US health officials on Tuesday authorized a plan to extend the nation’s limited supply monkey pox vaccines by giving people just one-fifth of the usual dose, citing research showing that reduced doses are also effective.
The so-called dose-saving approach also calls for using the Jynneos vaccine by injecting it just under the skin rather than into deeper tissue – an approach that could better improve the immune system. The recipient will still receive two injections four weeks apart.
The highly unusual move is a stark admission that the United States currently lacks the supplies needed to immunize everyone seeking protection from the rapidly spreading virus.
That number includes the 1.6 million to 1.7 million Americans considered by federal officials to be most at risk for the disease, mostly men with HIV or men at higher risk. Vaccinating that group would require a full dose about three times more than the roughly 1.1 million that officials have provided.
The White House monkeypox response coordinator, Robert Fenton, said the plan would help the US “get ahead of the virus”.
“It’s safe, it’s effective, and it will greatly expand the number of doses of vaccine available to communities across the country,” Fenton told reporters.
The Biden administration declared monkeypox a public health emergency last week in an effort to slow the growing outbreak that has infected more than 8,900 Americans. Officials announced a separate decision on Tuesday allowing the Food and Drug Administration to expedite the review of health products or new uses for them, such as dose-saving techniques for Jynneos.
The FDA has authorized the new approach for adults 18 years of age and older who are at high risk for monkeypox infection. The agency says younger people can also get the vaccine if they are considered high risk, although they should be traditionally vaccinated.
This announcement represents a face from last month, when the FDA and other agencies repeatedly emphasized that two full doses of the vaccine were needed for adequate protection.
But regulators now point to a 2015 study that found vaccination with one-fifth of a traditional dose produced a strong immune system response comparable to that of a full dose. About 94% of people who received the smaller dose had sufficient levels of antibodies against the virus, compared with 98% of those who received the full dose, according to research funded by the Institute of Health, according to research funded by the National Institutes of Health. National Health.
The NIH is planning to further test the technique in the coming months, according to the agency.
Vaccine manufacturers often formulate their vaccinations to provide sufficient protection, so it is not uncommon that a smaller dose could still prove effective.
However, some experts and advocates have warned that there is little data to support the policy and fear it could backfire if it reduces the effectiveness of the vaccine.
“We have serious concerns about the limited amount of research that has been done on this dosage and method of management, and we fear that,” said David Harvey of the National Coalition of STD Directors. it will give people a false sense of confidence that they are protected. , in a statement.
Smaller doses also require another injectable drug that penetrates only the top layer of skin, rather than the lower layer between skin and muscle. It’s a less common technique, which may require training for some doctors. It is also associated with more side effects such as redness, itchiness, and swelling.
The shallower injection is thought to help stimulate the immune system because the skin contains more immune cells that target foreign invaders.
The Centers for Disease Control and Prevention said it would provide educational material on the technique along with a broader awareness campaign for US health departments.
Vaccine dosing is common in Africa and other parts of the world with limited medical resources. In recent years, the World Health Organization has endorsed an approach to tackle outbreaks of yellow fever, polio and other diseases.
“This is not an uncommon situation,” said Dr. William Moss of the Johns Hopkins Center for Vaccine Access. “It depends on public health decision-making: In the midst of an outbreak where you don’t have enough supplies, do you make this trade-off?”
When the first COVID-19 vaccine was made available at the end of 2020, the UK government made it a priority to give the first dose to as many people as possible before giving the second vaccine.
Both the UK and Canada have adopted a single-dose vaccine strategy that prioritizes those facing the greatest risk of monkeypox. And health departments in several major US cities have adopted a similar strategy amid limited supplies, including New York, San Francisco and Washington.
US officials have shipped more than 617,000 full doses of the vaccine to state and local health departments and plan to distribute 380,000 more in the coming weeks. To date, it has been recommended for people who have been exposed to monkeypox or are likely to have been infected with it by recent sexual contact in places where the virus is spreading.
The Biden administration has been criticized for not quickly preparing millions of additional doses of the drug from the nation’s strategic national stockpile. Officials have ordered 5 million shots since July, but most are not expected to be delivered until 2023.
The US government owns a large quantity of vaccine material equivalent to 16.1 million doses under a contract with the Danish manufacturer Bavarian Nordic. But the material needs to be sealed in jars, a process that is expected to take months as the small company takes orders from other countries.
HHS responded to criticism last week about the speed and timing of government vaccine decisions.
“We’ve been thinking hard about how and when to use a bulk vaccine because once you remove it from the bulk, you’re going to lose years of shelf life,” a spokesperson said in a statement. an emailed statement.
The FDA approved the Jynneos vaccine in 2019 to prevent smallpox and smallpox in monkeys, based in part on studies in monkeys. Animals vaccinated with two doses were more than twice as likely to survive as those uninfected with monkeypox, according to FDA labeling.
Additional human studies have shown that people vaccinated with Jynneos have similar immune responses to those given the older smallpox vaccine. But Jynneos has not been tested in humans with monkeypox or its relative smallpox, which was ruled out decades ago.
That is typical of many vaccines and drugs in the national stockpile to treat rare or deadly pathogens such as anthrax or bubonic plague.
The US government has spent more than $1 billion developing and stockpiling the lyophilized vaccine, which replaces the previous liquid version with a shorter shelf life. Bavarian Nordic has a 10-year contract with the US to provide the new vaccine.
© 2022 Canadian Press
