Flu shot during pregnancy shows unexpected benefits in large study

May 22, 2012

Getting a flu shot during pregnancy provides unanticipated benefits to the baby, according to the authors of a large population-based study examining the issue. Specifically, the study showed that H1N1 vaccination during the pandemic was associated with a significantly reduced risk of stillbirth, preterm birth and extremely small babies at birth.

Researchers at the Ottawa Hospital Research Institute (OHRI), the CHEO Research Institute and the University of Ottawa (uOttawa) used data from Ontario's birth record database, BORN, to examine 55,570 single-child births that took place in Ontario during the H1N1 pandemic. The resulting paper, "H1N1 during Pregnancy and Fetal and ," was recently published by the .

The study shows that, compared to pregnant women who were not immunized against H1N1, mothers who received the H1N1 vaccination were:

  • 34% less likely to have a stillbirth,
  • 28% less likely to deliver before 32 weeks, and
  • 19% less likely to give birth to a child with a birth weight for in the bottom third percentile.
"These are all significant results, but especially interesting is the finding that the vaccinated mothers were one-third less likely to have a stillborn child," says lead author Deshayne Fell, an epidemiologist for BORN Ontario. "This is one of the only studies large enough to evaluate the association between maternal and stillbirth—a very rare event."

"What surprised me and the research team was the strength of the protective benefits we found," says co-author Dr. Ann Sprague, the Scientific Manager of BORN Ontario at the Children's Hospital of Eastern Ontario (CHEO) Research Institute.

The study also found no increase in adverse outcomes for H1N1-vaccinated mothers and their babies during the weeks before and just after birth, also referred to as the perinatal period.

"The findings of this study are very helpful," says co-author Dr. Mark Walker, a Senior Scientist at OHRI, a High-Risk Obstetrician at The Ottawa Hospital, and a Professor and Tier One Research Chair in Perinatal Research at the University of Ottawa.

"Pregnant women are generally very, very careful about what they put into their bodies. For health-care providers like me, such a large-scale study that shows no adverse perinatal outcomes resulting from the H1N1 flu vaccine will be extremely helpful when discussing maternal vaccination."

Of all the single-child births recorded from November 2009 to April 2010, 42% of the women received the H1N1 vaccination, which makes the findings robust. BORN—the Better Outcomes Registry & Network—collects data from all births in Ontario. In order to conduct the research for this study, questions about H1N1 vaccination were added to the database in advance of the H1N1 vaccine becoming available. BORN includes demographic data that allowed the research team to correct for smoking, education and income; however, as with any population-based study, it may not be possible to account for all influencing factors.

Explore further: Research demonstrates link between H1N1 and low birth weight

More information: ajph.aphapublications.org/doi/ … 105/AJPH.2011.300606

Related Stories

Research demonstrates link between H1N1 and low birth weight

May 2, 2011
In 2009, the United States was gripped by concern for a new winter threat: the H1N1 strain of influenza. According to research conducted through that winter, pregnant women were right to be concerned.

Influenza vaccination of pregnant women helps their babies

February 21, 2012
Vaccinating pregnant women against the influenza virus appears to have a significant positive effect on birth weight in babies, according to a study published in CMAJ (Canadian Medical Association Journal).

The H1N1 flu vaccine protects both pregnant women and newly-borns

December 7, 2011
The researchers studied the immune response of 107 pregnant women after they were injected with a single dose of non-adjuvant H1N1 vaccine. They concluded that the influenza shot boosted the immune response in pregnant women ...

Excessive weight gain during pregnancy a predictor for above-average birth weight

April 17, 2012
One out of every two women of reproductive age is overweight or obese. Researchers from the Children's Hospital of Eastern Ontario (CHEO) Research Institute, from the University of Ottawa (faculties of Medicine and Health ...

Influenza vaccination during pregnancy protects newborns

June 23, 2011
Infants born to mothers who received the influenza (flu) vaccine while pregnant are nearly 50 percent less likely to be hospitalized for the flu than infants born to mothers who did not receive the vaccine while pregnant, ...

Pediatric flu vaccination: Understanding low acceptance rates could help increase coverage

April 28, 2011
A study of H1N1 and seasonal influenza vaccination in a sample of black and Hispanic children in Atlanta found a low rate of vaccine acceptance among parents and caregivers. Only 36 percent of parents and caregivers indicated ...

Recommended for you

Finish your antibiotics course? Maybe not, experts say

July 27, 2017
British disease experts on Thursday suggested doing away with the "incorrect" advice to always finish a course of antibiotics, saying the approach was fuelling the spread of drug resistance.

Co-infection with two common gut pathogens worsens malnutrition in mice

July 27, 2017
Two gut pathogens commonly found in malnourished children combine to worsen malnutrition and impair growth in laboratory mice, according to new research published in PLOS Pathogens.

Phase 3 trial confirms superiority of tocilizumab to steroids for giant cell arteritis

July 26, 2017
A phase 3 clinical trial has confirmed that regular treatment with tocilizumab, an inhibitor of interleukin-6, successfully reduced both symptoms of and the need for high-dose steroid treatment for giant cell arteritis, the ...

A large-scale 'germ trap' solution for hospitals

July 26, 2017
When an infectious airborne illness strikes, some hospitals use negative pressure rooms to isolate and treat patients. These rooms use ventilation controls to keep germ-filled air contained rather than letting it circulate ...

Researchers report new system to study chronic hepatitis B

July 25, 2017
Scientists from Princeton University's Department of Molecular Biology have successfully tested a cell-culture system that will allow researchers to perform laboratory-based studies of long-term hepatitis B virus (HBV) infections. ...

Male hepatitis B patients suffer worse liver ailments, regardless of lifestyle

July 25, 2017
Why men with hepatitis B remain more than twice as likely to develop severe liver disease than women remains a mystery, even after a study led by a recent Drexel University graduate took lifestyle choices and environments ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.