Outbreak Alerts
Editor: Alyson Browett, MPH

Contributors: Christina Potter, MSPH, Eric Toner, MD, and Rachel Vahey, MHS, and Lane Warmbrod, MS, MPH
The Johns Hopkins Center for Health Security is analyzing and providing updates, as needed, on the monkeypox outbreaks occurring in several non-endemic nations worldwide. If you would like to receive these updates, please sign up here.
Recent Outbreaks Update as of June 8, 2022 at 1:00pm ET

As of 5:00pm ET on June 7, there were 1,088 confirmed cases of monkeypox in 29 countries outside the endemic regions of West and Central Africa, according to the US CDC. As of 1:00pm ET today, the Global.health database reports 1,204 confirmed cases and an additional 84 suspected cases. No deaths have been reported in the outbreaks in non-endemic countries. 

Scientists are beginning to understand that the outbreaks likely are signals that monkeypox has been silently spreading among humans in the newly affected countries for some time. There is a risk of monkeypox becoming established in non-endemic countries. Genomic surveillance data from the US and Europe show at least 3 distinct but related monkeypox strains. The CDC said that 2 different strains were sequenced from US monkeypox cases in 2021 and 2022, and those strains are different from the one causing the outbreak in and from Europe

Notably, the findings—showing multiple chains of transmission—make it increasingly less likely that the virus’s spread can be stopped entirely. In order to do so, significant and urgent actions need to be taken to reduce exposures by raising awareness, particularly among healthcare providers and in those communities that are disproportionately affected; isolating suspected and confirmed cases; and tracing and monitoring potential case contacts. Experts have also called for faster, more streamlined processes and more widespread availability of monkeypox testing in order to better characterize current spread, which the CDC is taking under consideration. Additionally, these outbreaks should serve as warning signs that we must pay more attention to diseases considered endemic to certain areas or among specific populations, as these diseases—monkeypox and others—pose biological threats to the world.

More information on cases detected in non-endemic countries is increasingly publicly available. The CDC published a June 3 MMWR report on the US outbreak in 9 states, describing the public health response to 13 confirmed cases with a total of about 400 possible contacts (there are now 35 confirmed US cases in 14 states and Washington, DC). The European Centre for Disease Prevention and Control (ECDC) published several reports in its journal, Eurosurveillance, describing characteristics of monkeypox outbreaks in the UK, Italy, Australia, and Portugal. A preprint report posted by The Lancet describes the clinical and epidemiological features of patients with confirmed monkeypox infection who presented at London sexual health clinics. All 54 patients included in the report are men who have sex with men with a median age of 41. Notably, 1 in 4 patients had a concurrent sexually transmitted infection (STI) and 94% presented with lesions in the anogenital region, suggestive of transmission through close skin to skin or mucosal contact, such as sexual contact.

Health agencies worldwide are working to raise awareness among frontline healthcare workers who might interact with potential patients, most of whom have never encountered monkeypox in their practice. Additionally, the WHO noted in its June 4 update that large gatherings pose a risk of amplifying outbreaks and attendees should be made aware of the risks. The ECDC and the WHO jointly published interim advice on risk communication and community engagement during the monkeypox outbreak in Europe, and the CDC published a robust situation summary webpage on monkeypox, including information for healthcare providers and health departments. 

The CDC also issued a travel warning on monkeypox, with a level 2 alert urging people to practice enhanced precautions. The agency initially listed mask wearing as a way to help prevent monkeypox transmission, without explanation, but later removed that recommendation “because it caused confusion,” according to a statement. Respiratory transmission of monkeypox has occasionally been documented during past outbreaks although transmission mainly occurs through close, prolonged contact. Still, CDC noted that healthcare workers and household members should consider wearing masks. Rosamund Lewis, the WHO’s technical lead on monkeypox, said in a briefing today that the risk of aerosol transmission is not yet fully understood.

The CDC also has distributed at least 1,200 monkeypox vaccine doses as post-exposure prophylaxis for people who have had high-risk exposures. The US has supplies of 2 vaccines: the JYNNEOS vaccine made by Bavarian Nordic that is approved for monkeypox, and the ACAM2000 vaccine made by Emergent BioSolutions that is licensed for smallpox and effective for monkeypox. JYNNEOS is the preferred vaccine for pre-exposure prophylaxis, according to the CDC Advisory Committee on Immunization Practices (ACIP). Bavarian Nordic plans to increase production of the vaccine this summer, with the capacity to produce 30 million doses per year. The CDC also is distributing doses of the antiviral tecovirimat to states. Given some of the risks to certain populations, such as pregnant women or immunocompromised people, posed by the use of the vaccines and antivirals, more clear guidance is needed for pre- and post-exposure prophylaxis and treatment of monkeypox patients. The WHO announced today it will soon be releasing guidance on clinical care, infection control and prevention, vaccination, and further guidance on community protection.