New US monkeypox vaccine strategy could give supply a big boost, but much is unknown

Intradermal administration “may increase the number of doses available in emergencies,” the study said. Last week, the United States declared monkeypox a national public health emergency.

U.S. officials said Tuesday they plan to collect real-world data on the vaccine, with the National Institutes of Health to begin clinical trials.

A new federal strategy calls for two doses of the vaccine to be given 28 days apart, and states that those who received the first dose subcutaneously can receive the second dose intradermally or subcutaneously. It has been.

However, some people have concerns about moving to a low-dose intradermal strategy.

“While we understand the federal government is willing to seek solutions to eventually remedy the vaccine shortage, efforts to protect the health of the population will continue without proper due diligence and research. It should not be done, the directors said in a statement Tuesday.

“We have serious concerns about the limited amount of research that has been done on this dosage and method of administration, and fear that it will give people a false sense of confidence that they are protected. Raise red light after red light and rush forward without data on efficacy, safety, or alternative dosing strategies.”

The Chicago Public Health Department on Wednesday said it would go along with a federal plan to expand supplies of the monkeypox vaccine by alternatively switching to smaller doses, a move that happened overnight. It is not intended to

“I think it will take a few weeks before it’s more widely deployed,” said Dr. Alison Alwadi, Commissioner of the Chicago Public Health Service.

Other city health departments, such as Ohio’s Columbus Public Health Department, are still considering the new federal strategy and its impact on local responses.

“Because this guidance is new, it is currently being reviewed to determine the impact on vaccine efforts, staffing and supply,” Columbus Public Health spokesperson Kelly Neumann told CNN on Wednesday. I am writing in an e-mail from

The need for “formal clinical efficacy data”

The efficacy of Gynneos for monkeypox prevention was originally tested in animals exposed to the virus and can be inferred from the antibody responses seen in people who participated in clinical studies of smallpox.

However, the Jynneos vaccine was originally developed to help defend the nation against smallpox as part of a bioterrorism response effort. Therefore, there are still not many precise data on how well subcutaneous administration protects against monkeypox infection.

The FDA approved the Jynneos vaccine for the prevention of smallpox and monkeypox in 2019, but that approval was primarily to provide a live virus-free smallpox vaccine option. Prior to that, Sanofi Pasteur Biologics’ ACAM2000 was the only FDA-approved vaccine to prevent smallpox. Jynneos is the vaccine of choice in the current outbreak, as ACAM2000 has more potential side effects and is not recommended for people with significantly weakened immune systems.

“I never intended to use ACAM2000 or Jynneos for monkeypox,” he said. “They were effective against it, but they weren’t seen as developing it.”

When Jynneos was approved, FDA officials said its effectiveness in preventing smallpox was determined by a clinical study involving about 400 healthy adults. Half ACAM2000, half Jynneos.

“We don’t have clinical efficacy data, but what we know about the smallpox vaccine and the effectiveness of Jynneos against monkeypox in animals makes it likely that Jynneos is very effective,” Barouch said. said.

He added, “In general, vaccines are usually more effective at preventing serious consequences of disease than they are at preventing acquisition of infection by pathogens.”

“We can be confident that this will likely be a very effective vaccine, but the details in terms of exact numerical efficacy, and whether it will prevent infection or serious illness, will be difficult. We don’t really know the details, such as what it will be, at this point,” Barouch said. “I think people at high risk should get vaccinated, but I don’t think I can give very precise guidance on what that protection will look like at this point.”

Opportunity to “significantly improve” availability

“If the vaccine can be administered at low doses without risk of efficacy, low-dose intradermal injections make sense,” write Krause and Borio. “However, this strategy can also backfire. If there is a risk to efficacy, focus the full available dose of the vaccine on the highest-risk individuals: men who have sex with multiple male partners. , it might be better to maximize the chances of getting a vaccine.The outbreak is under control.”

During outbreaks, vaccines have been administered to health care workers treating monkeypox patients, close contacts of patients, and people. Those who were able to find a dose at the local clinic. The CDC estimates that at least 1.5 million people in the United States are eligible for monkeypox vaccination.

The US Department of Health and Human Services has provided more than 670,000 doses of Gynneos vaccine from the Strategic National Stockpile to support local monkeypox response efforts.

Also, because it is licensed for intradermal injection, “Of the 400,000 vials of vaccine in the SNS’s inventory that have been allocated but not yet distributed, it will provide up to 2 million doses using intradermal administration.” Additionally, any vaccine received by a jurisdiction will be subject to intradermal administration if it has not already been administered.”

Lane said the move to an intradermal strategy could “greatly improve” vaccine availability. Her clinic ordered the short syringes needed to administer the vaccine intradermally. This is the same one used to test for tuberculosis.

“I ordered them this afternoon,” she said Tuesday before the FDA issued its approval.

Lane is concerned that many of her patients will get monkeypox, and sees data from the ACAM2000 vaccine as a baseline for how well the Jynneos vaccine works against monkeypox. said.

“What we are educating people about is that we know from historical data that the ACAM2000 vaccine administered historically in Africa was about 85% protective against monkeypox. We know that these families of orthopoxviruses tend to respond to the same treatments, not only are vaccines somewhat effective,” Lane said.

She added that she expected no concerns regarding the new vaccination strategy.

“I don’t see any hesitation about vaccines, at least at this point,” she said.

Dr. Paulette Gray Riveria agreed that an intradermal strategy could be an effective way to expand supply.

“Scientists are actively working to determine whether immune cells under the skin can activate antibody responses with equal or greater efficiency compared to the subcutaneous route.”