Reducing Monkeypox vaccine dosage is not an easy fix, officials say

(Bloomberg) – The U.S. government’s solution to the monkeypox vaccine shortage is so far causing only headaches for overstretched public health departments as the outbreak continues to grow in scale and scope.

The so-called dose-saving strategy allows those distributing the vaccine to use only a fifth of what is traditionally given in an attempt to extract more doses from the existing supply. While sounding good in theory, the move requires “a significant shift in operations” for local health departments, Chicago Public Health Commissioner Allison Arwady told a meeting of the Big Cities Health Coalition. And it could be weeks before clinicians start using this strategy, she said.

The Food and Drug Administration on Tuesday approved the emergency use of a different vaccination technique to expand supply of Bavarian Nordic A/S’s monkeypox vaccine, Jynneos. In the alternative method, the injections are given between the layers of skin rather than underneath. A lower dosage means a single vial can provide five injections instead of just one.

The United States leads the world in most monkeypox cases, surpassing 10,700 infections on Thursday. So far, the epidemic has disproportionately affected men who have sex with men and has spread mainly through close contact. Jynneos is given to people considered to be at high risk of being exposed to someone with monkeypox. US health officials estimate there are nearly 1.7 million people most at risk, but there are currently only about 400,000 doses left in US stockpile, which is nowhere near enough without a strategy to expand this supply. The vaccine maker, however, is not convinced that this is the right approach. Paul Chaplin, chief executive of Bavarian Nordic, expressed “reservations” about the new strategy. Human Services Secretary Xavier Becerra and FDA Commissioner Robert Califf. US health officials did not coordinate with the company before announcing the dose expansion strategy, he said. Now the company is trying to quickly collect additional safety and effectiveness data while helping state officials with the rollout. and local health departments had already done so despite pressure from US health officials. Although injecting vaccines between layers of the skin is safe and used in other types of procedures such as tuberculosis testing, it is less common than the more standard subcutaneous vaccination. The decision to switch strategies was largely based on a 2015 clinical trial that found little difference in effectiveness when Jynneos was administered between layers of the skin and subcutaneously.

Health experts, however, have expressed concern that a small clinical trial is not enough evidence to change the vaccination protocol. The lack of real-world efficacy data could also pose problems. For example, the 2015 clinical trial showed that there is more redness and swelling associated with the alternative approach, which could deter people from returning for their second dose, according to Michael Ganio, senior director of pharmacy practice and quality at the American Society of Healthcare System Pharmacists. The prospect of expanding the supply was initially greeted with relief, said Arwady from Chicago, but the reality quickly set in that it wouldn’t be so easy. Intradermal vaccination requires a special syringe and thinner needle, training for health workers, and a different mechanism for reporting information about the inoculation. And so far, public health services – often grossly underfunded – are doing so without additional financial support from the federal government. “We’ve been working on this for three months without money,” Arwady said, adding that the expectation is that public health departments can roll out monkeypox vaccines much like they did for Covid, for which he there was a lot more federal financial support. Most healthcare workers don’t know how to administer injections in this new way. For example, if the vaccine is administered too deeply, the smallest dose will not be effective, but if the injection is too shallow, vaccine fluid may leak out of the injection site, Ganio explained. The US Centers for Disease Control and Prevention has already begun rolling out educational materials for clinicians and is working with local health departments on additional training resources such as online videos. There are also serious security considerations. Clinicians should ensure that needles are not reused and vials are discarded eight hours after opening.

“This population might be at higher risk for HIV, hepatitis,” Arwady said. “There’s just a lot of training to make sure our procedures are good, our safety is good, people understand how we’re moving to multi-dose vials.”

Switching to the low-dose approach after three months also raises equity issues, some public health experts say. In U.S. cities hard hit by the outbreak, white people have so far received the majority of vaccines, according to data collected by Bloomberg. For example, in Chicago, 55% of vaccines went to white people, who make up only 44% of all monkeypox cases there. Across the country, minority communities are hardest hit by the outbreak, according to the CDC.

The message this sends to black and Latino people who may not have had early access to the vaccine is that “their health is only one-fifth that of white gay men who were able to get vaccinated,” according to Nick Diamond, a public health expert and co-investigator of the New York-based monkeypox study RESPND-MI.

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