May 26 2022

Our Experts Help Explain the Monkeypox Outbreak

As of May 25, there are 226 confirmed cases of monkeypox in 21 countries—the largest monkeypox outbreak to date and the first instance of widespread community transmission outside of Africa. Among these are several confirmed cases in the United States.

Monkeypox virus, a virus in the same family as smallpox, was first identified in 1958 in laboratory monkeys in Denmark. The natural animal reservoir for the virus is actually in rodents. The first cases in humans were found in the Democratic Republic of Congo (DRC) in 1970. Since then, there have been several outbreaks, including one in 2003 in the United States traced to an Illinois pet store that imported rodents from Ghana.

Symptoms begin with fever, headache, muscle pains, swollen lymph nodes, and fatigue. This is followed by a rash that forms blisters and crusts over. The time from exposure to onset of symptoms is usually 7 to 14 days. The duration of symptoms is typically two to four weeks.

Transmission reached out to Columbia Mailman School epidemiologists for their insights. Wafaa El-Sadr is director of ICAP at Columbia; Ian Lipkin is director of the Center for Infection and Immunity has worked on responding monkeypox outbreaks in Liberia and the DRC going back more than a decade; Stephen Morse is a leading authority on emerging infectious diseases. The bottom line: monkeypox is preventable, treatable, and there is very little risk of infection.

How concerning is this outbreak?

Waffa El-Sadr: The monkeypox outbreak is of concern, but should not cause panic at this moment in time. The reason for concern is that to date this outbreak has been quite widespread, with cases reported from several countries where this infection is not endemic. 

Steve Morse: This isn’t likely to come anywhere near the SARS-CoV-2/COVID-19 pandemic. Monkeypox can transmit to some degree, but not like our current pandemic. But it should remind us to be watchful and never allow ourselves to lapse into complacency. The microbial world is still full of surprises. 

Ian Lipkin: Infection has been fatal in people with HIV/AIDS but is not typically a cause of serious systemic illness. It is nonetheless capable of causing serious morbidity in people who are otherwise healthy. Blindness can occur if the infection involves the eyes. Infection can also cause scarring and changes in skin pigmentation. Smallpox vaccination should be protective; however, vaccination in the US was discontinued in 1971; thus, the majority of the U.S. population is not immunized against poxviruses.

Do we know why the current outbreak is bigger than the previous ones? 

El-Sadr: There is no evidence that the monkeyvirus strain causing this outbreak is any different from the known strains.  It is possible that with easing of restrictions and rebound in travel and socializing, this may have facilitated wider transmission of this virus. 

Morse: Many (not all) of the cases are in men who have sex with men (MSM), and lesions can occur on different places on the body, including the genitals or mouth.  Much of the spread is probably through the social contact networks of MSM (similar to the early spread of HIV), by contact with lesions or contaminated shared items. 

Lipkin: The recent outbreaks occurred in the context of large gatherings associated with promiscuity and sex toys that may themselves become contaminated with infectious virus. It’s not a sexually transmitted disease, but it is spread through intimate contact. The virus is known to persist on objects and surfaces.

What options do public health officials have to address this outbreak?

Morse: We have a new smallpox vaccine; many Western countries (including the U.S.) should have stockpiles or supplies. The vaccine used for smallpox is also very protective against monkeypox, and can prevent disease if given to an exposed (potentially infected) person, often even if given within a week or more after infection. For later stages, there are also a few therapeutics now, although we think most people won’t need that much medical intervention. Some of the patients are being kept in hospitals mostly to prevent further spread and to observe in case they do need more care.  

El-Sadr: This outbreak highlights again the value of fundamental public health work. Communicating clearly and often regarding the outbreak to providers and the public is very important in order to promptly identify suspected cases and contacts. Meticulous interviewing of cases is what public health workers know how to do best, working diligently at identifying risk factors and possible sources of infection. Lastly, getting cases of this rare virus diagnosed as quickly as possible means mobilizing diagnostic capacity at public health and other laboratories.

Lipkin: The message should be: promiscuity, particularly with people you don’t know well is risky. At the same time, it’s important that we should push back against prejudice against men who have sex with men.

As individuals, what can we do to protect ourselves?

El-Sadr: It’s important to avoid close contact with someone who is showing any of the symptoms suggestive of this infection. If you encounter someone who has travelled from endemic areas of the world, or has had contact with such an individual and who has symptoms of monkeyvirus infection, please urge such a person to seek care as soon as possible. What we have learned again and again is that viruses do not discriminate, and neither should we. We have to avoid stigmatizing men who have sex with men or are bisexual or those from the African continent, they are not the only people at risk. Let us not repeat the errors of the past.

Lipkin: Infection can occur without sex; nonetheless, sex as a common feature in intimate contact increases risk. At present, the risk has been highest in men who have sex with men.

Morse: There appears to be little, if any, respiratory transmission, so there will be almost no risk for most people. If you’re still using the SARS-CoV-2/COVID-19 precautions, you’re probably more than safe on that score already.  Keep up on current information from CDC or your health department. Avoid close contact with anyone who has unusual skin lesions or lymphadenopathy (lymph node enlargement, which may precede the skin lesions), or anyone who thinks they were exposed, and see your doctor right away. Likewise, if you have any of these symptoms.  Although we are still evaluating the data, what we know from past experience with the West African monkeypox is that most of us are at very low risk.

June 15 Update: For more on monkeypox, read an article on VeryWellHealth.