In a world exhausted by two-plus years of the coronavirus pandemic, another disease, monkeypox, continues to spread more rapidly than ever before. It’s a very different virus from the one that causes COVID-19, and is much harder to transmit, but it can land patients in the hospital and even kill. Monkeypox can also leave the infected disfigured: The pus-filled lesions that pock the skin—anywhere from a few to thousands—can leave permanent scars.
So far, 61 countries on six continents have recorded 7,492 cases, with a 82 percent increase in new infections since June 27. In the United States, monkeypox has breached 34 states, the District of Columbia, and Puerto Rico. Cases currently number 700 and while most illness has been relatively mild, there have been three confirmed deaths in Africa. The disease is largely circulating in a particular network, men who have sex with men.
But it’s likely that "a significant number of cases are not being picked up," says World Health Organization Director-General Tedros Adhanom Ghebreyesus. Beyond limited testing, some patients present with relatively few lesions, further complicating the case count.
Transmission has entered uncharted territory, with monkeypox cases among people who haven’t traveled to Africa—where the virus is endemic—and infections popping up in new places. "There is simply no room for complacency—especially right here in the European Region with its fast-moving outbreak that with every hour, day, and week is extending its reach into previously unaffected areas," Hans Henri P. Kluge, the WHO Regional Director for Europe, said in a statement.
WHO’s Emergency Committee will reconsider whether the outbreak constitutes a global public health emergency the week of July 18. They noted that controlling the spread of monkeypox requires "intense response efforts."
This current multi-country outbreak was "a surprise," but "not surprising," says Rosamund Lewis, who serves as the monkeypox technical lead at the WHO. Cases have been rising for decades in Africa. An ongoing outbreak in Nigeria began in 2017 (and may be the origin of this current spread) and another in the Democratic Republic of the Congo (DRC) counted some 6,000 suspected cases in in 2020.
While COVID-19 cases dwarf those from monkeypox, experts are concerned that humans may infect wild animals in the U.S. or other nations, inadvertently creating new endemic reservoirs for the disease, says Andrea McCollum, an epidemiologist with the Centers for Disease Control and Prevention’s (CDC) 2022 Monkeypox Outbreak Response effort. Animals could then retransmit the virus to people, making it much more difficult—or impossible—to eradicate.
There are now global efforts to prevent the spread of monkeypox cases and avert another pandemic. Towards that end, public health officials are offering vaccination to those at risk. The Biden administration is ramping up delivery of vaccines which have been in tight demand.
Here’s what you need to know about the virus, risk, prevention, and whether you need a monkeypox vaccination.
What is monkeypox?
Monkeypox is a much less severe, less contagious cousin of smallpox. Both are orthopoxviruses, a genus of 12 DNA viruses that also includes cowpox and camelpox.
There are two distinct genetic clades, or varieties, explains Bernard Moss, a virologist at the U.S. National Institute of Allergy and Infectious Diseases (NIAID). One, Congo Basin monkeypox, kills one in 10 of those infected. The current global outbreak is confirmed to be the second variety, the less deadly West African monkeypox, which has a mortality rate of less than one percent.
It’s a zoonotic disease, transmitted to humans by animals. First discovered in 1958 among monkeys in a Danish research lab, the virus’s name may or may not be a misnomer. Small mammals are thought to harbor the virus in African rainforests where it’s endemic, but it can infect many mammals and has only been isolated in wild animals twice: a rope squirrel in the DRC in 1985 and a mangabey in Cote d’Ivoire in 2012. The actual disease reservoir(s) remain unknown.
Since the first known human case in 1970—when an infant boy was diagnosed in DRC—most infections have occurred in West and Central Africa. Early on, most were “spillover events,” contracted from hunting and butchering infected wild animals, says Lewis.
Close contact can then spread the virus between people. The lesions are contagious "little viral factories," says CDC’s McCollum. But until recently, the virus rarely spread beyond a few households within a community.
Though this disease was characterized at least 52 years ago, "we actually don't know nearly as much as we would like to," says Lewis.
Is it a sexually transmitted disease?
Though one of the initial cases infected a mother, father, and their infant in the United Kingdom, the current monkeypox outbreak has overwhelmingly affected men who have sex with men—99 percent among cases that have reported gender. For public health officials, it’s been challenging to educate the public without stigmatizing that community.
The outbreak was likely amplified by sexual behavior at raves in Spain and Belgium, David Heymann, a longtime WHO infectious disease expert, told the Associated Press. Those events seeded international spread, much like large gatherings disseminated COVID-19 during the early days of the pandemic.
But evidence suggests that monkeypox is not an STD, says Moss. When someone is symptomatic, it’s spread skin-to-skin—including through sexual behaviors—and can also be transmitted through contact with bedsheets, towels, or clothing.
