Flu Vaccine Protects Pregnant Woman's Baby And Does Not Cause Miscarriage

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Main Category: Flu / Cold / SARS
Also Included In: Pregnancy / Obstetrics;  Immune System / Vaccines
Article Date: 24 Oct 2011 - 0:00 PDT

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Apart from protecting a newborn infant from flu for four months, the flu vaccine does not raise the risk of miscarriage, Kathleen Neuzil, MD, member of the Infectious Disease Society of America's Pandemic Influenza Task Force explained at their 49th Annual Meeting. Various presentations at the meeting are showing that pregnant mothers are getting the message not only about the flu shot's importance, but also its safety.

A newborn whose mother was not vaccinated is particularly vulnerable to flu because he/she is more likely not to be born with protective immunity and cannot be vaccinated for at least six months. A newborn who becomes infected with influenza is at a higher risk of complications, and even death, compared to older humans.

Dr. Neuzil, MD, who is also clinical professor in the School of Medicine at the University of Washington, Seattle, said:

"Pregnant women are understandably concerned about protecting their unborn babies, which makes it all the more important for them to understand that getting a flu shot during pregnancy is an important way to protect the baby, as well as themselves. These new data on the safety and effectiveness of these vaccines is reassuring, and the increasing number of pregnant women receiving the vaccine affirms that women are hearing the message about the vaccine's benefits."

Influenza Vaccination Protects Newborns

A pregnant mother who is vaccinated protects herself from flu, which has benefits for the baby during pregnancy. The mother also passes on the antibodies caused by the vaccine onto the baby, who is protected during his/her first four months after being born, according to studies carried out at the University of Utah.

27 women were involved in the Utah study. 41% (11) of them had been given the seasonal flu shot while 59% (16) had not. Blood tests immediately after birth showed that all the babies born to the mothers who had been vaccinated had antibodies against flu, compared to just 31% of those born to unvaccinated mothers. At two months 60% of babies born to vaccinated mothers had antibodies compared to none of the other babies. At four months 11% of the babies born to vaccinated mothers had antibodies.

Lead author, Julie H. Shakib, DO, MPH, assistant professor of pediatrics at the University of Utah, Salt Lake City, said:

"Our research suggests that maternal vaccination does provide some protection from the flu for a few months after birth. Pregnant women should receive the vaccine as soon as it becomes available to protect themselves as well as their babies."

No increase in miscarriage risk from flu shots

A large study found no association between receiving the flu shot during pregnancy and the risk of miscarriage. Researchers from Wisconsin's Marshfield Clinic compared 243 pregnant women who had a miscarriage with 243 who didn't. They had all received care from managed care organizations in the Vaccine Safety Datalink.

After gathering and analyzing their data, the researchers found no increased likelihood of having received a flu shot during the four weeks before the miscarriage, compared to those who had no miscarriage. 38 women who had a miscarriage had received the flu shots compared to 31 who had not miscarried - this is not a statistically significant difference, the scientists stressed.

Stephanie A. Irving, MS, epidemiologist at Marshfield Clinic Research Foundation, said:

"Safety concerns are one of the top reasons pregnant women provide for abstaining from getting the influenza vaccine. Our findings should help pregnant women feel more comfortable about getting vaccinated."

The message of benefits getting through

A study carried out at Christiana Care Health System in Newark, Del. Found that pregnant mothers appear to be getting the message about the benefits and safety of the flu vaccine. In a study involving 300 pregnant women, before 2009 less than 15% got vaccinated, compared to 55% after 2010.

Marci L. Drees, MD, hospital epidemiologist at Christiana Health Care, said:

"Although there's still room for progress - nearly half of pregnant women still aren't getting the vaccine - we're encouraged that vaccination levels didn't drop to anywhere near what they were before the H1N1 pandemic. Because many pregnant women only see their obstetricians during their pregnancy, it's important that OBs encourage pregnant women to get the vaccine and have it available, which makes a big difference."

Dr. Neuzil said:

"Pregnant women are one of the groups identified as a priority for receiving the influenza vaccine, but historically have been the least likely among those groups to get the vaccine. It's good to learn the message of the importance of vaccination is getting through to pregnant women, and this research should provide even more comfort."

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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