Pregnant Women Benefit from Early Flu Shots

May 17, 2011
Jennifer Barrio Managing Editor

To best protect mother and baby, pharmacists should encourage pregnant women to get vaccinated against the flu early in the season.

To best protect mother and baby, pharmacists should encourage pregnant women to get vaccinated against the flu early in the season.

When it comes to getting a flu shot, earlier is definitely better for pregnant women, according to the findings of a study published online April 18, 2011, in the American Journal of Obstetrics and Gynecology.

Evan R. Myers, MD, MPH, of Duke University and colleagues used a mathematical model to examine the benefits of flu vaccination to both mother and baby at different times of the year. Their results showed that if vaccination is delayed past November, the benefits of vaccination are reduced. Women who get vaccinated within 4 weeks of the vaccine’s availability will see the most benefit, according to the study.

Flu season in the United States can start as early as October and last until May, with the peak of the season occurring between January and March. The Centers for Disease Control and Prevention (CDC) recommend that all pregnant women receive flu vaccination, because changes in the body during pregnancy can make women more vulnerable to severe complications from the flu that can result in hospitalization and even death.

If all pregnant women were vaccinated, the study estimated, one-third of influenza-related hospitalizations could be prevented, reducing the number to 1235 per year. Physicians’ office visits would also decline sharply, from approximately 54,000 visits per year to an estimated 23,000.

The study authors also emphasize that because antibodies can pass from mother to baby, the protection provided by a flu shot extends to infants, who cannot be vaccinated before 6 months of age. The study predicts that infant hospitalizations for the flu could decline from 4700 to 3000 with the comprehensive vaccination of pregnant women. Women who will give birth before the start of flu season should consider vaccination to reduce the risk of flu-related complications to their infants, Dr. Myers said.

Despite the evidence suggesting the benefits of vaccination, pharmacists will likely encounter women who are nervous about vaccination during pregnancy. Counsel pregnant women that the CDC considers the flu shot, which is made from a killed form of the virus, to be perfectly safe during pregnancy. Pregnant women should not receive the nasal spray formulation of the flu vaccine, however, because it contains live virus.

Multidose formulations of the flu shot contain thimerosal, a mercury-containing preservative, which may also be a concern for some pregnant women. Thimerosal has been the center of a debate concerning its possible connection to childhood neurodevelopmental disorders, including autism. For patients for whom thimerosal is deterent from receiving a flu shot, pharmacists can offer single-dose, thimerosal-free formulations of the vaccine.

For other articles in this issue, see:

  • Medicare Funds to Run Out by 2024
  • Helping Heart Patients Streamline Drug Routines