With the number of monkeypox cases continuing to grow, health officials have encouraged providers to look for a broader range of potential symptoms, and the United States has purchased an additional half a million vaccine doses for its stockpile.

Monkeypox: 3 ways the outbreak could unfold in the US

No evidence of airborne monkeypox transmission, officials say

So far, more than 1,450 confirmed cases of monkeypox have been reported worldwide, with the United States currently reporting 65 cases across 17 states and the District of Columbia.

In response to the growing number of cases, CDC last week raised its monkeypox alert to "level 2," the second highest travel advisory alert from the agency. Under this advisory, travelers are recommended to "practice enhanced precautions," including avoiding contact with infected patients and seeking medical care for any unexplained skin rashes or lesions.

According to CDC, monkeypox primarily spreads through close contact with an infected person or items that they may have touched, such as bedsheets. "All the cases we've seen to date in this outbreak are related to direct contact, either through skin-to-skin contact or through bed sheets," said CDC Director Rochelle Walensky.

In addition, the agency acknowledged that monkeypox may sometimes be spread through "droplet transmission" by saliva or large respiratory secretions, but said there is no evidence to suggest the virus is airborne.

"When we consider airborne transmission at the CDC, we're talking about small viral particles that become suspended in the air and can stay there for long periods of time," Walensky said. "We have not seen documentation of that through our experience with this virus or with prior similar viruses."

However, the World Health Organization and other health experts say airborne transmission, particularly over small distances, continues to be a possibility, and precautions, including masking for those in close contact with infected patients, may be necessary.

"Airborne transmission may not be the dominant route of transmission nor very efficient, but it could still occur," said Linsey Marr, an expert on airborne viruses at Virginia Tech.

According to the New York Times, some U.S. monkeypox patients have said they do not know when or how they were infected by the virus, suggesting some level of community transmission may be occurring. And if these patients were infected without close contact, "it's possible that airborne transmission has been occurring more than we realize," Marr said.

Providers prepare for monkeypox cases

CDC last week said it is working to expand the range of potential monkeypox symptoms that clinicians should look for, especially since recent cases have presented differently than the "classic" monkeypox cases seen in Africa.

In addition to more common symptoms, such as fever, headache, swollen lymph nodes, and rashes or lesions, some patients have also experienced proctitis, an inflammation of the rectum lining. CDC has also warned clinicians to not rule out monkeypox in patients with sexually transmitted infections since there have been reports of co-infections with syphilis, gonorrhea, chlamydia, and herpes.

"We are definitely working to expand information to clinicians, so that they know if additional symptoms should trigger thoughts of monkeypox," said Jennifer McQuiston, incident manager and deputy director of CDC's division of high consequence pathogens and pathology.

Hospitals have also begun making their own preparations to help control the current monkeypox outbreak, including screening patients, increasing decontamination and cleaning procedures, and wearing appropriate safety gear when interacting with infected patients, Modern Healthcare reports.

"Recent lessons learned during the COVID-19 pandemic—when conducting case finding, contact tracing, deploying vaccination teams and communicating messages to the public—will be helpful in managing this outbreak," said Bernard Camins, medical director for infection prevention at Mount Sinai Health System.

The US purchases an additional 500K vaccine doses

Last month, CDC released doses of a smallpox vaccine from the U.S. emergency stockpile for individuals who would benefit from them most, 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 Nordic and was approved by FDA in 2019 to prevent both smallpox and monkeypox. Currently, the United States has around 70,000 doses of Jynneos in its stockpile, and the federal government on Friday placed an order for 500,000 more.

According to Dawn O'Connell, assistant secretary for preparedness and response at HHS, around 300,000 doses will be delivered in the next few weeks, and the remainder will be delivered later in the year.

"We have tests for monkeypox. We have vaccines for monkeypox, and we have treatments for monkeypox," said Raj Panjabi, the White House's senior director for global health security and biodefense. "We have a multipronged approach to deploy those tools to ensure we're fighting this outbreak as effectively as possible." (Mandavilli, New York Times, 6/10; Walker, MedPage Today, 6/10; Scribner, Axios, 6/10; AHA News, 6/10; Diamond, Washington Post, 6/10; Mahr, Politico, 6/10; Devereaux, Modern Healthcare, 6/10; Knutson, Axios, 6/10; Payne, Politico, 6/10; Bean, Becker's Hospital Review, 6/10; Mosbergen, Wall Street Journal, 6/10)