Maternal Influenza Vaccination and Effect on Influenza Virus Infection in Young Infants

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Maternal Influenza Vaccination and Effect on Influenza Virus Infection in Young Infants

Angelia A. Eick, PhD; Timothy M. Uyeki, MD, MPH, MPP; Alexander Klimov, PhD; Henrietta Hall, MS; Raymond Reid, MD; Mathuram Santosham, MD; Katherine L. O?Brien, MD, MPH

Arch Pediatr Adolesc Med. Published online October 4, 2010. doi:10.1001/archpediatrics.2010.192

Objective To assess the effect of seasonal influenza vaccination during pregnancy on laboratory-confirmed influenza in infants to 6 months of age.

Design Nonrandomized, prospective, observational cohort study.

Setting Navajo and White Mountain Apache Indian reservations, including 6 hospitals on the Navajo reservation and 1 on the White Mountain Apache reservation.

Participants A total of 1169 mother-infant pairs with mothers who delivered an infant during 1 of 3 influenza seasons.

Main Exposure Maternal seasonal influenza vaccination.

Main Outcome Measures In infants, laboratory-confirmed influenza, influenzalike illness (ILI), ILI hospitalization, and influenza hemagglutinin inhibition antibody titers.

Results A total of 160 mother-infant pairs had serum collected and were included in the analysis. Among infants, 193 (17%) had an ILI hospitalization, 412 (36%) had only an ILI outpatient visit, and 555 (48%) had no ILI episodes. The ILI incidence rate was 7.2 and 6.7 per 1000 person-days for infants born to unvaccinated and vaccinated women, respectively. There was a 41% reduction in the risk of laboratory-confirmed influenza virus infection (relative risk, 0.59; 95% confidence interval, 0.37-0.93) and a 39% reduction in the risk of ILI hospitalization (relative risk, 0.61; 95% confidence interval, 0.45-0.84) for infants born to influenza-vaccinated women compared with infants born to unvaccinated mothers. Infants born to influenza-vaccinated women had significantly higher hemagglutinin inhibition antibody titers at birth and at 2 to 3 months of age than infants of unvaccinated mothers for all 8 influenza virus strains investigated.

Conclusions Maternal influenza vaccination was significantly associated with reduced risk of influenza virus infection and hospitalization for an ILI up to 6 months of age and increased influenza antibody titers in infants through 2 to 3 months of age.


Author Affiliations: Center for American Indian Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland (Drs Eick, Reid, Santosham, and O?Brien); Influenza Division, National Center for Immunization and Respiratory Viruses, Centers for Disease Control and Prevention, Atlanta, Georgia (Drs Uyeki and Klimov and Ms Hall). Dr Eick is now with the Armed Forces Health Surveillance Center, Silver Spring, Maryland.

http://archpedi.ama-assn.org/cgi/content/short/archpediatrics.2010.192

 

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Re: Maternal Influenza Vaccination and Effect on Influenza Virus Infection in Young Infants

Flu jab for pregnant women cuts virus in babies

Antibodies developed by the mother in response to the innoculation are passed to the child via the placenta and breastfeeding.

The US study of 160 women and their infants found that the babies of those vaccinated while pregnant, were 41 per cent less likely to get flu up to six months old.


The chance of such a baby being hospitalised with a flu-like illness was also 39 per cent lower than those whose mothers had not been vaccinated while pregnant, found Dr Angelia Eick, who was working at the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland.

Writing in the Archives of Paediatrics and Adolescent Medicine, she and her colleagues concluded: "These findings provide support for the added benefit of protecting infants from influenza virus infection up to six months, the period when infants are not eligible for influenza vaccination but are at highest risk of severe influenza illness."

Last week the Department of Health announced that all pregnant women would be offered the seasonal flu vaccine for the first time this winter.

The move was prompted by data from last year's H1N1 swine flu pandemic, which showed expectant mothers were four times more likely to be treated in hospital for it than the general population. The mortality rate among them also appeared to be twice the norm. The H1N1 strain is to be included in the vaccine.

A decision over whether to continue giving pregnant women the seasonal flu jab after the coming winter has yet to be taken.

http://www.telegraph.co.uk/health/h...-for-pregnant-women-cuts-virus-in-babies.html