Friday, April 1, 2016

Incidence of still births halved after Seasonal Trivalent Influenza Vaccination During Pregnancy: First Population-Based Retrospective Cohort Study.



The Obstetric Practice and Immunization Expert Work Group of the American College of Obstetricians and Gynecologists (ACOG) updated the committee opinion that all pregnant women should receive influenza vaccination back in 2014. World Health Organizations and CDC guidelines recommend seasonal influenza vaccinations(inactivated influenza vaccine ) for pregnant women in any trimester. However, the live attenuated vaccine is not recommended for pregnant women but can be used safely during the postnatal period.

Pregnancy puts women at increased risk pneumonia and acute respiratory illnesses because of lowered immunity. Antenatal Infections are also linked to fetal mortality and preterm labor. But, in spite of it only 50% of women get themselves immunized due to safety concerns for the fetus.

Recent research shows that there are other maternal and fetal benefits of seasonal influenza vaccination, other than just preventing the flu. A Canadian study by published in Canadian Medical Association Journal has shown that Influenza Vaccination in pregnancy reduces the odds of having a preterm delivery or delivery of a low-birth-weight baby compared with pregnant women who did not get the vaccine.

A recent Population based retrospective study by published online on March 30, 2016 in the journal of Clinical Infectious Diseases  have shown that women in western Australia who received the vaccine have half the risk of stillbirths as compared to women who do not receive the shot.

The lead author Annette K. Regan, MPH, from the School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, and Western Australia Department of Health, Shenton Park said in a news release “During the 2009 H1N1 pandemic, we saw a similar reduction in stillbirths following vaccination,” she added that “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 researchers in Australia analyzed midwives’ data retrospectively. A total of 58,008 women delivered during the winter flu season in the year 2012 and 2013 in Western Australia. Out of which 5076 women received the influenza vaccine, and 377 stillbirths occurred. After adjusting for confounders (maternal smoking, indigenous status, and propensity for vaccination) the risk of stillbirth among vaccinated mothers was 51 percent lower than the risk among women who had not been vaccinated.

The observed rate of stillbirths also increased around the time of Influenza virus circulation, suggesting a link between the virus and stillbirths.

The authors call for further research to look into causes of decrease in still birth rates following Influenza vaccination.

"Given the growing body of evidence supporting the health benefits to mother and infant, concerted efforts are needed to improve seasonal influenza vaccine coverage among pregnant women," the researchers conclude.

The study limitations were being retrospective, depending upon data reporting by healthcare workers and generalizability of findings to women in developing countries.

The study also has wider implications on global public health level as vaccination against Influenza is an attainable step to avert stillbirths. In 2015, an estimated 2·6 million (uncertainty range 2·4–3·0 million) babies were stillborn, with 70% of infant death around the time of birth.



References:
http://cid.oxfordjournals.org/content/early/2016/03/10/cid.ciw082.abstract

No comments:

Post a Comment