A new study from the University of Maryland School of Medicine’s Center for Vaccine Development (CVD) and the Center for Vaccine Development of Mali (CVD-Mali) reveals that immunizing mothers against influenza can decrease the risk of their infant getting the flu by 70% during the first four months of life.

The study, published in Lancet Infectious Disease, is the largest study to date to show that maternal vaccination against influenza is feasible and effective, even in one of the world’s least developed countries, according to a University of Maryland (UM) School of Medicine news release.

The research took place in Bamako, Mali, in West Africa, and performing the trial there was important. Samba O. Sow, MD, MS, co-lead author of the study and director-general of CVD-Mali, says, “Mali is one of the poorest countries in the world. But it has been a pioneer in introducing five new vaccines for meningitis, pneumonia and severe gastroenteritis in both young children and adults.” The research team studied 4,193 pregnant women, and about half of the women received a flu vaccine, while the other half received a vaccine for meningitis. The scientists followed the women’s infants for 6 months after birth.

The results of the study showed that in the group whose mothers had been vaccinated against the flu, vaccine efficacy was close to 70% in the first 4 months after birth. This number fell to 57% by 5 months and disappeared by 6 months. Vaccine efficacy refers to the percentage of reduction in disease incidence in a vaccinated group compared to an unvaccinated group.

“These results are an important early step toward implementing maternal immunization against influenza to protect young infants, and the results are impressively positive,” says senior author of the study Myron M. Levine, MD, DTPH. “However, much more needs to be done. A much larger study is necessary to measure the impact on more severe forms of influenza that lead to hospitalization and death.”

Milagritos D. Tapia, MD, lead author of the trial, explains, “Most pregnant women in Mali already receive a tetanus vaccine during pregnancy, to prevent tetanus in the newborn and the mother at the time of delivery. So a system to deliver vaccine to pregnant women already exists, and we can add the flu vaccine to this process”

The study was funded by a grant from the Bill & Melinda Gates Foundation. According to Keith Klugman, MD, PhD, director for Pneumonia at the foundation, “The new data highlight maternal immunization as a safe and effective way to protect very young infants against flu in some of the poorest places in the world. We can protect babies by vaccinating their mothers and we’re excited to see what the future holds for expanded possibilities in maternal immunization.”

Source: University of Maryland School of Medicine