OK, so this is one of those times when a research article comes out and you have to say, “Don’t go jumping to any crazy conclusions!” 8 weeks is still better than nothing! And those are critical 8 weeks.
What am I talking about?
JAMA Pediatrics recently published research from a new study that indicates infants may only be protected by maternal flu vaccination from the flu virus for 8 weeks after birth. The team studied over 2,000 babies – about half of the mothers received the actual flu vaccination while pregnant and the other half received a placebo. After the babies were born, blood samples were taken at 7 days of life and again at 8 weeks, 16 weeks, and 24 weeks after birth. The researchers looked for hemagglutination inhibition (HAI) antibodies in the bloodstream. HAI antibodies are an indicator of protection against flu; higher levels indicate higher protection. The babies were also monitored closely for any flu-like symptoms.
What the information tells us:
The researchers found that in the first 8 weeks of life, maternal flu vaccination was 85.6 percent effective in protecting the baby. But after that age, the efficacy dropped significantly. HAI levels also dropped significantly to only 10% by 24 weeks after birth.
The research team stated: “We and others have previously demonstrated that the administration of IIV3 during pregnancy confers protection against symptomatic influenza infection to the infants of the vaccinated mothers; here we show that the duration of this protection is likely to be limited to the first 8 weeks of age.”
The Center for Disease Control (CDC) rates infants under the age of six months as one of the highest risk groups for needing to be hospitalized due to the flu. Yet babies this age are not eligible to receive the flu vaccination. Now that these studies indicate babies are only adequately protected for two months after birth, the researchers indicated that alternative strategies are needed to protect infants from 8 weeks until six months of age.
BUT… let’s not forget
Previous studies have shown that 97% of infants who become infected with the flu vaccine were not protected by maternal flu vaccination. Because of this it is still strongly urged for pregnant mothers to receive the flu vaccination, even if the protection is not for as long as previously believed.
So… if you hear that maternal flu shots aren’t doing anything to protect the baby (cause let’s be real, we know how those rumor mills go) it’s NOT the truth. Continue to get your flu shot pregnant mamas. It’s important.
In the meantime, let’s hope the researchers get on something to protect them from ages 2 – 6 months.
Duration of infant protection against influenza Illness conferred by maternal immunization: Secondary analysis of a randomized clinical trial, Marta C. Nunes et al., JAMA Pediatrics, doi:10.1001/jamapediatrics.2016.0921, published online 5 July 2016, abstract.