IDSA Explains Current State of Monkeypox in the US

This morning, the Infectious Diseases Society of America (IDSA) hosted a virtual media briefing about the current state of the monkeypox virus.

Reports of monkeypox infections have been growing across the world. These outbreaks are unusual is that most infected persons had not travelled to the Congo or West Africa regions, where monkeypox is endemic.

IDSA Fellows Erica S. Shenoy, MD, PhD, and Daniel R. Lucey, MD, MPH, FIDSA, FACP, gave an overview of monkeypox outbreaks in the US and around the world before opening the floor for questions.

Lucey began by explaining that atypical monkeypox infections were first identified during enhanced surveillance for smallpox. The 2 viruses are very similar, though notably different from varicella or “chicken pox,” which is a herpes virus. Because monkeypox is a relative of smallpox, we have vaccine options stockpiled in case it becomes necessary to deploy them.

Asked if or when these vaccines would be utilized, the experts discussed “ring vaccination,” a strategy of vaccinating the close contacts of infected persons. “Ring vaccination is not imminent,” Lucey said. Notably, however, Shenoy said that they are doing extensive contact tracing to get the close contacts of monkeypox patients post-exposure prophylaxis and vaccines.

There are currently about 600 confirmed cases of monkeypox, Lucey said, 18 of which are in the US. The experts emphasized that this means monkeypox is still very rare, especially in the US, but anyone who suspects they are symptomatic or are a close contact should “use common sense” and see a healthcare professional.

Importantly, none of the 600 cases have been fatal. Genome sequencing has revealed these infections are caused by the less deadly West African clade, rather than the more severe Congo Basin clade.

Shenoy said that there is not enough information to determine precisely how these individuals contracted monkeypox, but said she wouldn’t be surprised if the virus was spreading via person-to-person household transfer in the US.

The experts were careful to note that no certain populations are indicated as more susceptible to monkeypox, and thus any stigmatizing language should be avoided. The World Health Organization (WHO) and other public health agencies have noted that the outbreaks have appeared primarily among men who have sex with men (MSM). However, Lucey said, there is no evidence of increased transmission among MSM.

Answering a question about whether monkeypox can spread through vaginal or seminal fluid, Shenoy said there is no conclusive proof. It is more likely, she said, that skin-to-skin contact during sex is spreading the virus. Additionally, the signature monkeypox lesions are commonly appearing on or around the genitals, contributing to the erroneous assumption that monkeypox is a sexually transmitted infection (STI).

Because these infections occurring more among MSM, Lucey emphasized the importance of communicating prevention strategies to this community. However, all people should stay safe and symptom monitor.

Unrelated to these recent outbreaks, there have already been 1284 monkeypox infections reported this year, Lucey said. Most of the people currently infected in the US had not travelled to regions of Africa where monkeypox is endemic and had no connection to animals known to spread the virus. It remains unknown whether household pets can contract and spread monkeypox, but Lucey said that this research is ongoing.

The experts emphasized that more detailed information would be shared tomorrow at WHO’s World Health Assembly. This special meeting speaks to how seriously WHO is taking these monkeypox outbreaks, Lucey said.