How to Protect Pregnant Women From the Flu

Doug Jordan, MA; Sonja Rasmussen, MD, MS


October 09, 2014

Editorial Collaboration

Medscape &

Editor's note: What have we learned since the 2009 flu pandemic? That's the focus of a new commentary from CDC experts Sonja Rasmussen, MD, MS, and Denise J. Jamieson, MD, MPH, published October 9th in the New England Journal of Medicine. In the commentary, "2009 H1N1 Influenza and Pregnancy – 5 Years Later," the authors note that during the 2009 pandemic, pregnant women were at substantially higher risk for hospitalization than the general population, and they accounted for approximately 5% of flu-related deaths reported to the CDC.[1]

Dr Rasmussen, acting director of CDC's Office of Public Health Preparedness and Response, recently spoke with Doug Jordan, MS, CDC Health Communications specialist, about what clinicians can do now to keep pregnant women safe from influenza.

Mr Jordan: What was your motivation for doing this commentary, and what should pregnant women know about the dangers posed by influenza?

Sonja Rasmussen, MD, MS

Dr Rasmussen: Since the 2009 H1N1 pandemic, we have learned a lot about influenza and pregnancy. The results of many studies have provided evidence on the impact of influenza on pregnant women, the benefits of treatment with oseltamivir, the safety of the influenza vaccine, and the steps clinicians can take to increase vaccination rates among pregnant women. We know much more now than we did 5 years ago about how to keep women and their infants safe from influenza. Yet, last year, we heard reports of severe illness, hospitalization, and death among pregnant women, sadly reminiscent of calls we received during the 2009 H1N1 pandemic. The idea for this commentary was in response to those reports. My coauthor, Dr Denise Jamieson, and I wanted to take what we now know about flu and pregnant women and make sure that information was in the hands of the clinicians who care for these women.

Mr Jordan: What are the most common misconceptions that pregnant women might have about the influenza vaccine?

Dr Rasmussen: We find that pregnant women do not always know that they are at higher risk of developing influenza-related complications. In fact, changes in the immune system, heart, and lungs during pregnancy make pregnant women more prone to severe illness, hospitalization, and even death from influenza. Infants born to women severely ill with influenza also have an increased risk for adverse birth outcomes, including preterm birth and small size for gestational age.

We also find that pregnant women often are unaware of the benefits of influenza vaccination for their baby. Flu shots during pregnancy protect not only the pregnant woman, but also her unborn baby and even her infant during the first 6 months of life. Studies have also shown that vaccinating the mother during pregnancy may reduce the occurrence of adverse outcomes like small size for gestational age and preterm birth in infants.

Mr Jordan: What do you anticipate this season in terms of flu activity and severity?

Dr Rasmussen: We can't predict what kind of influenza season we will experience in the United States this year. Every flu season is different, and influenza infection can affect people differently. Similarly, we cannot know which viruses will circulate over the season. Influenza viruses can change from one season to the next or they can even change within the course of the same season. But we know that influenza vaccination during pregnancy can reduce the risk for influenza in the mother and her baby. And we know that pregnant women suspected of having influenza should receive prompt antiviral treatment, regardless of risk factors, severity of illness, history, or diagnostic testing.

Mr Jordan: Which flu viruses does this season's vaccine protect against?

Dr Rasmussen: For the 2014-2015 flu season, trivalent influenza vaccines are made to protect against three influenza viruses: two influenza A viruses (H1N1 and H3N2) and an influenza B virus. In addition, the quadrivalent influenza vaccines, which are made to protect against four flu viruses, protect against the same viruses, and an additional B virus, as the trivalent vaccine. Yearly seasonal influenza vaccination is the best way to prevent influenza.

Mr Jordan: What are the current influenza vaccine recommendations during pregnancy?

Dr Rasmussen: CDC recommends that everyone 6 months of age or older get vaccinated against influenza each year. Getting an influenza vaccination is the best way to prevent influenza infection. Inactivated influenza vaccine is safe for pregnant women and can be administered during any trimester. Live attenuated influenza vaccine (LAIV) is not recommended for use during pregnancy. Postpartum women can receive either LAIV or inactivated flu vaccine.

Mr Jordan: What are some important points to remember when educating pregnant women about influenza vaccine safety?

Dr Rasmussen: Recommendations from healthcare providers are a critical motivator for pregnant women to be vaccinated. Clinicians should remind pregnant women of their increased risk of developing influenza-related complications, and emphasize that influenza vaccination is safe for pregnant women and has been recommended for many years by both the Advisory Committee on Immunization Practices and the American College of Obstetricians and Gynecologists. Influenza vaccination is the best way to prevent influenza and influenza-related complications like hospitalization and death in pregnant women and their babies.

Mr Jordan: What is the best way to raise influenza vaccination rates among pregnant patients?

Dr Rasmussen: Influenza vaccination benefits the pregnant mother, the unborn child, and even the baby after birth, and we know that pregnant women are motivated to do what they can to ensure the health of their baby. When they learn that influenza vaccination can benefit their child before and after birth, they are more likely to get vaccinated. Clinicians play a vital role in sharing this information.

We also know that the best way to increase influenza vaccination rates in pregnant women is by recommending the influenza vaccine and offering it in your office. Women who reported that their doctor recommended and offered the vaccine were much more likely to get vaccinated than women whose doctors recommended the vaccine but did not offer the vaccine in their office.

Mr Jordan: What treatment options are available for pregnant women with confirmed influenza?

Dr Rasmussen: Pregnant women with confirmed or suspected influenza should be treated with oseltamivir as soon as possible, and they can be treated during any trimester. Your decision to treat should be based on clinical evaluation rather than on diagnostic testing because of the limited sensitivity of rapid influenza diagnostic tests and the time required to complete more definitive testing. If a pregnant patient is exhibiting the signs and symptoms of influenza, treatment should be started. Ideally, influenza antiviral treatment should begin less than 48 hours after onset of symptoms. However, there is still clinical benefit when treatment is started in a pregnant woman who is ill with influenza, even if 48 hours have already passed. There is no "48-hour rule" that prohibits later treatment.

Mr Jordan: What else can pregnant women do to protect themselves and their families from flu?

Dr Rasmussen: In addition to getting vaccinated, pregnant women should take everyday preventive actions against influenza, like avoiding close contact with sick people, staying home if they are sick, and washing their hands often with soap and water.

It is also important to emphasize that family members and caregivers should get vaccinated. Infants can benefit from added protection when everyone who cares for them gets an influenza vaccine. This includes all members of the household, relatives, and childcare providers.

Again, clinicians play a critical role in ensuring that pregnant women and their babies are protected from influenza. By educating women about vaccine safety and the benefits of influenza vaccine, and by offering the influenza vaccine in your office, you can help to ensure that your patients and their loved ones stay safe from influenza this season.

Related Resources

CDC: Seasonal Flu Vaccine Safety and Pregnant Women

Medscape: Influenza Resource Center


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