Stalled monkeypox vaccines raise risk of spillover, wider outbreak

Concerns are mounting that the window of opportunity for containing the escalating monkeypox outbreak may be closing, with vaccine shortages leaving some at-risk groups waiting weeks to get jabbed.

Health professionals have warned that a failure to get the outbreak under control could see it spill over into other populations or species.

The U.K. Health Security Agency has said that it expects to run out of its initial batch of 50,000 vaccines within the next two weeks, and may not receive further doses until September. Meanwhile, other high-case countries are considering new inoculation methods amid dwindling supplies.

Bavarian Nordic — the sole supplier of the only approved vaccine for monkeypox — announced Thursday that it had signed a deal with contract manufacturer Grand River Aseptic Manufacturing to help complete orders of its Jynneos vaccine in the U.S. while freeing up capacity for other countries. The process is expected to take around three months to get up and running.

It follows reports Wednesday that the Danish pharmaceutical company was no longer certain it could meet rising demand, according to Bloomberg.

More than 35,000 cases of monkeypox have so far been confirmed in 92 non-endemic countries since the first was reported in the U.K. on May 6. Twelve have been fatal.

The World Health Organization on Wednesday warned that the spread of the virus was continuing apace, with cases rising 20% in the past week alone.

While anyone can be infected with monkeypox, the overwhelming majority of cases have so far been confirmed in gay and bisexual men who have sex with other men.

That has prompted an inoculation drive, specifically among advanced economies, aimed at protecting the most vulnerable with either pre- or post-exposure vaccinations. However, shortfalls in vaccine supply and delayed rollouts are increasing the risks of a wider outbreak, according to infectious disease specialists.

“We know from past outbreaks that if an outbreak is to be stopped you have a very short window of opportunity. At this point, we see this window of opportunity slowly closing,” Professor Eyal Leshem of Israel’s Sheba Medical Center, told CNBC Thursday.

That, in turn, could see the virus transmit more easily to other groups or begin to behave in different ways, said Leshem.

“As we see more cases, the chance of containing this disease are reduced. We may see spillover from the current population at risk to other populations,” he said, naming close contacts and household members, including children and pets, as potentially vulnerable groups.

The first known instance in this outbreak of an animal catching monkeypox from humans was reported earlier this week in Paris.

As countries await further vaccine supply, some are now trying alternate means of safeguarding vulnerable groups.

In a letter leaked to the BBC, the UKHSA said it would withhold some remaining stock purely for post-exposure patients, meaning other people seeking preventative care would have to wait.

Elsewhere, Spain — which has the most reported cases of a non-endemic country after the U.S. — last week requested permission from the European Medicines Agency to give people smaller doses of the vaccine in a bid to spread limited supplies more widely.

It follows similar dose-sparing plans backed by U.S. health regulators, which allow one vial of vaccine to administer up to five separate shots by injecting between the skin rather than below it.

Still, the WHO’s technical lead for monkeypox, Dr. Rosamund Lewis, said Wednesday that vaccines should not be seen as the only form of protection against the virus.

“Vaccines are not a silver bullet,” she said, noting that more data on their efficacy is still required. Current data comes from a small study in the 1980s, which found that smallpox vaccines are 85% effective at preventing monkeypox.

She recommended those who believe themselves to be at risk to consider “reducing their number of sex partners [and] avoiding group sex or casual sex.” If and when someone does receive a vaccine, they should also wait until it has the time to produce the maximum immune response before engaging in sexual intercourse, typically two weeks, she added.

Dr. Jake Dunning, senior researcher at the University of Oxford’s Pandemic Sciences Institute, agreed, noting that a brief drop off in vaccinations may not necessarily derail wider efforts to combat the virus.

“If it turns out that actually a large proportion of those at greatest risk of exposure have been vaccinated already, then a relatively short and temporary decrease in the rate of vaccine administration may not have a big impact in achieving the overall aim,” he said.