Why Pregnant Women Must get the Flu Shot in the COVID-19 Era

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Back in April, we discussed why COVID-19 is worse than the seasonal influenza, whether or not you are pregnant, but, rather than rendering influenza immunization moot, COVID-19 makes it all the more important that you get a flu shot for the upcoming 2020-2021 season. That’s because, while clinical management of COVID-19 is improving, such that survival is going up gradually (the death rate is going down), the combination COVID-19 and flu in a patient carries a gloomy prognosis. Thus, if you do become infected with SARS-CoV2 (the virus that causes COVID-19), you’re in a far better situation than someone with SARS-CoV2 plus one or more flu viruses.

Now, when we say that seasonal influenza is more manageable than COVID-19, of course we are not talking about unusual forms of the flu that emerge occasionally as pandemics as bad, or worse than COVID-19. An extreme example is the 1918 flu pandemic, which struck an estimated 500 million people (one third of the humanity of that time period) and killed from 50 million to 100 million people. That pandemic differed from seasonal flu in a couple of major ways. First, the 1918 flu was more contagious and more deadly than the seasonal flu. Second, the 1918 flu was most deadly in young to middle age adults, a population that included pregnant women, whereas seasonal flu is most dangerous in people who are old and those who are weakened because they suffer from other medical conditions. In terms of who is at risk, COVID-19 is actually more like seasonal flu than like the 1918 flu.

There is, of course, another factor, namely that vaccines are available for seasonal flu, but, as of the summer of 2020, still months away when it comes to COVID-19. In the latter case, three vaccines showing promise are the Oxford (AstraZeneca), the Moderna, and Johnson an Johnson vaccines. This might lead the beginning of COVID-19 immunization of large amounts of people in the United Kingdom this coming autumn and a few months later elsewhere, including in the United States, depending on how clinical trials go.

Other than people who are participating as test subjects in the clinical trials, very likely, the first people to receive COVID-19 vaccines will be health care workers and others who are at risk, so in the meantime, you should do all that you can to minimize your risk. This means the risk of becoming infected with SARS-CoV2 as well as the risk of developing severe disease, if you do become infected. That means doing all that is possible to keep yourself from getting the flu –thereby complicating COVID-19– which in turn means getting your flu shot.

The effectiveness of flu vaccination is variable and less than what we want from a vaccine. This is because influenza viruses easily undergo mutations of the genes that carry instructions for making proteins that sit on their surfaces. Vaccines teach your immune system to make antibodies that attach to such proteins, and in doing so neutralize the virus. Each flu season, there are several different versions of influenza virus circulating and vaccine researchers must predict which flu viruses will dominate and create a vaccine that will work against them. While getting such a seasonal flu vaccine will not guarantee that you won’t come down with the flu, it actually does reduce your risk of catching the most serious flu viruses of the season, plus the flu shot tends to reduce the duration and severity of your disease, if you do catch the flu. Whether you are pregnant or not, by getting a flu shot, you are less likely to need hospitalization, less likely to require admission to the intensive care unit (ICU) if you do get hospitalized, and less likely to die from the flu.

Another factor to keep in mind is that COVID-19 has overwhelmed hospitals in many places, so it’s best to avoid the need to go to the hospital for other reasons, including to get treated for the flu. While there are also efforts to keep flu patients who are negative for COVID-19 separate from COVID-19 patients, flu uses the same types of hospital facilities as COVID-19 uses. It depends on internal medicine wards, and, for those who become very ill, it depends on ICUs. Additionally, if you arrive at the emergency department of a hospital with flu symptoms, you will look like a COVID-19 patient until you are tested for both COVID-19 and the flu and come out to be negative for COVID-19.

While a lot still needs to be learned about the interaction between pregnancy and COVID-19, what is very clear is that the interaction between the flu and COVID-19 is not good. Consequently, you should take all available precautions against getting the flu –social distancing (we stay away from one another, go out for only essentials, such as grocery shopping, and wear masks and gloves when doing that shopping—but you should also get your flu shot as soon as it becomes available for the upcoming season.

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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