According to results of a randomized controlled trial published in the Canadian Medical Association Journal (CMAJ), the effects of influenza immunization on babies born to vaccinated mothers shows a considerable positive effect on birth weight.
The study, part of the Mother’sGift project examining the safety and effectiveness of pneumococcal and influenza vaccines in pregnant women in Bangladesh, enrolled 340 healthy pregnant women in Bangladesh, in their third trimester. The researchers randomly assigned 170 participants to receive influenza vaccine, and the remaining 170 to receive pneumococcal vaccine as control.
The team compared the weight of babies born during a circulation of an influenza virus, and again when there was limited circulation.
Babies that are small for gestational age are at heightened risk of health problems and other issues during their life.
When the virus was circulating, the team discovered that there were less babies who were small for gestational age in the influenza vaccine group (25.9%), than in the control group (44.8%). When the virus was circulating, the team found that the mean birth weight was 3,178 g in the influenza vaccine group, and 7% higher than birth weight in control group (2,978 g).
The rate of premature births was also lower in the influenza vaccine group. For both groups, the proportion of small-for-gestational-age births was similar when the virus was not circulating.
Dr. Mark Steinhoff, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, and his co-authors, explained:
“We found that immunization against influenza during pregnancy had a substantial effect on mean birth weight and the proportion of infants who were small for gestational age.
Our data suggest that the prevention of infection with seasonal influenza in pregnant women by vaccination can influence fetal growth.”
According to the teams calculation, 10 maternal influenza vaccinations given throughout the year prevented 1 small-for-gestational-age birth, decreasing to 6 vaccinations during the time the influenza virus was circulating.
According to the researchers, if their findings are supported by additional studies, influenza vaccine could help children have a better start in life if the mother receives influenza vaccine, in addition to routine vaccination programs during pregnancy.
The study was carried out by a team of US and Bangladeshi investigators from the Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio; Johns Hopkins University, Baltimore, Maryland; Emory University, Atlanta, Georgia; the International Centre for Diarrheal Disease Research, Dhaka, Bangladesh; and the Centers for Disease Control and Prevention, Atlanta, Georgia.
Written by Grace Rattue