Editor: Alyson Browett, MPH

Contributors: Christina Potter, MSPH, Lane Warmbrod, MS, MPH, and Rachel Vahey, MHS

The Johns Hopkins Center for Health Security will be analyzing and providing updates, as needed, on the confirmed and suspected monkeypox outbreaks that have been identified in the several nations in Europe and North America. If you would like to receive these updates, please sign up here.

Investigations into growing outbreaks of monkeypox virus continue in at least 15 countries where the disease usually is not endemic. As of publication, health authorities have identified 160 confirmed cases and at least 80 suspected cases in Australia, Austria, Belgium, Canada, Denmark, France, Germany, Greece, Italy, Israel, Netherlands, Portugal, Spain, Sweden, Switzerland, the US, and UK.* No cases have yet to be confirmed in South America, although Argentina has reported a suspected case. The European Centre for Disease Prevention and Control (ECDC) today issued a risk assessment warning that if the current outbreaks in Europe are not brought under control quickly, there is a risk that monkeypox could become endemic if the virus spreads into an animal population.

The WHO issued a Disease Outbreak News (DON) on May 21 describing the evolving outbreaks, saying the agency expects more monkeypox cases, including in additional countries, to be identified as surveillance expands. According to the WHO, the identification of confirmed and suspected cases with no travel to endemic areas in West and Central Africa constitutes a “highly unusual event.” Based on currently available information, a significant portion of the cases, although not all, have been identified among men who have sex with men (MSM). Contact tracing is ongoing to identify epidemiological links between cases, such as common contacts or travel history.

To date, all cases confirmed by PCR testing are infected with the West African clade of monkeypox, which historically is less virulent than the Congo Basin (Central African) clade. Sequencing results for some cases have been made publicly available, and these data collection efforts are ongoing. Some of the confirmed cases have been hospitalized, but their conditions are unknown. No deaths have been reported.

The US CDC issued a health advisory through its Health Advisory Network (HAN) on May 20 to raise awareness among clinicians to be alert for symptoms associated with monkeypox—including the characteristic rash, even without historically typical flu-like symptoms—and provide specific recommendations on how to address suspected cases. During a news conference while traveling in Japan today, US President Joe Biden said the US has sufficient doses of smallpox vaccine, which has been shown to be effective against monkeypox, to help contain any large outbreak. The US FDA has licensed 2 smallpox vaccines, one of which is authorized specifically for monkeypox. Several nations—including the US, UK, Spain, and others—are either administering or considering whether to administer smallpox vaccine to people who may have had a monkeypox exposure.

President Biden also said the US likely would not implement quarantine, although he said monkeypox is a “concern in that if it were to spread, it would be consequential.” Belgium on May 20 instituted mandatory isolation for monkeypox patients and recommended high-risk contacts self-monitor for symptoms for 21 days. The UK also urged individuals at high risk of monkeypox, including household contacts of confirmed cases or healthcare workers exposed to patients, to self-isolate for 21 days.

Human-to-human monkeypox transmission—which occurs through close contact with lesions, body fluids, respiratory droplets, or contaminated materials such as clothing or bedding—historically is rare, and the extent of transmission in these outbreaks is not yet understood. The WHO notes that anyone who has had close physical contact with someone with monkeypox is at risk of contracting the virus and there is a high likelihood that further cases with unidentified chains of transmission will be identified. UNAIDS encouraged media, governments, and communities to respond to the evolving situation with a rights- and evidence-based approach that avoids stigma.