A recent study published last Tuesday in the journal Pediatrics revealed that babies born to mothers who received flu vaccine during pregnancy had less chances, up to 64%, for influenza like illness including 70% reduction for laboratory-confirmed influenza, and 81% decrease in the incidences of influenza hospitalizations in their first six months.

The researchers from the University of Utah, US, checked hospital records for 245,386 women and 249,387 infants. The women considered in the study were those who delivered babies at Intermountain Medical Group Clinics in Utah and Idaho, during the period 2005-2014 to analyze the flu incidences. Overall, 10% pregnant women reported influenza immunization. The findings revealed three major outcomes including infant influenza-like illness (ILI), laboratory-confirmed influenza, and influenza hospitalizations.

A total of 658 infants out of the total with laboratory-confirmed influenza, 638 cases (2.83 per 1,000) were born to women who were not immunized during pregnancy, whereas, 20 (0.84 per 1,000) were born to women who reported having a flu shot while they were pregnant. The total of 151 infants were reported to be hospitalized due to flu, out of which three were born to the immunized mothers and 148 were those born to unimmunized mothers.

The assistant Pediatrics Professor Ms Julie Shakib and her colleagues characterized influenza vaccination as a public health priority and urged mothers to get immunized during pregnancy to protect their infants from the infections caused by influenza which if left untreated can even lead to deaths in infants. “Protecting young infants from influenza through maternal immunization during pregnancy is a public health priority,” she said.

In order to further validate the strength of the study and to check the extent of the immunization benefits not entirely limited to chance, the researchers investigated the incidences of another respiratory infection caused by ‘respiratory syncytial virus’ of infants that occurs during the winter season and found no association of the of this infection with the influenza immunization. According to the researchers, this finding shows that giving a flu vaccine during pregnancy leads to flu-specific benefits in baby.

The researchers also explained the aspect of immunizing mothers instead of the infants directly due to the fact that the immune response of the infants is found to be insufficient for accepting direct immunization leaving it ineffective. Therefore, indirect passive immunity is provided by immunizing mothers.

The researchers told that no violation of ethical rights of human subjects was done during the study and approval to conduct the study was granted by the institutional review boards of the University of Utah and Intermountain Healthcare in Salt Lake City, Utah.

A major flu pandemic emerging from United States was reported between 2009-2010. It was caused by H1N1 influenza virus, according to CDC records. As a result, the number of pregnant women getting influenza vaccines increased. The researchers urged pregnant women to ask for the flu vaccines, even if the doctor does not offers it.

The population based statistical analysis conducted by CDC reports the estimated number of flu-associated deaths in United States in the time period 1976-2007 ranged between 3,000 to about 49,000 people.

American healthcare authorities suggest to get vaccinated every year. The CDC’s Advisory Committee Immunization Practices (ACIP) recommends flu immunization for every individual who is six months or older. The vaccines which contain live attenuated influenza vaccine (LAIV) or inactivated influenza vaccine (IIV) can be used.

According to CDC, the traditional flu vaccines are called “trivalent” vaccines. Other flu vaccines, called “quadrivalent” viruses, are also available which enable protection against four viral strains.

These vaccines provide protection against three major flu viruses including:

  • An influenza A (H1N1) virus
  • Influenza A (H3N2) virus
  • Influenza B virus

The trivial viral shots are usually manufactured by using virus grown in eggs. The recommendations for different types of viral shots differ with age and vaccines for infants are not the same as for adults.

Mostly flu vaccines are administered using a needle. However, some of the dose specific trivial shots are given with the help of a jet injector, ranging in people aged 18 to 64 years. For the people who are 18 and older are the trivalent shot containing virus grown in cell culture.

CDC claims that the flu vaccinations are safe for pregnant women and their fetus and has the potential to avoid serious health complications of flu like pneumonia. These shots are safe to be administered in any trimester of pregnancy. There are no adverse side effects associated with the vaccines except mild soreness or redness on the area of injection.

A population based surveillance study published in Jun 2011 in the American Journal of Obstetrics & Gynecology validated the work of the study under consideration by analyzing the impact of maternal immunization on influenza related hospitalization cases in infants and found 48% reduction in the laboratory-confirmed influenza hospitalizations in the infants whose mothers used influenza vaccine during pregnancy.

Another study published in the American Journal of Perinatology (2004) also discussed the effectiveness of influenza vaccine in pregnant women and pointed out towards less hospitalizations and outpatient visits for respiratory illness in both the pregnant women and their infants.

A study published on the similar grounds in International Journal of Women’s Health also urged pregnant women getting influenza shots during pregnancy (July, 2014).