Dr. deHoop / Kalispell OB/GYN


I am 36 weeks pregnant and my doctor recommended that I get the flu vaccine as well as the vaccine for pertussis (Tdap).  I remember the recommendation of the flu vaccine with my previous child, but not the Tdap.  Why are these vaccines important in pregnancy?


This is a very important question and also timely as we are about to enter the peak season for flu, which can last from October to May but peaks in December to February.  While everybody is at risk of contracting the respiratory virus, certain groups are more susceptible to the severe illnesses associated with flu, such as pneumonia.  Pregnant women belong to that high-risk group which also includes infants and young children, the elderly and those with certain health conditions.  While many may have the typical symptoms of fever, chills, sore throat, muscle aches and fatigue, the death-rate from the flu and associated pneumonia has ranged from 3,000 to 48,000 in the US over the past 30 years.

The flu virus mutates into several new strains each year, requiring a new vaccination each year to the most common strains determined to affect the US.  Pregnant women should only be vaccinated with the inactivated vaccine which is given as an injection; the nasal vaccine should not be used during pregnancy.  Vaccines without the preservative thimerosol are available, although multiple studies of thousands of women vaccinated with vaccines containing small amounts of thimerosol have demonstrated its safety.

Vaccination of expectant mothers not only offers them protection, but studies have shown that infants whose mothers have been immunized have demonstrated fewer laboratory-confirmed cases of influenza as well as fewer cases of respiratory illness with fever.   If the mother is immunized, an infant still in the womb can acquire protective antibodies from her in a process called passive immunity.   This is the best prevention strategy since newborns are unable to receive the vaccination until 6 months of age.

Vaccination for pertussis (with Tdap) in pregnancy is a newer recommendation.  Pertussis or Whooping Cough is another respiratory virus that leads to prolonged coughing spells and can develop into pneumonia in infants and young children.  Before the advent of a pertussis vaccine in the 1940s, it was a devastating illness with high infant mortality.  Vaccinations were responsible for a decrease in the pertussis infection from about 250,000 cases in 1934 to just over a 1,000 in 1976. Since 1976, there has been an increase in the incidence with over 41,000 cases reported in 2012.   Infants and young children represent the population most at risk for severe complications from pertussis.  The emphasis to protect newborns is based on the fact that almost 70% of them are hospitalized when infected and 1.6% of those infected die.

Since newborns don’t start their series of vaccines until 2 months of age and aren’t likely to be protected for several more months, the CDC (Centers for Disease Control and Prevention) in 2006 recommended that anyone who could be in contact newborns be adequately vaccinated against pertussis to reduce the risk of transmission.  In the face of dramatic and persistent increases in the incidence of pertussis in the US, the CDC determined it was inadequate for the infant to rely solely on the immunity of those around them for pertussis protection in the critical first 2-3 months of life until they can be vaccinated.  In February 2013, the CDC recommended that all pregnant women receive the Tdap vaccine regardless of prior vaccinations, in order to maximize the antibody response in the mother and provide immediate postpartum protection for the newborn after delivery.  Passive immunity is optimal when the vaccine is given between 27 to 36 weeks pregnancy, but no less than a week before delivery.  It can be given earlier if necessary, for example if a local outbreak exposes the mother earlier in her pregnancy.

As with the flu vaccine, there is no evidence of adverse effects on the child from vaccinating a pregnant woman.  As with any vaccine, it should not be given if she has had a life-threatening allergic reaction to a vaccine or has a severe allergy to any part of the vaccine.  Any woman who has a nervous system disorder, has ever had Guillain-Barre Syndrome or isn’t feeling well on the day the shot is to be administered, should talk to their doctor.

Finally, those coming into close contact with your baby should be up-to-date on their vaccines.  This is especially true for the yearly influenza vaccine and the pertussis booster.

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Dr. deHoopDr. deHoop is a regular contributor to 406 Woman Magazine.  Dr. deHoop has been writing, publishing and lecturing about the female athlete for almost two decades. 

This article  appears in the  February/March 2014 addition online and in print version around the Flathead Valley.

PLEASE NOTEThis information is not intended to be medical advice.  It is general health information and does not take into account your particular health status nor is it a substitute for personal medical care.  Kalispell OB/GYN shall not be liable for any damages arising out of the use of the content herein.