Update on What We Know About COVID-19 Infection and Treatments During Pregnancy

Note: The Pregistry website includes expert reports on more than 2000 medications, 300 diseases, and 150 common exposures during pregnancy and lactation. For the topic Coronavirus (COVID-19), go here. These expert reports are free of charge and can be saved and shared.

Over the past two and a half years, scientists and physicians have learned a great deal about about SARS-CoV2 (the virus that causes COVID-19). This includes much information about the course that the infection takes during pregnancy, the risk of the baby becoming infected with the virus, and the protection that the baby receives from maternal antibodies (antibodies generated by the mother’s immune system) before and after birth. During these two and a half years, we have reported on progress in understanding the infection during pregnancy and on the advances in clinical management, and prevention. During the first year of the pandemic, mostly 2020, there was a lot of discussion on The Pulse about questions of the nature of COVID-19 disease.

Early on, these questions included whether getting COVID-19 once could protect people against getting it a second time. Today, we know that the answer is yes, but with a very big caution. SARS-CoV2 infection with symptoms, meaning COVID-19 disease, does provide some protection, because the immune system learns to recognize the virus and mount a response to it, the virus even appears in the person’s body again. Since those early days, we have learned that, unlike dengue viruses, which cause dengue fever, SARS-CoV2 does not seem to stimulate the immune system in a way that causes worse disease the second time that a person gets infected. The scientific way to say this is that with SARS-CoV2 there does not seem to be antibody-dependent enhancement, as there is with dengue. This is important, because such an antibody enhancement would have made it much more difficult to develop vaccines against SARS-CoV2. But we have also learned that the kind of protection that one receives from a first bout of COVID-19 is not a very strong protection. The experience of the pandemic has shown us that plenty of people can become ill with COVID-19 more than once. On the other hand, we also have learned that the combination of getting COVID-19 (or getting a SARS-CoV2 infection without symptoms), plus being vaccinated provides much better protection than having been infected and not being vaccinated.

While there is currently some uncertainty about how much protection a past infection adds to a pregnant woman who is up to date with her vaccine doses, it is clear that a pregnant woman who is fully vaccinated and has never had COVID-19 has better protection than a pregnant woman who has had COVID-19, but has never been vaccinated. There is some concern that this might change as the variants of the SARS-CoV2 virus continue to evolve. Coming soon, however, will be COVID-19 vaccine boosters that have been modified to work better against the omicron variant —whose subvariants (versions of the variant with minor differences) are the cause of most COVID-19 cases.

From the same perspective, it is also clear that, if you have had your needed vaccine doses and then you develop COVID-19 either before or after you become pregnant, you are very likely to avoid the moderate to severe COVID-19 disease that pregnant women are at elevated risk to develop when they have not been vaccinated.

While more research is still needed to know exactly how much protection a mild case of COVID-19 adds to the protection of vaccination, the confidence among doctors and researchers is high that somebody who has received the first two vaccine doses (the primary series for the Pfizer-BioNTech or Moderna vaccines, known as mRNA vaccines) and also a booster dose probably gets a good boost to her immunity if she then gets infected and develops mild COVID-19. In other words, a bout of COVID-19 may function as a kind of booster dose.

While you should be vaccinated against COVID-19 to protect you against moderate to severe disease, the various types of omicron variant are extremely infectious and its very difficult to avoid becoming infected at all. Vaccinated pregnant women who develop COVID-19 tend to develop mild cases, just like any other vaccinated people.

If you are pregnant and received any brand of a COVID-19 vaccine during pregnancy, join the COVID-19 Vaccines International Pregnancy Exposure Registry (C-VIPER). This study is sponsored by Pregistry and is the world’s largest one on COVID-19 vaccines and pregnancy.

Another difference with COVID-19 in mid-2022 compared with a year or two ago is that now there are various treatments available for mild cases. These treatments decrease the risk that the COVID-19 will worsen to a moderate or severe case. The treatments include antiviral medicine, not all of which are considered safe in pregnancy. One antiviral in particular, called molnupiravir, is not currently recommended in pregnant women but it turns out that this medicine is the least effective of the various options offered to non-hospitalized people with COVID-19. Another antiviral called remdesivir can be given to pregnant women and is fairly effective in helping to keep COVID-19 mild and shortening the disease, if given early in the course of the disease. But remdesivir is given intravenously, so you would have to go to a facility to receive it. The most effective medicine to fight the virus in mild cases is Paxlovid. If started within five days of first developing COVID-19 symptoms, Paxlovid can really help to keep the disease mild, although, as we have pointed out several times, it’s likely to stay mild anyway, if you don’t have risk factors and —we cannot emphasize this enough— if you have been vaccinated. Paxlovid is not known to be dangerous during pregnancy. There is some debate about whether it should be offered but the Society for Maternal Fetal Medicine came out in support of offering Paxlovid during pregnancy as early as last December. The treatment consists of two medicines that come as three pills that you take twice per day for five days. Whether or not you should have such a treatment depends on your particular case and risk factors.

If you are pregnant or recently pregnant and had COVID-19 during pregnancy that required medical treatment (e.g., monoclonal antibodies or an antiviral such as remdesivir or molnupiravir), join the COVID-19 International Drug Pregnancy Registry (COVID-PR). This study is sponsored by Pregistry and is the world’s largest one on medications for COVID-19 and pregnancy.

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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