19 Oct The Flu is Coming!
As the temperatures drop and the days get shorter, that only means one thing: winter, along with flu season, is creeping up. As a pregnant woman, you may be asking yourself, should I get a flu shot? Is it safe for my baby? The answer is yes, especially as it is even more important as a pregnant woman to get a flu shot. The CDC reports that it is safe, and recommended, for pregnant women to be immunized and that there is no increased risk for miscarriage.1
In addition to protecting yourself and your newborn baby from contracting the flu, there are other long-lasting reasons to get vaccinated. There is a clear link between maternal influenza exposure and increased child risk for bipolar disorder, schizophrenia, and even autism.2-6 Some research has linked flu exposure to a nearly six-fold increase in a subtype of bipolar disorder with psychotic features.2 Other studies have found a threefold increased risk for schizophrenia associated with maternal influenza during the first half of pregnancy.2,4 Some data suggests that up to 14% of schizophrenia cases would not have occurred if influenza exposure during early to mid pregnancy had been prevented.4 Furthermore, autism has previously been linked to first trimester maternal viral infections and fever during pregnancy.2,6 Inflammatory cytokines that are activated when the maternal adaptive immune system is challenged with a virus release prostaglandins that initiate fever. These cytokines have the potential to cross the placenta and influence fetal development, potentially inducing behavioral abnormalities that are associated with autistic or schizophrenic behaviors.6,7 Therefore, it is important to note that the increased risk of neurodevelopmental disorders associated with influenza and other viral infections may be due to the immune reaction of the mother, not the virus/infectious agent itself.8
The CDC recommends that pregnant women get a flu shot during any trimester of their pregnancy to protect themselves and their newborn babies from flu.9 However, it may be advantageous to get one earlier during pregnancy, if possible, to help limit other lasting risks. The CDC recommends getting a flu shot in the fall, and suggests the best time is before the end of October (AKA now!!).9 The activity and virulence of the influenza virus typically peaks in December and January, and since it takes about two weeks for the body to produce antibodies against the influenza virus, it is important to get vaccinated early.9 It is important to note that the nasal spray vaccine (live attenuated influenza vaccine (LAIV)) is not recommended for use due to concerns about effectiveness.9 The CDC recommends use of the flu shot (inactivated influenza vaccine or IIV) or the recombinant influenza vaccine (RIV).9
There are multiple influenza viruses that are continually adapting and evolving to changing environmental conditions. It is important to develop annual flu vaccines that match the strains that are circulating at that time. Flu vaccines protect against the three or four viruses (depending on vaccine) that research suggests will be most common for that year.9 This is why you need a flu shot every year.
For the 2017-2018 flu season, the three component vaccines are recommended to contain:
• A/Michigan/45/2015 (H1N1)pdm09-like virus (updated)9
• A/Hong Kong/4801/2014 (H3N2)-like virus9
• B/Brisbane/60/2008-like (B/Victoria lineage) virus9
The four component vaccines protect against a second lineage of B viruses. They are recommended to contain the same viruses recommended for the trivalent vaccines, as well as:
• B/Phuket/3073/2013-like (B/Yamagata lineage) virus9
So, this flu season remember to protect yourself, and your developing baby, from potentially harmful risks and get vaccinated! The process is quick and (mostly) painless. Not only will you have peace of mind, but you will avoid those nasty sick days laying on the couch and slurping soup. Pregnancy can be hard enough, don’t make it harder on yourself by getting the flu!
References: 1. Flu Vaccine Safety and Pregnancy. Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (NCIRD). Page last reviewed: September 19, 2017. Page last updated: October 3, 2017. Website. https://www.cdc.gov/flu/protect/vaccine/qa_vacpregnant.htm. 2. Flu in Pregnancy May Quadruple Child’s Risk for Bipolar Disorder. National Institute of Mental Health. Press Release. May 2013. Website. https://www.nimh.nih.gov/news/science-news/2013/flu-in-pregnancy-may-quadruple-childs-risk-for-bipolar-disorder.shtml. 3. Gestational Influenza and bipolar Disorder in Adult Offspring. Parboosing R, Bao Y, Shen L, Schaefer CA, Brown AS. JAMA Psychiatry, May 8, 2013. 4. Warner, Jennifer. Schizophrenia Linked to Flu During Pregnancy. Reviewed by Michael W. Smith, MD on August 02, 2004. Website. https://www.webmd.com/schizophrenia/news/20040802/schizophrenia-linked-flu-during-pregnancy. 5. Wright P, Takei N, Rifkin L, Murray RM. Maternal influenza, obstetric complications, and schizophrenia. Abstract. Am J Psychiatry. 1995 Dec;152(12):1714-20. PMID: 8526235 DOI: 10.1176/ajp.152.12.1714. 6. Zerbo O, Iosif A-M, Walker C, Ozonoff S, Hansen RL, Hertz-Picciotto I. Is Maternal Influenza or Fever During Pregnancy Associated with Autism or Developmental Delays? Results from the CHARGE (CHildhood Autism Risks from Genetics and Environment) Study. Journal of autism and developmental disorders. 2013;43(1):25-33. doi:10.1007/s10803-012-1540-x. 7. Smith SE, Li J, Garbett K, Mirnics K, Patterson PH. Maternal immune activation alters fetal brain development through interleukin-6. Journal of Neuroscience. 2007;27(40):10695–10702. 8. Shi L, Fatemi SH, Sidwell RW, Patterson PH. Maternal influenza infection causes marked behavioral and pharmacological changes in the offspring. Journal of Neuroscience. 2003;23(1):297–302. 9. Frequently Asked Flu Questions 2017-2018 Influenza Season. Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases (NCIRD). Page last reviewed: September 14, 2017. Page last updated: September 14, 2017. Website. https://www.cdc.gov/flu/about/season/flu-season-2017-2018.htm.