Nav: Home

Seasonal influenza vaccination during pregnancy may reduce risk of stillbirth

March 31, 2016

Seasonal influenza vaccination may guard against stillbirth, a new study published in Clinical Infectious Diseases and available online suggests. Researchers in Western Australia analyzed data from nearly 60,000 births that occurred during the southern hemisphere's 2012 and 2013 seasonal influenza epidemics, and found that women who received the trivalent influenza vaccine during pregnancy were 51 percent less likely to experience a stillbirth than unvaccinated mothers.

The retrospective study used midwives' records to examine a cohort of 58,008 births: 52,932 to mothers who had not received the vaccine and 5,076 to mothers who had been vaccinated during pregnancy. All births took place in Western Australia between April of 2012 and December of 2013. The adjusted risk of stillbirth among vaccinated mothers was 51 percent lower than the risk among women who had not been vaccinated.

Researchers also observed that stillbirth rates increased after periods of influenza virus circulation and decreased during the months prior to the influenza season, although the seasonal differences were not statistically significant. The study's results are consistent with those of a 2000 study in Switzerland that recorded increased incidence of stillbirth in relation to the northern hemisphere's influenza season, as well as with similar research conducted during the influenza A/H1N1 pandemic.

"During the 2009 H1N1 pandemic, we saw a similar reduction in stillbirths following vaccination," said study author Annette Regan, MPH, of the Western Australia Department of Health. "Our results are particularly exciting since they show we can get the same protection during seasonal epidemics, which occur every winter. Unfortunately, we know that about 40 percent of pregnant women go unvaccinated, missing out on these benefits."

The U.S. Centers for Disease Control and Prevention recommends annual flu vaccination for everyone 6 months of age and older, including pregnant women during any trimester of their pregnancy. Pregnancy puts women at an increased risk of developing serious complications related to influenza, including acute respiratory distress syndrome and pneumonia. Infection during pregnancy has also been linked to fetal mortality and premature births. But concern for the safety of the fetus dissuades many expectant mothers from vaccination.

The new study's findings not only support the safety of influenza vaccination during pregnancy, but also suggest that vaccination protects against stillbirth. The authors noted that the protective benefits they observed "may be an underestimate of the true effect measure" due to the methods of data analysis employed in their study.

Over 3 million stillbirths occur worldwide each year, and in developed countries, stillbirth accounts for 70 percent of infant deaths around the time of birth. Establishing a connection between influenza season and stillbirth could have global implications for infant mortality.

Further research is needed to confirm the possible links between stillbirth, influenza season, and vaccination, the study's findings indicate. But the researchers are hopeful that their data will be useful for communicating vaccination's potential health benefits to expectant mothers and health care providers.

"I'm hoping results like these can convince more pregnant women to get vaccinated each year," Regan said.

Fast Facts
  • In this retrospective cohort study, women in Western Australia who received the seasonal trivalent influenza vaccine during pregnancy showed a 51 percent lower risk of experiencing a stillbirth than unvaccinated expectant mothers.

  • Observed rates of stillbirth increased just after periods of influenza virus circulation, suggesting a link between incidence of stillbirth and the influenza season.

  • Over 3 million stillbirths occur worldwide each year, and in developed countries, stillbirth accounts for 70 percent of infant deaths around the time of birth.

-end-
Editor's note: The study was funded by the Western Australia Department of Health. The study authors' affiliations, acknowledgments, and disclosures of financial support and potential conflicts of interests, if any, are available in the article. For an embargoed copy of the study, please contact Emily Zaideman (312-558-1770, ezaideman@pcipr.com).

Clinical Infectious Diseases is a leading journal in the field of infectious disease with a broad international readership. The journal publishes articles on a variety of subjects of interest to practitioners and researchers. Topics range from clinical descriptions of infections, public health, microbiology, and immunology to the prevention of infection, the evaluation of current and novel treatments, and the promotion of optimal practices for diagnosis and treatment. The journal publishes original research, editorial commentaries, review articles, and practice guidelines and is among the most highly cited journals in the field of infectious diseases. Clinical Infectious Diseases is an official publication of the Infectious Diseases Society of America (IDSA). Based in Arlington, Va., IDSA is a professional society representing nearly 10,000 physicians and scientists who specialize in infectious diseases. For more information, visit http://www.idsociety.org. Follow IDSA on Facebook and Twitter.

Infectious Diseases Society of America

Related Influenza Articles:

How proteins help influenza A bind and slice its way to cells
Researchers have provided new insight on how two proteins help influenza A virus particles fight their way to human cells.
Eating elderberries can help minimize influenza symptoms
Conducted by Professor Fariba Deghani, Dr. Golnoosh Torabian and Dr.
Mechanism to form influenza A virus discovered
A new study by Maria João Amorim's team, from the Gulbenkian Institute of Science, now reveals where the genomes of the influenza A virus are assembled inside infected cells.
Bat influenza viruses could infect humans
Bats don't only carry the deadly Ebola virus, but are also a reservoir for a new type of influenza virus.
New VaxArray publication on influenza neuraminidase quantification
InDevR Inc. announced publication of 'A Neuraminidase Potency Assay for Quantitative Assessment of Neuraminidase in Influenza Vaccines' in npj Vaccines.
Fighting mutant influenza
Another flu season is here, which means another chance for viruses to mutate.
Influenza vaccine delays are a problem for pediatricians
Uptake of influenza vaccine among children is low compared to other childhood vaccines, and missed opportunities for vaccination play an important role in this low uptake.
For a better influenza vaccine, focus on the neglected 'N'
In the April 5, 2018, issue of the journal Cell, researchers push for greater emphasis on the neglected viral-surface influenza protein neuraminidase.
Previous influenza virus exposures enhance susceptibility in another influenza pandemic
New data analysis suggests that people born at the time of the 1957 H2N2 or Asian Flu pandemic were at a higher risk of dying during the 2009 H1N1 Swine Flu pandemic as well as the resurgent H1N1 outbreak in 2013-2014.
Annual influenza vaccination does not prevent natural immunity
Earlier studies have suggested that having repeated annual influenza vaccination can prevent natural immunity to the virus, and potentially increase the susceptibility to influenza illness in the event of a pandemic, or when the vaccine does not 'match' the virus circulating in the community.
More Influenza News and Influenza Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.