Prenatal Influenza Vaccine May Prevent Flu in Infants

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Prenatal use of influenza vaccine may help young infants be protected against influenza or flu, according to a new study in the Feb 2011 issue of Archives of Pediatrics and Adolescent Medicine.

The study showed that infants whose mothers received influenza vaccine were 41 percent less likely to acquire laboratory-confirmed influenza virus infection and 39 percent less likely to be hospitalized for influenza-like illness.

For the study, Angelia A. Eick Ph.D. then of Johns Hopkins Bloomberg School of Public Health in Baltimore and colleagues followed 1,269 women who delivered babies during one of three flu seasons and received information on maternal influenza vaccine and flu status in infants from 1,160 of them.

These findings mean that maternal vaccination may provide extra protection for young infants. Infants younger than 6 months are not eligible for influenza vaccine; they, particularly those who are not breastfed and live in a risky environment, are at higher risk of getting flu.

The study was sponsored by government health agencies and drug companies including the National Vaccine Program Office, Department of Health and Human Services, the Office of Minority Women's Health, Centers for Disease Control and Prevention, Aventis-Pasteur and Evans-Powderject, according to a statement by the journal.

A health observer suggests that the study reveals a possibility that prenatal use of influenza vaccine may help young infants ward off flu infection.  Indeed, the study found babies born to mothers who were vaccinated had higher levels of antibodies than those whose mothers were not vaccinated.

Still, the observer said many other variables may exist and could be involved in the association between flu shots and incidence of flu and hospitalization, which may not be a causal relationship.  One possibility is that those mothers who received the flu vaccine might be more health conscious and they might follow a better lifestyle which may, overall, provide some extra protection for their babies.

For instance, women taking vitamin D supplements or get sufficient sun exposure during pregnancy and after birth may more likely have babies who are less vulnerable to flu.  Additionally, infants who are breastfed are less likely to acquire the flu. It is unclear whether the current study considered these factors.

In any case, a few precautions women can take before and after birth to lower the risk of flu in their babies include:

* breastfeeding their babies for at least the first six months;
* obtaining sufficient sun exposure if possible;
* in the winter, or when the sun is in short supply, taking vitamin D supplements may reduce  risk.   

Women can take these precautions regardless of their vaccination status because the influenza vaccine itself has a low efficacy and extra measures can help boost protection.

How effective is vitamin D against flu?

A small Japanese trial has proved that taking vitamin D year around can be at least as effective as providing the influenza vaccine to school children.

In 2009, Dr. John Cannell reported in his newsletter that one physician in Wisconsin and another in Georgia told him that they observed that taking high doses of vitamin D is highly effective against H1N1.

Vitamin D has proven to be protective against flu.  A study published not long ago in the prestigious journal Science explained in detail how vitamin D helps fight infections.  For one thing, per Dr. Cannell’s report, vitamin D helps produce antibacterial peptides in the human body, which is why taking the vitamin helps fight flu or influenza.

Another benefit of taking vitamin D is that fetuses need vitamin D to better develop their brains.  Some mental disorders are associated with prenatal vitamin D deficiency, according to Dr. Cannell.

Editing by Rachel Stockton

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