A new virus has emerged and stoked fears of another pandemic: monkeypox. Since May 2022, it has been detected in 29 U.S. states, the District of Columbia, and Puerto Rico among international travelers and their close contacts. On a worldwide scale, as of June 30, there have been 5,323 cases in 52 countries.
The good news: An existing vaccine can go a long way toward preventing a catastrophic outbreak. Because monkeypox is a close relative of smallpox, the same vaccine can be used—and it is about 85 percent effective against the virus, according to the World Health Organization (WHO).
Also on the plus side, monkeypox is less contagious with milder illness than smallpox and, compared to COVID-19, produces more telltale signs. Scientists think that a “ring” vaccination strategy can be used when these signs appear to help with squelching this alarming outbreak.
How it’s transmitted
Monkeypox spreads between people primarily through direct contact with infectious sores, scabs, or bodily fluids. People also can catch it through respiratory secretions during prolonged, face-to-face contact, according to the Centers for Disease Control and Prevention (CDC).
As of June 30, there have been 396 documented monkeypox cases in the U.S., and the CDC has activated its Emergency Operations Center to mobilize additional personnel and resources. The U.S. Department of Health and Human Services is aiming to boost testing capacity and accessibility. No Americans have died from monkeypox during this outbreak but, during the COVID-19 pandemic (February 2020 to date), Africa has documented 12,141 cases and 363 deaths from monkeypox.
Ring vaccination proved effective in curbing the smallpox and Ebola outbreaks. As the monkeypox threat continues to loom, scientists view this as the best vaccine approach.
A person infected with monkeypox typically has symptoms—for instance, fever and chills—in a contagious state, so knowing when to avoid close contact with others makes it easier to curtail than COVID-19.
Advantages of ring vaccination
For this reason, it’s feasible to vaccinate a “ring” of people around the infected individual rather than inoculating large swaths of the population. Ring vaccination proved effective in curbing the smallpox and Ebola outbreaks. As the monkeypox threat continues to loom, scientists view this as the best vaccine approach.
With many infections, “it normally would make sense to everyone to vaccinate more widely,” says Wesley C. Van Voorhis, a professor and director of the Center for Emerging and Re-emerging Infectious Diseases at the University of Washington School of Medicine in Seattle. However, “in this case, ring vaccination may be sufficient to contain the outbreak and also minimize the rare, but potentially serious side effects of the smallpox/monkeypox vaccine.”
There are two licensed smallpox vaccines in the United States: ACAM2000 (live Vaccina virus) and JYNNEOS (live virus non-replicating). The ACAM 2000, Van Voorhis says, is the old smallpox vaccine that, in rare instances, could spread diffusely within the body and cause heart problems, as well as severe rash in people with eczema or serious infection in immunocompromised patients.
To prevent organ damage, the current recommendation would be to use the JYNNEOS vaccine, says Phyllis Kanki, a professor of health sciences in the division of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health. However, according to a report on the CDC’s website, people with immunocompromising conditions could have a higher risk of getting a severe case of monkeypox, despite being vaccinated, and “might be less likely to mount an effective response after any vaccination, including after JYNNEOS.”
In the late 1960s, the ring vaccination strategy became part of the WHO’s mission to globally eradicate smallpox, with the last known natural case described in Somalia in 1977. Ring vaccination can also refer to how a clinical trial is designed, as was the case in 2015, when this approach was used for researching the benefits of an investigational Ebola vaccine in Guinea, Kanki says.
“Since Monkeypox spreads by close contact and we have an effective vaccine, vaccinating high-risk individuals and their contacts may be a good strategy to limit transmission,” she says, adding that privacy is an important ethical principle that comes into play, as people with monkeypox would need to disclose their close contacts so that they could benefit from ring vaccination.
Rapid identification of cases and contacts—along with their cooperation—is essential for ring vaccination to be effective. Although mass vaccination also may work, the risk of infection to most of the population remains low while supply of the JYNNEOS vaccine is limited, says Stanley Deresinski, a clinical professor of medicine in the Infectious Disease Clinic at Stanford University School of Medicine.
Other strategies for preventing transmission
Ideally, the vaccine should be administered within four days of an exposure, but it’s recommended for up to 14 days. The WHO also advocates more widespread vaccination campaigns in the population segment with the most cases so far: men who engage in sex with other men.
The virus appears to be spreading in sexual networks, which differs from what was seen in previously reported outbreaks of monkeypox (outside of Africa), where risk was associated with travel to central or west Africa or various types of contact with individuals or animals from those locales. There is no evidence of transmission by food, but contaminated articles in the environment such as bedding are potential sources of the virus, Deresinski says.
