As the number of confirmed monkeypox cases worldwide continues to grow, the World Health Organization (WHO) said the disease presents a "moderate" risk to global public health. To contain the spread, CDC released stockpiled vaccines for certain individuals—and one Massachusetts hospital has already started vaccinating part of its exposed workforce.

Monkeypox is a 'moderate' risk to global public health

Monkeypox is a rare viral infection that begins with flu-like symptoms and progresses to a distinctive rash on the face and body. Transmission can occur via contact with bodily fluid, sores, or items contaminated by bodily fluid, but most often occurs via large respiratory droplets, which rarely travel more than a few feet. Most infections resolve within weeks, but some cases can be fatal, according to WHO.

Although the virus is rarely seen outside of West and Central Africa, where it is endemic, more than twenty countries worldwide, including the United States, Canada, and Spain, have recently reported monkeypox cases.

So far, there are more than 250 confirmed cases worldwide, and roughly 120 additional cases are under investigation. In the United States, there are currently 18 confirmed cases across several different states, including California, Colorado, Florida, Massachusetts, New York, Utah, Virginia, and Washington. No deaths have been reported from any of the confirmed cases.

"Currently, the overall public health risk at [a] global level is assessed as moderate considering this is the first time that monkeypox cases and clusters are reported concurrently in widely disparate WHO geographical areas," WHO said in a statement. In addition, the agency said that, given the wide geographic scope of cases, the virus "may have been circulating unrecognized for several weeks or longer."

Rosamund Lewis, WHO's technical lead for monkeypox, said she does not believe the monkeypox outbreak will escalate into a pandemic, but noted that there are still many unknowns about the disease, including how it is spreading around the world and whether smallpox's eradication increased people's vulnerability to monkeypox.

"We are concerned that individuals may acquire this infection through high-risk exposure if they don’t have the information they need to protect themselves," she said. According to Lewis, most monkeypox cases have been reported in gay or bisexual men, but anyone could be at risk for the disease, regardless of sexual orientation. Individuals should avoid contact with those who are infected.

"The situation is evolving rapidly and WHO expects that there will be more cases identified as surveillance expands in non-endemic countries," the agency said.

Health officials work to reduce spread, vaccinate those at risk

At the moment, the general public's risk of monkeypox appears to be low, but it may not stay that way. According to WHO, "immediate action from countries is required to control further spread among groups at risk, prevent spread to the general population and avert the establishment of monkeypox as a clinical condition and public health problem in currently non-endemic countries."

In the United States, health officials are currently testing monkeypox cases through a two-step process. First, local or state labs perform initial testing to identify whether a patient's sample is an orthopox, the viral genus monkeypox belongs to, and then CDC verifies whether the sample is indeed monkeypox.

Although there have been some concerns that this protocol could delay detection or treatment, both regional and federal health authorities have emphasized that any suspected cases are being treated as presumptive cases. "I want to emphasize that the orthopox test that they have is sufficient for managing patient care and contact tracing and all of those things," said Jennifer McQuiston, deputy director of the CDC's Division of High-Consequence Pathogens and Pathology.

However, McQuiston said officials are also considering how to expand testing capabilities in local or regional labs if it becomes necessary. "It's not an easy matter to shift the tests out to the states," she said. "And I think we're actively exploring what it would take. I'll just tell you that we're committed to, if it's possible, doing it as quickly as we can."

To reduce the potential spread of monkeypox, CDC last week released a smallpox vaccine from the U.S. emergency stockpile for individuals who would benefit the most from them, including people who have had close contact with monkeypox patients, health care workers, and people at high risk of developing severe illness from the virus.

The vaccine, Jynneos, is manufactured by Bavarian Nordric and was approved by FDA in 2019 to prevent both smallpox and monkeypox. Unlike an older smallpox vaccine, it has fewer adverse side effects and can be used for immunocompromised patients. On Friday, CDC's Advisory Committee on Immunization Practices recommended Jynneos for laboratory personnel and anyone responding to outbreaks of orthopox viruses, including smallpox and monkeypox—a decision that has been in the works for the past two years but gained new relevance with the current outbreak.

Last week, Massachusetts General Hospital became the first hospital in the United States to vaccinate a small group of its workers against monkeypox. These workers had been in close contact with a patient who was hospitalized with monkeypox from May 12 to May 20. This is the first time the vaccine has been administered in the United States outside of clinical trials, the Boston Globe reports.

"This certainly felt novel because this was the first time we were able to use [the monkeypox vaccine] in response to an outbreak,” said Paul Biddinger, chief preparedness and continuity officer for Mass General Brigham.

According to Biddinger, as many as 200 people had contact with the hospitalized patient, and it was "quite labor intensive" to determine exposure and risk, as well as develop communication and counseling materials about the Jynneos vaccine. So far, fewer than 10 people have been vaccinated.

"It took a huge number of people working all last week and through the weekend to make sure we could deliver the vaccines to those who wanted it and needed it," he said. " … It has been a real, real-time learning effort." (Bacon, USA Today, 5/30; Choi, The Hill, 5/27; Branswell, STAT News, 5/29; Purtill, Los Angeles Times, 5/28; Schnell, The Hill, 5/30; Joseph, STAT News, 5/27; Walker, MedPage Today, 5/27; Lazar, Boston Globe, 5/26)