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A monkeypox virion obtained from a clinical sample associated with the 2003 prairie dog outbreak. Courtesy CDC.

CDC updates monkeypox case count, provides guidance for clinicians

May 23, 2022

Health officials are investigating four possible monkeypox cases in the U.S. in addition to one that’s been confirmed and asking clinicians to be vigilant for patients who may be infected.

“I don’t think that there’s great risk to the general community from monkeypox right now in the United States,” said Jennifer McQuiston, D.V.M., M.S., deputy director of the Division of High Consequence Pathogens and Pathology at the Centers for Disease Control and Prevention (CDC). “I think we need to pay close attention to the communities in which this might be circulating so that we can communicate effectively with them and help bring this outbreak under control.”

The four cases under investigation have been confirmed to have an orthopoxvirus but are awaiting test results to show if that virus is monkeypox. They are in New York, Florida and Utah (two cases), while the confirmed case is in Massachusetts, according to the CDC. All are among men who have traveled outside the country. The CDC is closely monitoring the cases and working with states to alert close contacts to try to limit the spread. Massachusetts is tracking over 200 contacts of its resident who tested positive on May 18, the majority of whom are health care workers.

Monkeypox is endemic in West African and Central African countries, but in recent weeks, clusters have been reported in North America and Europe. As of May 21, there were 92 laboratory-confirmed cases and 29 suspected cases reported to the World Health Organization from countries where the virus is not endemic. Many of the cases have been among men who have sex with men, and experts have not established travel links to an endemic area.

AAP Red Book Editor David W. Kimberlin, M.D., FAAP, said the cases currently don’t merit any change in day-to-day practice for pediatricians.

“This is more be aware, be mindful and if you’re thinking about chickenpox, you probably should be thinking about monkeypox with where we are right now,” he said. “If you have someone who has contact with someone that might have had monkeypox, obviously then you’re going to be thinking about it.”

The CDC and Dr. Kimberlin provided the following information for clinicians on monkeypox symptoms, transmission, treatments, vaccines and steps to take in a suspected case.


Monkeypox always involves a characteristic rash. Unlike chickenpox lesions, all monkeypox lesions will be at the same stage of development. They will go from flat macules to papules to vesicles that rapidly turn into pustules, according to Dr. Kimberlin. The hard white pustular nodules are deeper in the dermis of the skin than chickenpox. In some recent cases, the rash has appeared in the anal or genital regions and can be mistaken for a sexually transmitted infection.

Monkeypox patients also may have a fever and swollen lymph nodes, which often begin before the rash. The incubation period usually is 7-14 days but can range from 5-21 days, according to the CDC.

Children, pregnant women and people who are immunocompromised are at risk of more severe disease, according to Dr. Kimberlin. CDC experts said people with certain skin conditions like atopic dermatitis or eczema also may be at higher risk.


Lesions carry the most virus, CDC experts said. A person is considered infectious from symptom onset until the lesions have crusted. People can become infected from direct contact with the lesion, bodily fluids or lesion material. While monkeypox is not a sexually transmitted infection, it can be transmitted during sexual contact or shared bedding or clothing. People also can transmit the virus through respiratory droplets from prolonged close contact, typically within 6 feet for at least three hours.

“It’s not a situation where if you’re passing someone in the grocery store, you’re going to be at risk for monkeypox,” Dr. McQuiston said.

She said the primary risk is to family members of an infected person and health care workers.


The U.S. cases have been from the West African strain of the virus, which is the milder of the two, according to the CDC. Most people recover in two to four weeks without specific treatment.

Two antivirals, tecovirimat and brincidofovir, have been approved for use against smallpox and potentially could be used to treat monkeypox. The CDC is working on developing treatment guidance and procuring doses.


Two vaccines can be given to people who may have had contact with a monkeypox patient. JYNNEOS is a two-dose vaccine approved for smallpox and monkeypox in adults at high risk of infection. There are 1,000 doses in the strategic national stockpile, and the CDC is working to procure more. It has more than 100 million doses of ACAM2000, but this older vaccine has more side effects.

“I think right now we are hoping to maximize vaccine distribution to those that we know would benefit from it,” Dr. McQuiston said. “Those are people who have had contact with a known monkeypox patient, health care workers, very close personal contacts and those in particular who might be at high risk for severe disease.”

Guidance for clinicians and the public

In a recent health advisory, the CDC advised clinicians to watch for patients with the characteristic monkeypox rash and symptoms. They should have heightened suspicion if these patients are men who have sex with men and present with lesions in the genital/perianal area as well as for people who recently traveled to a country with cases and people who have had contact with suspected or confirmed monkeypox patients.

They should consult their state health department if they suspect monkeypox. Laboratory Response Network labs are testing for orthopoxvirus, and the CDC is testing confirmed specimens for monkeypox. The CDC will hold a webinar for clinicians at 2 p.m. ET on May 24.

People who develop symptoms should contact their health care provider. However, Dr. Kimberlin said the risk for the general public in the U.S. is “very very very low,” and not a cause for concern.

“It is not anywhere near as infectious or contagious as COVID,” he said. “I think right now part of the reason probably we as a country and the world are more nervous about monkeypox is because of what we’ve been through these last two and a half years. But this is not the same virus as COVID. Not only literally is it not the same virus, but it behaves quite differently than the COVID virus.”



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