Severe cases of monkeypox can occur, but “transmission of the virus requires close contact,” he says. “There is no evidence of aerosol transmission, as occurs with SARS-CoV-2, although it must be remembered that the smallpox virus, a close relative of monkeypox, was transmitted by aerosol.”
Deresinski points to the fact that in 2003, monkeypox was introduced into the U.S. through imports from Ghana of infected small mammals, such as Gambian giant rats, as pets. They infected prairie dogs, which also were sold as pets and, ultimately, this resulted in 37 confirmed transmissions to humans and 10 probable cases. A CDC investigation identified no cases of human-to-human transmission. Then, in 2021, a traveler flew from Nigeria to Dallas through Atlanta, developing skin lesions several days after arrival. Another CDC investigation yielded 223 contacts, although 85 percent were deemed to be at only minimal risk and the remainder at intermediate risk. No new cases were identified.
How much should we be worried
But how serious of a threat is monkeypox this time around? “Right now, the risk to the general public is very low,” says Scott Roberts, an assistant professor and associate medical director of infection prevention at Yale School of Medicine. “Monkeypox is spread through direct contact with infected skin lesions or through close contact for a prolonged period of time with an infected person. It is much less transmissible than COVID-19.”
The monkeypox incubation period—the time from infection until the onset of symptoms—is typically seven to 14 days but can range from five to 21 days, compared with only three days for the Omicron variant of COVID-19. With such a long incubation, there is a larger window to conduct contact tracing and vaccinate people before symptoms appear, which can prevent infection or lessen the severity.
But symptoms may present atypically or recognition may be delayed. “Ring vaccination works best with 100 percent adherence, and in the absence of a mandate, this is not achievable,” Roberts says.
At the outset of infection, symptoms include fever, chills, and fatigue. Several days later, a rash becomes noticeable, usually beginning on the face and spreading to other parts of the body, he says. The rash starts as flat lesions that raise and develop fluid, similar to manifestations of chickenpox. Once the rash scabs and falls off, a person is no longer contagious.
“It's an uncomfortable infection,” says Van Voorhis, the University of Washington School of Medicine professor. There may be swollen lymph nodes. Sores and rash are often limited to the genitals and areas around the mouth or rectum, suggesting intimate contact as the source of spread.
Symptoms of monkeypox usually last from two to four weeks. The WHO estimated that fatalities range from 3 to 6 percent. Although it’s believed to infect various animal species, including rodents and monkeys in west and central Africa, “the animal reservoir for the virus is unknown,” says Kanki, the Harvard T.H. Chan School of Public Health professor.
Too often, viruses originate in parts of the world that are too poor to grapple with them and may lack the resources to invest in vaccines and treatments. “This disease is endemic in central and west Africa, and it has basically been ignored until it jumped to the north and infected Europeans, Americans, and Canadians,” Van Voorhis says. “We have to do a better job in health care and prevention all over the world. This is the kind of thing that comes back to bite us.”
Brittany Trang was staring at her glass test tube, which suddenly turned opaque white. At first, she had thought that the chemical reaction she tested left behind some residue, but when she couldn’t clean it off, she realized that the reaction produced corrosive compounds that ate at the glass. That, however, was a good sign. It meant that the reaction, which she didn’t necessarily expect to work, was in fact, working. And Trang, who in 2020 was a Ph.D. researcher in chemistry at Northwestern University, had reasons to be skeptical. She was trying to break down the nearly indestructible molecules of per- and polyfluoroalkyl substances or PFAS—the forever chemicals called so because they resist heat, oil, stains, grease, and water, and thus don’t react or break down in the environment.
“The first time I ran this, I was like, oh, like there's a bunch of stuff stuck to the glass, but when I tried to clean it, it wasn’t coming off,” Trang says, recalling her original experiment and her almost-disbelief at the fact she managed to crack the notoriously stubborn and problematic molecules. “I was mostly just surprised that it worked in general.”
In the recent past, the world has been growing increasingly concerned about PFAS, the pollutants that even at low levels are associated with a litany of adverse health effects, including liver damage, thyroid disease, high cholesterol, pregnancy complications and several cancers. Used for decades in manufacturing and in various products such as fire retardant foam, water-repellant clothes, furniture fabrics, Teflon-coated pans, disposable plates, lunch containers and shoes, these super-stable compounds don’t degrade in the environment. The forever chemicals are now everywhere: in the water, in soil, in milk, and in produce.
As of June 2022, the Environmental Working Group, a nonprofit watchdog organization, found 2,858 locations in 50 states and two territories to be heavily contaminated with PFAS while many farmers had been forced to dump their milk or spinach because the levels of these compounds were in some cases up to 400 times greater than what’s considered safe. And because PFAS are so pervasive in the environment and the food we eat, they are in our bodies too. One study found some levels of PFAS in 97 to 100 percent of participants tested.
