The Washington PostDemocracy Dies in Darkness

Monkeypox vaccine maker voices concerns on U.S. dose-splitting plan

A health-care worker administers a Jynneos monkeypox vaccine in Los Angeles on Aug. 9. (Patrick T. Fallon/AFP/Getty Images)

The manufacturer of the only vaccine approved by the Food and Drug Administration to protect against monkeypox privately warned senior Biden health officials about their plan to split doses and change how the shots are delivered.

“We do have some reservations … due to the very limited safety data available,” Bavarian Nordic CEO Paul Chaplin wrote to Health and Human Services Secretary Xavier Becerra, and Food and Drug Administration Commissioner Robert M. Califf in a letter sent Tuesday and obtained by The Washington Post.

“It would have been prudent” to conduct further studies before overhauling the nation’s monkeypox vaccine strategy, Chaplin said, adding that his company had been “inundated with calls from U.S. state government officials with questions and concerns” about how to implement the new plan.

In interviews Wednesday, Biden administration officials acknowledged Bavarian Nordic’s concerns but said they would not affect their vaccine strategy.

“We’ve had conversations with them about this, and so has FDA,” Becerra said. “We wouldn’t have moved forward unless we thought it was safe and effective, and if FDA hadn’t dotted its I’s and crossed its T’s.”

Some Biden officials also believe Bavarian Nordic’s concerns stem from a potential loss in profits should the United States and other countries be able to stretch their existing vaccine supplies and reduce the need for future orders, according to three officials who were not authorized to comment. A representative for Bavarian Nordic who spoke on the condition of anonymity because they were not authorized to comment stressed that the company’s concerns were driven by safety.

Becerra and other officials Tuesday announced a strategy to stretch the nation’s limited supply of monkeypox vaccine, saying the plan would transform several hundred-thousand doses of Bavarian Nordic’s Jynneos vaccine into millions of potential shots. About 9,500 cases of monkeypox have been confirmed in the United States, overwhelmingly among gay and bisexual men, and local officials have pressed the White House to deliver more vaccine doses amid surging demand.

The plan is “a game changer,” Robert J. Fenton Jr., coordinator of the nation’s monkeypox response, told reporters Tuesday. “It’s safe, it’s effective, and it will significantly scale the volume of vaccine doses available.”

Under the new approach, health-care providers would split each single-dose vial of Jynneos into five doses. Rather than injecting the shots subcutaneously, a traditional way of delivering vaccines into the fatty tissue under the skin, the doses would be injected under the top layer of the skin. This approach, known as an intradermal injection, uses a thinner needle and less vaccine but leads to a small bubble forming on the surface of the skin.

Califf, who authorized the new approach Tuesday, cited a 2015 study into the two-dose vaccine that he said showed the strategy would be effective. Chaplin, the Bavarian Nordic CEO, was one of the authors of the study.

“The results of this study demonstrate that intradermal administration produces similar immune response to subcutaneous administration,” Califf said Tuesday. The FDA commissioner first publicly floated the dose-splitting strategy last week.

Peter Marks, the FDA’s top vaccine official, released a memo that reviewed the data for the new approach and addressed the need to stretch existing vaccine supplies.

“Approximately 1.6 to 1.7 million people are currently estimated to be at elevated risk of monkeypox in the U.S. and may need vaccination,” Marks wrote in his memo. “Therefore, 3.2 to 3.4 million doses of JYNNEOS would be required to immunize that population. However, only about half that number of doses are currently estimated to be available before the end [of] 2022,” before the United States adjusted its strategy as it did Tuesday.

But Bavarian Nordic on Wednesday noted that the FDA had approved its shots only to be delivered subcutaneously and called for further study, according to the company representative.

Outside experts also have raised concerns about whether the Biden administration is rushing to adjust its vaccine strategy, amid criticism that the nation does not have enough monkeypox vaccine to meet demand.

“No effort to protect people’s health should come without proper due diligence and research,” David Harvey, executive director of the National Coalition of STD Directors, said in a statement. “We have grave concerns about the limited amount of research that has been done on this dose and administration method.”

Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, and other public health experts also have said that changing the Jynneos vaccination strategy will require more health providers to be trained on the new approach.

But Biden officials maintain that the vaccine strategy change is necessary, given the surging demand and limited alternatives.

“We really have to look at what we have as countermeasures now, and we realized that, unfortunately, we simply did not have enough doses of the Bavarian Nordic vaccine,” a senior FDA official who spoke on the condition of anonymity because they were not authorized to comment publicly said in an interview Wednesday night.

Bavarian Nordic officials have signaled that they are open to other strategies to stretch limited vaccine supplies, such as delaying the second dose of the vaccine, as officials in New York, the United Kingdom and other monkeypox hotspots have done. Bavarian Nordic scientists are reviewing doses of Jynneos that were previously purchased by the United States but are past their shelf life to see if they remain viable and can be deployed in the outbreak.

Meanwhile, Bavarian Nordic officials had “limited notice” before Califf and other officials touted their potential plan to split the doses last Thursday, according to two individuals with knowledge of the communications who spoke on the condition of anonymity because they were not authorized to comment publicly.

The Biden administration has said it is still planning to procure more than 5 million additional single-dose vials from Bavarian Nordic by next year.