Stretching monkeypox injections is the latest plan to fight the outbreak

Yellow fever was rampant in the Democratic Republic of Congo in 2016, without enough vaccines to stop the spread.

Around the same time, there was a global campaign to eradicate polio, and India was running out of polio vaccines for everyone.

Vaccinators in both countries have therefore turned to a technique called splitting – uncommon in the United States – in which a standard dose is divided into parts to allow more people to get at least some protection.

Long Island and the rest of the country — currently in a public health emergency due to monkeypox — may soon find out if using fractional doses of the rare monkeypox vaccine, given instead via a more difficile, can help slow the exponential spread of the virus.

On Tuesday, the US Food and Drug Administration approved fractional doses of the Jynneos smallpox vaccine to meet high demand as a global outbreak of monkeypox continues. According to Dr. William Moss, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, splitting is typically done by dividing each dose into five parts, resulting in five times as many doses.

“I won’t say it’s really common, but this problem arises when there is an obvious shortage of vaccines, so often in the midst of an epidemic or an emergency,” he said, describing how fractionation has also been recommended by the World Health Organization to control meningococcal epidemics in Africa.

Not on Long Island — not yet

Fractionating monkeypox is not yet used on Long Island, where each county’s state-provided injections — nearly 11,000 have been allocated so far — are administered at more than a dozen clinics. operated by Nassau University Medical Center, Northwell Health, Stony Brook and Sun. River Health, according to representatives from each organization and from Nassau and Suffolk. Most said splitting was under consideration.

Public workers unload boxes containing yellow fever vaccines in Kinshasa, capital of the Democratic Republic of Congo, on July 20, 2016.
Credit: AFP via Getty Images/Eduardo Soteras

During the Sun River vaccination operation, full doses, each 0.5ml, are always given because government recommendations are so new, Chief Operating Officer Allison Dubois said: ‘What we are administering, these are the full doses until we get clarity on indicating an official change required.

Cadence Acquaviva, spokeswoman for the state Department of Health, said Wednesday that the agency is “reviewing new federal guidelines and considering all options.” New York City is also revising the guidelines, said Michael Lanza, spokesman for the city’s health department.

Acquaviva did not respond to a follow-up email asking whether a vaccination clinic can decide on its own to split doses, or whether the state must approve use of the technique.

Nationwide, appointments for the monkeypox vaccine have been scarce for months. These slots were booked almost immediately after becoming available online.

Splitting could multiply appointments by five. But with that comes the question: can providing one-fifth of a standard dose provide enough protection?

For monkeypox, the split dosage is based on a single trial published in 2015. In a conference call last week, an FDA official, Dr. Peter Marks, defended relying on the trial, the calling it reassuring and well built. Robert Fenton, the new White House monkeypox coordinator, called him a “game changer” who will “significantly increase the volume of vaccine doses across the country.”

But the manufacturer of the Jynneos monkeypox vaccine, Bavarian Nordic, wrote to the federal government: “We have some reservations”, citing concerns such as “the very limited safety data available”.

The number of monkeypox infections continues to increase exponentially. In the first 10 days of the month, cases globally roughly doubled in the United States, according to the Our World in Data website, which is run at the University of Oxford. New York, with 2,295 reported cases, is the epicenter of the US outbreak of 11,177 cases reported to date. There are 33 infected residents of Suffolk and 20 of Nassau, according to the state health department.

Dr. Anthony Fauci, President Joe Biden’s chief medical adviser, suggested last month that those most at risk in the current outbreak – men who have anonymous or random sex with other men, a current criterion to qualify for the vaccine – reduce their number of sexual partners.

“When you have a situation where you are not protected and you have a virus circulating in the community, [it] is just safe to chill it for a while until you get that protection,” Fauci said.

As for who would actually split the vaccine doses into fifths, the split would likely be done at the vaccination clinic, Moss said. A vial, which typically contains a single-use dose, would instead be drawn into five different syringes, he said.

But any unused vaccine — for example, because someone doesn’t show up for an appointment and no one else comes to get vaccinated — would spoil and have to be thrown away, Moss said.

Injection method requires more skill

When splitting, the dose is usually injected into the skin – intradermally – rather than subcutaneously, that is, under the skin. This is because there are more immune cells in the superficial parts of the skin resulting in a better immune response. It is not done intradermally with regular doses because it is more difficult to administer an intradermal injection correctly than a subcutaneous injection.

The Jynneos vaccine is given in two doses, four weeks apart, and someone returning for a second vaccine would typically receive another split dose if they received a first split dose, Moss said.

Daniela Weiskopf, assistant research professor at the La Jolla Institute for Immunology in San Diego, studied last year using a quarter of the recommended dose of Moderna’s COVID-19 vaccine. His conclusion: The lowest dose conferred about as much immunity as catching a coronavirus naturally, but not as much immunity as getting the full recommended vaccine dose, 100 micrograms.

Split dosing for monkeypox is not without controversy.

Using a more difficult injection method requires precision, with little margin for error. And some experts say the splitting here needs further research – since Jynneos clinical trials have been approved using the full dose, not a fifth of one.

“I think that would require further studies to carefully examine this,” she said.

For any vaccine, including monkeypox, the standard dosage is chosen by balancing the desired immune response against the virus with potential side effects, Weiskopf said: “What you want is a dose that induces the best response immune system with the lowest side effects, right? ? So you don’t just want to give as much as you can. You want to find the right place.

On Long Island, even if the supply was sufficient to meet the demand, Sun River faces a shortage of another type: personnel to inject pellets into weapons.

“The significant demand in public health is always affected by the recruitment and retention of support staff,” said Dubois. “We face the same vacancy issues, so we don’t have unlimited capacity to scale in those kinds of cases.”

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