak before it spreads more widely.
But some experts argue that this approach has not been sufficiently studied. They also warn that some vaccinators will need training to give the shots correctly, which could delay vaccination efforts. Otherwise, the government could end up wasting doses, not saving them.
Intradermal injection involves carefully guiding a needle into the skin layers, a thin space with immune cells. If a vaccinator goes too deep and inserts the dose into the fat, the patient may not get enough vaccine, experts say. But if the needle is not inserted far enough, some of the vaccine could leak back out.
“If you’re giving a lower dose and you’re not injecting it into the skin correctly, you may be injecting it in the wrong place, you may not be giving a protective vaccine,” said Dr. Phil Krause, a retired physician. . FDA’s senior vaccine regulator last year and worked on the agency’s licensing of Jynneos. “If you ask that this be done nationally in millions of doses, it is much easier for there to be errors in the administration of the vaccine.”
On the other hand, the method has a history. has been used in polio vaccination campaigns when doses have been limited, as well as for skin tests for rabies and tuberculosis.
What to know about the monkeypox virus
What is monkeypox? Monkeypox is a virus similar to smallpox, but the symptoms are less severe. It was discovered in 1958, after outbreaks occurred in monkeys kept for research. The virus was found mainly in parts of central and western Africa, but in recent weeks it has spread to dozens of countries and infected 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..
“It’s not a new concept,” said Dr. Anthony S. Fauci, chief medical adviser to President Biden. “We were thinking of this as a vaccine shortage strategy years ago.”
Vaccinators have used special forked needles in smallpox inoculation campaigns that have allowed them to perform intradermal injections more uniformly and economically.
Dr. John Beigel, associate director for 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 it elicited a comparable level of neutralizing 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 was a better option for preserving the vaccine than giving a single injection, as some jurisdictions are now doing, because research has shown that one injection does not elicit as strong an immune response.
“One dose is not likely to be effective,” he said, adding that the intradermal method “is an acceptable way to do it.”
Although the 2015 trial involved hundreds of participants, some experts say it was a single study limited in what it measured. The NIH researchers had been planning to test the intradermal strategy for Jynneos in A judgment which was scheduled to 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, clinical director of Dr. Fauci’s National Institute of Allergy and Infectious Diseases at NIH, said that while researchers could gain insight by following people who get vaccinated, a traditional clinical trial would provide a better picture. clear.
“I can understand doing 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 stretch current supplies without significantly compromising efficiency?”
Another question is how well the vaccine will actually work. It was licensed in 2019 for use against monkeypox and smallpox after studies showed it elicited a stronger immune response than an earlier vaccine. That drug itself was approved because it compared favorably with an earlier vaccine, federal officials said.
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 spiraling outbreak of eight cases reported in late May to 7,510 nowthe administration is striving to improve the vaccination rate and the availability of tests and treatments.
As of now, the outbreak is almost entirely confined to men who have sex with men, with those who have multiple partners considered at particular risk. But so far five cases involving children have been reported. On Friday, the Illinois Department of Public Health announced that an adult who worked at a day care center had tested positive for monkeypox and that the children and other staff were being tested.
Thursday’s public health emergency declaration allowed the federal government to speed up monkeypox research and approve grants, but did not invoke the FDA’s emergency powers. Changing the injection mode would require a second type of emergency statementgiving the Food and Drug Administration more latitude in issuing emergency use authorizations.
federal regulators can issue emergency product authorizations when they believe the potential benefits outweigh the potential risks. Early in the coronavirus pandemic, the Trump administration issued the same type of emergency declaration, allowing the FDA to make Covid-19 vaccines available to Americans many months before regulators issued full approvals. .
FDA Commissioner Dr. Califf said Thursday that regulators would continue to ensure the vaccine was administered safely and effectively. He said regulators would likely decide in the coming days whether to go with the intradermal strategy, but that “it looked good at the moment,” a comment that some outside experts said seemed to preempt deliberations by race regulators.
emily cochrane Y Tracey Tully contributed report.