Monkeypox: Is It an Issue for Pregnancy?

If you’re up on the health news, or even just the regular news, you probably have heard of monkeypox, a very scary-sounding disease, an even scary-looking disease, if you have seen the pictures of people who have come down with it. Monkeypox is not a pandemic, nor do public health experts expect that it will become a pandemic. We’ll cover some of the reasons for that below. Nor have there been any major stories about this disease in connection with pregnancy, but we’re discussing it today in anticipation that there will be such stories fairly soon. But though it’s not a pandemic, there have been outbreaks of monkeypox and in countries outside of Africa (where monkeypox historically has affected humans), including in the United Kingdom and the United States. Generally, so far, the main victims have been men who have sex with other men (homosexual and bisexual males and trans). This doesn’t mean necessarily that things will stay this way, but that has been the case so far.

So what actually is monkeypox? You may be wondering if it is like chickenpox and, to a certain extent, it is because in both diseases skin lesions are a prominent feature. But monkeypox is more like cowpox and like smallpox, a disease that has been eradicated. All of these diseases are caused by DNA viruses, viruses that carry DNA as genetic material, but viruses that cause monkeypox, cowpox, and smallpox, belong more specifically to a subgroup of DNA viruses called orthopoxviruses. Consequently, people who have been vaccinated against smallpox have some amount of protection against monkeypox. Health experts don’t know yet how much protection that is, but they have found that the outbreaks are occurring generally in people between the ages of 20 and 50 years. This matches up with the fact that most people who have been vaccinated against the smallpox virus, variola, are 50 years old, or older. This is because smallpox vaccination was discontinued once the disease was declared eradicated in the 1970s. There are people who were babies in certain parts of the world were small vaccination continued a few years more into the 1970s compared with the western world, so there are some vaccinated people in their late 40s. There also are younger adults who received smallpox vaccines in the military as a precaution against variola being revived as some kind of biological weapon.

Putting all of this together, most women who are currently pregnant, as well as women likely to become pregnant, are too young to have received a smallpox vaccine. And this is the only factor that puts women of reproductive age at risk of monkeypox. As of today (May 23, 2022), there have been just a handful of confirmed monkeypox cases in the United States and somewhere in the range of 100 cases in 14 countries where the disease has been reported to have spread. What has concerned authorities is the fact that, while usually monkeypox spreads from non-human animals, notably rodents, to humans, the current outbreaks seem to involve human-to-human spread.

Compared with COVID-19, monkeypox is much less contagious, plus, unlike SARS-CoV2 (the virus that causes COVID-19), the monkeypox virus appears to spread only after a person has developed symptoms. The symptoms may include fever, headache, and other such general symptoms of infection, but the disease develops to a stage characterized by very large sores on the skin, generally in the limbs, but they can also be on the face and near the eyes and can cause eye damage.

What we can say about monkeypox and pregnancy derives from what we know historically about smallpox in pregnant women and from a very small sample of pregnant women with monkeypox in Africa several years ago whose cases were part of a published paper. Specifically, there was a article in the medical literature published in 2017, describing four pregnant women in the Republic of Congo afflicted with monkeypox. Of these four women, one delivered a healthy infant, but one ended in fetal death late in pregnancy, while the other two suffered spontaneous abortions, miscarriages in the earlier part of pregnancy. In the case of the late fetal death, the fetus was found to been infected with pox soars on the limbs, trunk, and face.

Four cases are not enough to draw any scientific conclusions regarding the level of risk, but historical studies of smallpox in pregnancy have reported 34 percent of pregnant women with smallpox dying and roughly 40 percent of smallpox pregnancies ending in miscarriage or preterm birth. Based on such studies, we can anticipate that it would be extremely dangerous for monkeypox to occur in a pregnant woman, even though the case fatality rate (the fraction of cases ending in death) is much lower for monkeypox compared with what smallpox was prior to its eradication.

Although smallpox vaccination is no longer offered, health authorities are discussing the possibility of administering smallpox vaccine should the situation change and warrant such a response. Since the smallpox vaccine is a live vaccine, it would not be offered to pregnant women. However, the vaccine would not be contraindicated in a young woman who is not yet pregnant.

Most likely, there will be no need to start a vaccination campaign because, fortunately, monkeypox does not seem to spread very fast, nor is it likely to produce variants even close to how quickly SARS-CoV2 produces them. This may be due to the fact that the monkeypox virus is a DNA virus, as it is much more difficult for DNA to change that way than RNA (the genetic material in SARS-CoV2) changes.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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