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Also on the positive side, monkeypox is less contagious with milder disease than smallpox and, compared to COVID-19, produces more telltale signs. Scientists believe a ‘ring’ vaccination strategy can be used when these signs appear to be helping quell this alarming outbreak.
How it is transmitted
Monkeypox spreads between people primarily through direct contact with infectious wounds, scabs, or bodily fluids. People can also 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 cases of monkeypox in the United States, and the CDC has activated its emergency operations center to mobilize additional personnel and resources. The US Department of Health and Human Services aims to build testing capacity and accessibility. No Americans 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.
A person infected with monkeypox usually shows symptoms – for example, fever and chills – in a contagious state, so knowing when to avoid close contact with others makes it easier to reduce from COVID-19.
Advantages of ring vaccination
For this reason, it is possible to vaccinate a ‘ring’ of people around the infected individual rather than inoculating large swaths of the population. Ring vaccination has proven effective in curbing smallpox and Ebola outbreaks. As the threat of monkeypox continues to loom, scientists consider this the best vaccine approach.
With many infections, “it would normally make sense for everyone to vaccinate more widely,” says Wesley C. Van Voorhis, 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/monkey pox vaccine.”
There are two smallpox vaccines licensed in the United States: ACAM2000 (live Vaccine virus) and JYNNEOS (live, non-replicating virus). ACAM 2000, Van Voorhis says, is the old smallpox vaccine that in rare cases could spread diffusely through the body and cause heart problems, as well as a severe rash in sufferers. eczema or severe infection in immunocompromised patients.
To prevent organ damage, the current recommendation would be to use the JYNNEOS vaccine, says Phyllis Kanki, professor of health sciences in the division of immunology and infectious diseases at Harvard TH Chan School of Public Health. However, according to a report on the CDC’s website, immunocompromised people may have a higher risk of contracting a severe case of monkeypox, despite being vaccinated, and “may be less likely to develop an effective response after any vaccination.” , including after JYNNEOS”. .”
In the late 1960s, the ring vaccination strategy became part of the WHO mission to eradicate smallpox globally, with the last known natural case being described in Somalia in 1977. ring can also refer to the design of a clinical trial, as was the case in Somalia. 2015, when this approach was used to research the benefits of an experimental Ebola vaccine in Guinea, says Kanki.
“Given Monkeypox is spread through close contact and we have an effective vaccine, vaccinating high-risk people and their contacts may be a good strategy to limit transmission,” she says, adding that confidentiality is an important ethical principle that comes into play, as people with monkeypox should disclose their close contacts so that they can benefit from ring vaccination.
The rapid identification of cases and contacts, as well as their cooperation, is essential for ring vaccination to be effective. Although mass vaccination can also work, the risk of infection for most of the population remains low while the supply of the JYNNEOS vaccine is limited, explains Stanley Deresinski, clinical professor of medicine at the Clinic of Infectious Diseases at the Stanford University School of Medicine.
Other transmission prevention strategies
Ideally, the vaccine should be given within four days of exposure, but up to 14 days is recommended. The WHO is also advocating for more widespread vaccination campaigns in the segment of the population with the most cases to date: men who have sex with men.
The virus appears to spread through sexual networks, which differs from what has been seen in previously reported outbreaks of monkeypox (outside of Africa), where the risk was associated with travel to central or western Africa or to various types of contact with people or animals in these countries. local. There’s no evidence of transmission through food, but contaminated items 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 should 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 to the United States through imports from Ghana of infected small mammals, such as Gambian giant rats, as pets. They infected prairie dogs, which were also sold as pets and ultimately resulted in 37 confirmed human transmissions 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 via Atlanta, developing skin lesions days after arrival. Another CDC investigation yielded 223 contacts, though 85% were deemed minimal risk and the rest intermediate risk. No new cases have been identified.
How worried should we be
But how serious is the monkeypox threat this time around? “Right now, the risk to the general public is very low,” says Scott Roberts, assistant professor and associate medical director of infection control at Yale School of Medicine. “Monkeypox is transmitted by direct contact with infected skin lesions or by close contact for a prolonged period with an infected person. It is much less transmissible than COVID-19.
The incubation period for monkeypox – the time between infection and the onset of symptoms – is usually seven to 14 days, but can range from five to 21 days, compared to just three days for the Omicron variant. of COVID-19. With such a long incubation, there is a greater window to conduct contact tracing and vaccinate people before symptoms appear, which can prevent infection or lessen its severity.
But symptoms may present atypically or recognition may be delayed. “Ring vaccination works best with 100 percent adherence, and without a mandate, that’s not feasible,” Roberts says.
Early in the infection, symptoms include fever, chills, and fatigue. Several days later, a rash becomes noticeable, usually starting on the face and spreading to other parts of the body, he says. The rash begins as flat lesions that lift and develop fluid, similar to the manifestations of chicken pox. Once the rash scabs over and falls off, a person is no longer contagious.
“It’s an uncomfortable infection,” says Van Voorhis, a professor at the University of Washington School of Medicine. There may be swollen lymph nodes. The sores and rashes are often limited to the genitals and areas around the mouth or rectum, suggesting intimate contact is the source of spread.
Symptoms of monkeypox usually last two to four weeks. The WHO has estimated that deaths range from 3 to 6%. Although it is thought to infect various animal species, including rodents and monkeys in West and Central Africa, “the animal reservoir of the virus is unknown,” says Kanki, a professor at the Harvard TH Chan School of Public Health.
Too often, viruses come from parts of the world that are too poor to fight them and sometimes lack the resources to invest in vaccines and treatments. “This disease is endemic in central and western Africa, and it was virtually ignored until it spread north and infected Europeans, Americans and Canadians,” says Van Voorhis. “We need to do a better job of health care and prevention around the world. This is the kind of thing that comes back to bite us.