The Biden-Harris administration released its national monkeypox virus outbreak response on Tuesday. The first phase of the campaign is to immediately expand access to the smallpox vaccine Jynneos for those at high risk of exposure—with 56,000 doses immediately available—and to scale up testing capacity to 10,000 tests weekly at 78 sites in 48 states.
Tests are also shipping to five commercial labs to expand access in communities. As of June 28, the US case count is 306. A study published in The Lancet Microbe which modeled the effect of traditional public health interventions—such as isolation when sick, contact tracing, vaccination and testing—could substantially shorten the duration of the outbreak. Without these measures, sustained localized outbreaks throughout the country should be expected.
One of the administration’s key strategies is leveraging local communities to get the word out about symptoms and vaccination. It appears to be working: in advance of Pride events, a New York City clinic offering vaccines for gay or bisexual men with multiple or anonymous sexual partners over the previous 14 days saw such a quick uptick of walk-ins that the clinic had to close within hours and shift to scheduling appointments through this week. Vaccination had previously been reserved for close contacts of persons known to be infected with monkeypox, but expanding access to those with a presumed exposure is intended to break transmission chains within the sexual networks where the virus has been detected.
The US response closely follows an announcement by the United Kingdom’s Health Security Agency (UKHSA) which began offering the smallpox vaccine Imvanex to gay and bisexual men last week. Canada is offering the same vaccine under a different brand name, Imvamune, to adults age 18 or older for post-exposure prophylaxis according to recommendations for the National Advisory Committee on Immunization (NACI). All three vaccines are manufactured by a Danish company, Bavarian Nordic. Initially created to prevent smallpox, also an orthopoxvirus, they are live attenuated (non-replicating) two-dose vaccines given four weeks apart.
Is this strain of monkeypox different?
The currently circulating monkeypox virus belongs to clade 3 of the West African strain, which is known to be milder than the Congo Basin strain. Scientists in Portugal were the first to sequence the strain of virus currently circulating and reported the presence of 50 mutations compared to the strain which caused a 2018-19 outbreak in Nigeria. These mutations in the DNA sequence likely evolved in response to host defense mechanisms, and are continuing to slowly evolve as the virus adapts to human transmission. It is likely that this particular sequence was transmitted at a super spreader location, such as a sauna where sexual encounters happen, then rapidly emerged elsewhere via travelers.
Should I be worried about another pandemic?
At this point the World Health Organization considers the overall global risk of the outbreak to be moderate. The virus is not as good at transmitting between people as SARS-CoV-2—it requires close contact between sexual partners or household contact sharing contaminated items. The incubation period is about two weeks, and those seeking post-exposure vaccine would ideally be vaccinated within 4 days but up to two weeks is also considered potentially helpful.
What does monkeypox look like early in the disease?
The first symptoms with this strain are just one or a few lesions, but in some cases no skin lesions are present. The rash may look like a pimple or blister and may occur on the face, inside the mouth, or on the hands, feet, chest or genitals.
This presentation is a bit different from previous strains of monkeypox which typically start with a fever and swollen lymph nodes before the rash develops. With the currently circulating strain, it is possible to develop one or a few lesions without any other symptoms.
How is it spread?
Monkeypox is spread by direct contact with the rash, body fluids, or scabs from lesions, including touching the contaminated linens or clothes of an infected person. Close, prolonged, face-to-face contact with respiratory secretions (saliva) via kissing or sexual contact can also transmit virus. Lesions should be considered contagious until a new layer of skin has grown over the area.
How serious is monkeypox, and are there treatments?
The West Africa clade, which the current strain belongs to, is less severe than the Congo Basin clade. It is rarely life-threatening (<1%). The WHO reports that one death has occurred out of 3413 cases reported by 50 member countries between January 1 and June 22, 2022. Most people have had a mild course of illness not requiring treatment. The lesions should be monitored for secondary infection, and rarely medical attention is needed for more severe disease, such as pneumonia or sepsis.
People who may require more careful monitoring for serious illness include those who are immunocompromised due to HIV, leukemia, lymphoma, cancer, solid organ transplant, atopic dermatitis, or those undergoing radiation, receiving TNF inhibitors, high-dose corticosteroids or a stem cell transplant. Pregnant women and children younger than 8 years may also have a higher risk of more serious disease.
There are several antiviral treatments which are known to be effective for smallpox and laboratory evidence suggests effectiveness against monkeypox as well. These drugs are available as “compassionate use” therapy for those needing more aggressive treatment.
More doses of vaccine will be distributed throughout the summer and fall with a combined distribution of 1.6 million doses by the end of the year. The expanded testing capacity will increase access to tests and make results available more quickly. This will allow for quicker contact tracing and vaccination of those with a known exposure. Finally, the administration is working with leaders in the LGBTQI+ community to reduce the stigma around testing and diagnosis, thereby increasing access to care.
Use of JYNNEOS (Smallpox and Monkeypox Vaccine, Live, Nonreplicating) for Preexposure Vaccination of Persons at Risk for Occupational Exposure to Orthopoxviruses: Recommendations of the Advisory Committee on Immunization Practices — United States, 2022 | MMWR (cdc.gov)