美国国家公共电台 NPR--Is there enough monkeypox vaccine to go around? Maybe yes, more likely no（在线收听）

Is there enough monkeypox vaccine to go around? Maybe yes, more likely no

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As monkeypox cases continue to mount – topping 31,000 cases globally – governments of wealthy nations have been scrambling to buy vaccines. But what's available for the rest of the world?

NPR spoke with two people in a position to know: Matt Linley is with Airfinity, an independent, London-based analytics company that has been tracking production and deliveries of monkeypox vaccine. Dr. Phiona Atuhebwe coordinates the introduction of new vaccines in Africa for the World Health Organization. Here are eight takeaways.

1) Vaccine options are limited

In theory there are at least three existing vaccines that could be used to protect people from monkeypox. But one is not recommended for widespread use. It's a vaccine against smallpox called ACAM2000 that the United States' Food and Drug Administration has now made available for use against monkeypox under what's called an "investigational" protocol; in rare cases it may cause dangerous side effects such as swelling of the heart.

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Another option, developed in Japan, "has had significant production issues," says Airfinity's Linley. "So they've been unable to scale up any significant amount of production to use it outside of Japan."

As a result, in practice, notes Linley, countries are currently turning to only one vaccine: the Imvanex vaccine often referred to as JYNNEOS and approved by the U.S. FDA specifically for monkeypox in addition to smallpox. The catch is that only one company makes it – Denmark-based Bavarian Nordic.

2) Supply is also limited

In an email, a spokesperson for Bavarian Nordic told NPR that the company has the capacity to produce 30 to 40 million doses of JYNNEOS annually. With the recommended two-dose regimen, this would be enough to cover 15 to 20 million people. (The number of individuals covered could presumably be expanded even further to 100 million people if other countries follow the lead of U.S. officials – who, in an effort to stretch the current U.S. supply, this month approved a plan to cut each dose by a fifth by using a different method for injecting the vaccine.)

But Linley is skeptical that Bavarian Nordic's production capacity is as high as the company claims. "At least from what's known about Bavarian Nordic's deliveries [to date], they are significantly lower than we would expect" if the company really were able to produce 40 million annually, he says. As to what Bavarian Nordic's true capacity is, Linley thinks it might be more like 20 million annually. But he adds "with the initial complications that they've had and the lack of data that we have [from them], it's hard to come up with a proper estimate."

3) There is a best case scenario where supply meets need

How does this admittedly fuzzy picture of the likely JYNNEOS supply match up against the likely worldwide need?

To get a sense, Linley first considered the population among whom monkeypox is currently spreading in the current outbreak. Right now that is overwhelmingly men who have sex with men, most particularly with multiple partners. There is no known figure of how many people in the world are in this category, says Linley. So to come up with an estimate, Linley turned to statistics that can serve as proxies for it – and that match up with the eligibility criteria that several countries are using to ensure their vaccine is given to those most at risk: Specifically men who are HIV positive and men who are taking PrEP, a medication that can reduce a person's chances of contracting HIV. Linley cautions, however, that this is a very imperfect proxy, because many men who are taking PrEP or who are HIV positive are not men who have sex with men or who have sex with multiple partners.

That said, Linley estimates that this target population encompasses 18 million people worldwide. It's possible that just a fraction of them would need to be vaccinated in order to halt the outbreak, says Linley. And in that case, at least within a few months, Bavarian Nordic should be able to produce sufficient quantities of JYNNEOS to accomplish that.

4) But many other scenarios are worrisome

The trouble is that this best case scenario falls apart quickly if other potential developments are factored in. For instance, what if all 18 million people in the initial target population need to be vaccinated rather than just a fraction? Linley estimates that even at Bavarian Nordic's stated capacity it would take until November to produce enough vaccine for just the first dose. And what if the outbreak becomes sufficiently large that it becomes necessary to vaccinate all health-care workers? That would bring the total who need the vaccine to more than 62 million, says Linley.

Less likely – but even more dire – is what Linley has dubbed the "extreme" scenario in which monkeypox starts spreading among children, who are at higher risk of developing severe complications from the disease. That would bring the number of people requiring vaccination to 1.5 billion.

5) Even the U.S. is struggling to get doses

Although Bavarian Nordic has ramped up production, at the moment the available supply is so limited even wealthy countries are struggling to obtain doses.

Take the U.S., which with nearly 10,000 cases has world's highest count and which appears to have the largest contract with Bavarian Nordic. The U.S. had virtually no doses at the start of the outbreak in May. Since then, only about 1.1 million doses have actually been delivered. U.S. officials say another 150,000 doses should arrive in September and another roughly 150,000 before the end of the year, bringing the expected U.S. supply to just 1.4 million doses.

The U.S. also has an additional contract with Bavarian Nordic to get 5.5 million more doses this year and next using material that the U.S. had purchased from the company years ago. But it's unclear how soon those doses will reach the U.S., because first the material needs to be put into vials — or "filled."

Asked about the timeline, a spokesman for Bavarian Nordic told NPR that the company is "partnering with a U.S.-based contract manufacturer to expedite filling."

In the meantime, to stretch the current supply, U.S. officials are supplementing the one-fifth dose strategy with yet another plan: They've instructed Bavarian Nordic to test about 1 million expired JYNNEOS doses in the U.S. reserve to see if they are still usable.

6) Other wealthy countries are worse off than the U.S.

It's difficult to know precisely how many JYNNEOS doses each country in the world has contracted with Bavarian Nordic to obtain because both pharmaceutical companies and nations tend to keep much of this information confidential. But based on available reports, Linley says that almost all the contracts to date appear to be with wealthy countries. (Bavarian Nordic declined NPR's request to comment on Linley's statistics.) For instance Canada has contracted to get 750,000 doses; Australia as many as 450,000 doses; France 250,000; Germany 240,000; the United Kingdom 154,000; Israel 10,000 doses. There's also an undisclosed European Union country that has a contract for 1.5 million doses, and the European Union as a whole has a contract for an additional 164,000 doses.

But so far, like the U.S., most of these countries have seen only a fraction of these doses delivered – if at all. Germany and the EU have received 50,000 each, the U.K. 54,000 and Israel 5,600. That's a total number of deliveries of under 160,000 doses.

7) The rest of the world is being left out

Last week Brazil – which currently ranks sixth in confirmed monkeypox cases with more 2,000 infections – announced that through the auspices of the Pan American Health Organization it too had reached a deal with Bavarian Nordic: More than 20,000 doses will be shipped to Brazil in September and another 30,000 in October.

Beyond that it appears that the vast majority of the dozens of middle-income and low-income countries with current outbreaks have not secured any JYNNEOS vaccine.

8) Per usual Africa is coming in last

The inequity is particularly stark in Africa, where monkeypox had been endemic in several countries for years before the current outbreak. For now, at least, official case numbers remain relatively low in African countries. Still that could always change – or the official counts could be missing cases – notes WHO Africa's Dr. Phiona Atuhebwe. So the lack of availability of monkeypox vaccine is galling.

"It's just the same as how we were with COVID," she says. "It is just history repeating itself. Africa always gets [vaccines] last."

Indeed, largely for this reason, adds Atuhebwe, WHO is not stressing vaccination as the main strategy for combating the monkeypox outbreak, focusing instead on surveillance and contact tracing.

"We've learned to deal with reality, " says Atuhebwe with a sigh. "We push for more access to better tools to ensure that the African population is protected. But we've learned to work within reality."