Mild Prematurity Aggravates Risk Of Medically Attended Respiratory Syncytial Virus Infection

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Main Category: Pediatrics / Children's Health
Also Included In: Respiratory / Asthma
Article Date: 06 May 2009 - 1:00 PST

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BALTIMORE - New data reveal that babies who are only mildly premature are at increased risk of respiratory syncytial virus (RSV) infection needing medical treatment, researchers announced here at the Pediatric Academic Societies (PAS) Annual Meeting 2009.

Gabriel Escobar, MD, with Kaiser Permanente Medical Center in Oakland, California, and colleagues elsewhere quantified the relationship between neonatal characteristics and the occurrence of medically attended RSV infection in the first year of life among babies ≥33 weeks gestation.

"While RSV infection is recognized to be more severe among premature infants, recent laboratory-confirmed data disaggregated by gestational age have not been available," Dr. Escobar pointed out. "Less attention has been given to late pre-term infants (a gestational age of 33 to 36 weeks), many of whom require intensive care in the neonatal period."

The study population included 108,794 babies born at 33 weeks' gestation or later who were discharged from six hospitals between January 1, 1996 and December 11, 2002.

The neonatal characteristics assessed included gestational age, race, birth weight, sex, oxygen exposure in the neonatal period, neonatal discharge month, siblings, and being small for gestational age.

Results showed that the rate of use of supplemental oxygen during the neonatal period was 6.32% among babies 33 to 36 weeks and 1.63% among babies ≥37 weeks, and the rate of use of assisted ventilation was 9.92% and 0.86% in the two groups, respectively.

Overall, the risk of RSV infection was greater in infants with the following characteristics: siblings, lower gestational age, males, and oxygen exposure in the neonatal period.

Dr. Escobar emphasized that the study used a conservative definition of medically attended RSV infections, which may represent a potential limitation. In addition, the study cohort was an insured population in a program with an unusually high degree of integration and provision of services, which may be associated with lower attack rates.

"Overall, the results demonstrate that medically attended RSV infection is more common in premature infants, even if they are not very premature," he said.

Finally, the California investigator called for additional research to identify strategies to prevent RSV infection or decrease related sequelae like RSV bronchiolitis in late pre-term infants.

Respiratory syncytial virus infection in infancy and childhood is common, with attack rates approaching 100% by the end of year three.

The study was sponsored by MedImmune, LLC in Gaithersburg, Maryland.

By Jill Stein
Jill Stein is a medical writer based in Paris, France.
jillstein03(at)mail.com
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