Simple, clear infection control messages needed as influenza season picks up

Influenza is expected to affect up to 50% or more of the population this season and the number of those experiencing illness attributable to novel H1N1 is expected to exceed the number of clinicians available to provide care, according to influenza experts at the AAP 2009 National Conference.

Forty-one states had reported widespread influenza activity as of October 10, CDC surveillance data indicate, and the occurrence of influenza-like illness currently exceeds what is typically seen this time of year, and has far surpassed activity observed during the past three seasons.

“The majority of previously healthy children aged 2 years and older will not require antiviral therapy,” Joseph A. Bocchini, Jr., MD, professor in the department of pediatrics at the State University Health Services Center in Shreveport, Louisiana, said during an H1N1 session.

Despite the increased ease of transmission, H1N1 has similar morbidity to seasonal influenza, making it important for pediatricians to encourage families to develop a home plan for managing the disease, Steven E. Krug, MD, professor of pediatrics at Northwestern University Feinberg School of Medicine and chair of the AAP Disaster Preparedness Advisory Council said during a press conference at the meeting.

Practicing good home isolation, proper hand hygiene and cough etiquette and maintaining strong communication with the medical home should be sufficient for managing most influenza like illness, according to Krug.

However, both he and Bocchini emphasized that pediatricians must not wait for laboratory results to initiate prompt antiviral therapy with oseltamivir or zanamivir for patients who have influenza-like illness and the following risk factors:

Children aged younger than 2 years.
Pregnant women.
Any person with a chronic medical or immunosuppressive condition.
Elderly individuals aged 65 and older.

“This is primarily a pediatric pandemic,” Bocchini said. “Eleven U.S. pediatric deaths have occurred from influenza infection during the past week, 10 of which were attributable to H1N1.”

Members of the AAP and the CDC have collaborated to create an easy-to-use triage algorithm to help guide physicians when providing care to children with influenza-like illness. The document, which provides diagnostic checklists by age and appropriate actions based on a child’s symptoms, is available online.

Bocchini reminded health care providers that vaccination remains the primary recommended influenza infection control strategy, a message that much of the public seems to be receiving as evidenced by a 300% increase in the proportion of Americans seeking vaccination so far this year.

“Our goal is to vaccinate as many children as possible as soon as seasonal and H1N1 vaccines become available.”

As of today, about 82 million of 114 million manufactured doses of seasonal influenza vaccine and about 6 million of the 11 million manufactured doses of H1N1 vaccine have been shipped and made available for distribution.

However, the current H1N1 vaccine supply is not enough to vaccinate all recommended groups. Health authorities encourage clinicians prioritize vaccination efforts by targeting pregnant women, individuals who live with or care for infants aged younger than 6 months, health care workers and emergency medical personnel, individuals aged 6 months to 24 years and elderly people aged older than 65.

“There has been no significant antigenic drift as yet found in the current H1N1 virus, so the vaccine is very well matched, and is expected to be highly effective,” Bocchini said.

Four different vaccines have been licensed including infant and pediatric inactivated and live-attenuated formulations.

Preliminary dosing recommendations for children aged 6 months to 9 years of age require two doses separated by an approximate four-week interval. Children 10 years and older require one dose.

Back-to-back vaccination with both inactivated seasonal and H1N1 vaccines is acceptable, but administration of both live-attenuated vaccines at the same time is not recommended.

Data from additional studies are expected toward the end of October and into November that may change the necessary time between doses, according to Bocchini. Additionally, the Advisory Committee on Immunization Practices is likely to discuss the possibility of harmonizing seasonal and H1N1 vaccines today and tomorrow. – by Nicole Blazek

#P4047. American Academy of Pediatrics National Conference and Exhibition; Washington, D.C.: Oct. 17-20, 2009.