Because these compounds were made to be very stable, they are hard to destroy. So far, the only known way to break down PFAS has been to “cook” them under very harsh conditions. The process, known as pyrolysis, requires upwards of 500 degrees Centigrade, high pressure and absence of oxygen, which is energy expensive. It involves sophisticated equipment and the burning of fossil fuels. Trang, who worked in the laboratory of William Dichtel, managed to break PFAS at 120 degrees Centigrade (248 F) without using strong pressure. After she examined the results of her process with various techniques that help quantify the resulting compounds and confirmed that PFAS had indeed degraded into carbon and the corrosive fluorine that clouded her glass, she was thrilled that it worked in such simple conditions.
“That's really what differentiates our finding from everything else that's out there,” Dichtel said about their discovery at a press conference announcing the study last month. “When we're talking about low temperatures, we're at 120 degrees Celsius and sometimes even quite a bit lower than that, and especially ambient pressure.”
The process used by Trang’s team was the exact opposite of the typical organic synthesis method.
Trang’s journey into PFAS degradation began with a paper she read about the nuances of the chemicals’ molecular structure. A long molecule comprised primarily of carbon and fluorine atoms, along with oxygen and hydrogen, it has what Trang describes as a head and a tail. At the head sits a compound called carboxylic acid while the fluorine atoms make up the tail portion, with the atomic bonds so strong they aren’t possible to break without harsh treatment. But in early 2020, Trang read that a solvent called dimethylsulfoxide, or DMSO, commonly used in labs and industry, can make the carboxylic acid “pop off” its place. The DMSO doesn’t react with carboxylic acid but sort of displaces it, leaving the rest of the typically indestructible PFAS molecule vulnerable.
Trang found that its exposed fluorine tail would react with another common chemical compound, sodium hydroxide, causing a cascade of reactions that ultimately unravel the rest. “After you have decarboxylated the head, the hydroxide is able to react with the tail,” Trang says. “That's what sets off a cascade of reactions that degrades the rest of the molecule.”
That pathway took time to figure out. Trang was able to determine that the molecule carboxylic acid head popped off, but before she was able to figure out the rest, her lab and the entire Northwestern University went into lockdown in early March of 2020. “I was able to do three experiments before the shutdown,” she recalls. For the next few months, she sat at home, reading scientific literature to understand how to continue the degradation process. “I had read a bunch of literature and had a bunch of ideas for what may or may not work,” she says. By the time she could return to work, she had a plan. “I added sodium hydroxide in my batch of experiments when the lab reopened.”
The process used by Trang’s team was the exact opposite of the typical organic synthesis method. “Most organic chemists take two molecules and squish them together to make one big molecule. It’s like taking two Legos and putting them together to make one thing that was larger,” she says. “What we are doing is kind of smashing the Lego with two bits and looking at what was left to figure out how it fell apart.” The team published their discovery in the journal Science.
Although very promising, the process isn’t quite ready for industrial applications, and will take time to adapt, Trang says. For starters, it would have to be scaled up to continuously clean large quantities of water, sewage or other substances that can be contaminated with PFAS. The process will also have to be modified, particularly when it comes to removing PFAS from drinking water because as an industrial chemical, DMSO is not suitable for that. Water companies typically use activated carbon to filter out PFAS and other pollutants, so once that concentrated waste is accumulated, it would be removed and then treated with DMSO and hydroxide to break down the molecules. “That is what our method would likely be applied to,” Trang says—the concentrated waste rather than a reservoir because “you wouldn't want to mix DMSO with your drinking water.”
There are some additional limitations to the method. It only breaks down one class of forever chemicals, but there are others. For example, the molecules of perfluoroalkane sulfonic acids, or PFSA, don’t have a carboxylic head that DMSO can displace. Instead, PFSA have a sulphonic acid as their molecular head, which would require a different solvent that still needs to be discovered. “There is certainly the possibility of activating sulphonates in similar ways [to what] we've done [with] carboxylates,” Dichtel said, and he hopes this will happen in the future. Other forever chemical types may have their own Achilles’ heels, waiting to be discovered. “If we can knock that sulphonated headgroup off the molecule and get to the same intermediates we get to in this study,” Dichtel added, “it's very reasonable to assume that they'll degrade by very similar pathways.” Perhaps another team of inquisitive chemists will take on the challenge.
The Friday Five covers five stories in research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.
Here are the promising studies covered in this week's Friday Five:
- A new mask can detect Covid and send an alert to your phone
- More promising research for a breakthrough drug to treat schizophrenia
- AI tool can create new proteins
- Connections between an unhealthy gut and breast cancer
- Progress on the longevity drug, rapamycin
And an honorable mention this week: Certain exercises may benefit some types of memory more than others