Mixed Messages May Prevent Pregnant and Lactating Women from Getting Flu Shots

Researchers in a recent study investigated how mixed messages delivered by vaccine manufacturers may prevent women from receiving the safe and effective influenza vaccine during pregnancy.

During pregnancy, expectant mothers have to make many choices regarding their health and the health of their babies, and among theses choices is whether or not to receive the flu shot. Researchers in a recent study investigated how mixed messages delivered by vaccine manufacturers may prevent women from receiving the safe and effective influenza vaccine during pregnancy.

As flu season in North America is fast approaching, pregnant women will have to make the important decision about whether or not to receive the flu vaccine. A group of researchers from the Johns Hopkins Bloomberg School of Public Health in Baltimore and the World Health Organization (WHO), recently wrote a study published in the medical journal, Vaccine. In their study, they examined how information from flu shot manufacturers has, at times, failed to reflect the recommendations of world health officials, thereby causing pregnant and lactating women to turn down the influenza vaccine that can provide protection to an expectant mother and her baby. “Misperceptions and lack of awareness regarding influenza vaccine efficacy and safety have been identified as barriers to vaccination among health care providers,” note the study’s authors.

According to the Centers for Disease Control and Prevention (CDC), the flu is more likely to cause severe illness in pregnant women than in healthy women who are not pregnant, and can cause pregnancy complications that may result in premature labor and delivery. WHO explain that, “vaccine-preventable infectious diseases are responsible for significant maternal, neonatal, and young infant morbidity and mortality.” A woman’s immune system undergoes changes during pregnancy, which may make her more susceptible to infectious diseases and put her at increased risk of these diseases resulting in serious health implications. Health experts around the world support vaccines such as the flu shot for pregnant women, who can pass their immunity on to their unborn children. Immunizations can be an important part of a healthy pregnancy and may bolster a newborn’s resistance to infections in their first months of life.

While millions of pregnant women have safely received flu shots over the years, with scientific studies supporting the safety and efficacy of these vaccinations, the authors of the recent study aimed to identify barriers to influenza vaccine uptake in women who are pregnant. They looked at the language used by vaccine manufacturers in their product information, which is “formulated based on precautionary principles by regulators and pharmaceutical companies.” When vaccine manufacturers use language that comes across as “overly cautionary or restrictive” regarding the use of the vaccine by pregnant and lactating women, language can serve as an obstacle to these women considering getting the flu shot.

The researchers studied the product information language for 96 influenza vaccines marketed in different countries, using the most recent examples for seasonal, pandemic and pre-pandemic influenza vaccines, and found mixed messages regarding use in pregnant and lactating women.

Of the vaccines studied, only ten included product information that suggested use during pregnancy: one from Australia, one from Canada, one from East Asia, and the remaining seven were from European Union countries. Of those, there was a wide variety of information regarding safety data for pregnancy. One vaccine’s information read that influenza vaccines can be used throughout pregnancy. Seven stated that inactivated influenza vaccines can be used throughout all stages of pregnancy and that safety data hasn’t shown any adverse events that could be attributed to the vaccine in pregnant women or their fetuses. Adding to the inconsistency, product information from another vaccine recommended influenza vaccine ‘‘to pregnant women who will be in the second or third trimester during the influenza season, including those in the first trimester at the time of vaccination” and further indicated that the vaccine has not been evaluated in pregnant women.

Of the rest of the vaccines’ product information studied, 20 used language that suggested that official recommendations should be considered when it comes to pregnant women use. Another 48 of the vaccines had product information with language suggesting that users consult a health care provider to determine whether the vaccine should be administered during pregnancy. More than a quarter of the vaccines came with information suggesting use ‘‘if clearly needed” without further explanation of ‘‘clearly needed.” Two vaccines contained information recommending that a healthcare provider assess the situation and also noted that people at increased risk should receive the vaccine at any stage of pregnancy.

“Despite the favorable risk-benefit profile for influenza vaccination of pregnant and lactating women recommended by WHO, many governments, obstetricians, and expert groups, product information for some vaccines limit or even contraindicate the use of influenza vaccines in pregnant women,” write the study’s authors. “Further studies are indicated to determine the factors that contribute to low immunization coverage rates in pregnant women, including understanding by healthcare providers of the benefits to the mother, the developing fetus, and the infant in the first few months after birth. The evidence resulting from such studies could help inform and optimize educational interventions targeting health care workers recommending or giving influenza vaccines to pregnant women.”

The CDC recommends that pregnant women, at any stage of pregnancy, receive a flu shot to protect themselves as well as their babies from infection. The flu shot has not been shown to cause harm to pregnant women or their babies. According to the CDC, possible side effects can include:

  • Soreness, redness, and/or swelling from the shot
  • Fainting
  • Headache
  • Fever
  • Muscle aches
  • Nausea
  • Fatigue