Previous outbreaks in Africa have infected women, children, and men of all ages. "There are no guardrails. This virus is not necessarily going to stay within one gender or one population," warns Anne Rimoin, an infectious disease epidemiologist and professor at the University of California Los Angeles School of Public Health. That is already happening. The WHO has started seeing cases in children, Lewis says.
She calls this an evolving situation that must be carefully monitored. “I think we need to have our eyes wide open and be ready to react.”
Public education is key. "We don't want people to worry, but awareness is what you need to protect yourself," Lewis adds. "What we need is for each person to know their own risk…and manage it."
Are tests and vaccines readily available in the U.S.?
There are existing tests for monkeypox, which involve simply swabbing a lesion. Tests are then shipped to an in-state lab to confirm orthopox, then sent on to the CDC to confirm monkeypox. With a positive orthopox result, patients are being preemptively treated.
Despite existing U.S. Laboratory Response Network testing for infectious disease, advocates have complained of backlogs and delays in testing and results; demand is currently concentrated in urbans areas. To date, California, New York, Illinois, and Florida are the most affected, according to the CDC. To make tests more available, the Department of Health and Human Services (HHS) will be shipping orthopox virus tests to five commercial labs.
Vaccines have been hard to get, but that is changing. After the first U.S. case was logged on May 18, numbers surged and monkeypox vaccines were quickly depleted. On June 28, the Biden administration announced that it would distribute 56,000 additional doses, prioritizing areas with the greatest transmission. Another 240,000 doses will be distributed in the coming weeks, with a total of 1.6 million available by late fall.
There is no approved treatment specifically for monkeypox, but antivirals developed for smallpox may help, according to the CDC.
Should I get monkeypox vaccine? Who is being prioritized for vaccination?
"Vaccination of the general population is not warranted," says NIAID’s Moss. At present, the virus is only spreading within a small demographic.
But amidst this mushrooming outbreak, contact tracing is no longer possible. Some countries, including the U.S., have had to pivot, with plans to expand vaccination from just those with known contacts to include anyone at high-risk.
"Vaccination is best if it's given before someone gets infected," says Moss. Post exposure, the target window is four days, but people can be vaccinated up to two weeks after.
What is the difference between the two monkeypox vaccines—and when were they developed?
Edward Jenner, considered the founder of vaccinology in the West, successfully inoculated an eight-year-old boy against smallpox in 1796 using vaccinia virus—from cowpox. Two years later, researchers developed the first smallpox vaccine. Since orthopox viruses share 90 percent or more of their genetics, "a vaccine made against any one of them is protective against all of them," Moss says.
Unlike the situation with the dawning COVID-19 pandemic in 2020, the good news is that we have vaccines that should work against monkeypox, Lewis says. Two are available in the U.S. The Food and Drug Administration approved ACAM2000 in 2007 to prevent smallpox. It resembles the early vaccines, using live, mild vaccinia virus, and has been used by the military, laboratory workers, and other groups for decades. Those who were vaccinated against smallpox before the U.S. ended its program in 1972 should have some lingering immunity.
The current smallpox vaccines have never been tested in phase III clinical trials against either smallpox or monkeypox. While health professionals believe that smallpox vaccines work against monkeypox, "this has not yet actually been demonstrated in rigorous studies," says Lewis, "or even in ‘real life’ at this time."
Certain groups should avoid this live vaccine. They include those who are pregnant, as it can endanger an unborn child. The immunocompromised or those with skin conditions should also steer clear: the virus can spread uncontrolled. This vaccine can also be dangerous for those with cardiac problems, as it can trigger heart inflammation.
The second vaccine, Jynneos, carries far fewer side effects and is the only vaccine approved specifically for monkeypox.
However, along with awareness and appropriate caution, "[Vaccination is] key to reining this in and getting it under control," says McCollum.
Was this international outbreak unexpected?
Experts did not predict that monkeypox "would move through closely related social networks and across borders in the numbers that we’re seeing right now," says McCollum.
But there were warning signs.
In Africa, monkeypox cases began increasing after smallpox was globally eradicated in 1980 and vaccination campaigns ended: those vaccines cross-protected against all orthoviruses. As leftover immunity waned, monkeypox infections jumped, rising 20-fold from 1986 to 2007 in DRC.
Then, in 2018, officials tallied growing travel-related cases. "That raised our eyebrows," McCollum says. “We were becoming quite concerned that it was the tip of the iceberg."
Underlying environmental conditions were ripe for this to happen, says Lewis. She lists factors that increase risk of zoonotic diseases passing from wildlife to people: climate change and deforestation that open access to the forest, the need for protein, and sale of bush meat in markets.
"We all share one planet," she says, and we need research that helps us protect humanity and nature. "As long as we don’t have both those objectives in mind, we are going to keep getting into trouble."