Flu spray is better than shot for kids

Study finds product is more effective in children under 5

February 15, 2007|By Dennis O'Brien | Dennis O'Brien,Sun Reporter

A nasal spray marketed by Gaithersburg-based Med- Immune Inc. appears to be more effective than flu shots in protecting children under 5, according to a major study published today.

"It's good news. We need it, we need a new flu vaccine for children," said Dr. Neal A. Halsey, director of the Institute for Vaccine Safety at the Johns Hopkins Bloomberg School of Public Health. He was not involved in the study.

Researchers gave either flu shots or the company's Flu- Mist nasal spray to almost 8,000 young children in 2004 and found that of the nearly 500 children who caught the flu, those given shots caught it twice as often.

The study, published in The New England Journal of Medicine, was funded by Med- Immune, which is trying to persuade the Food and Drug Administration to approve FluMist for use by children from ages 1 to 5. Researchers at the St. Louis University medical school say it's the largest pediatric study ever conducted comparing flu shots to the spray.

But some experts say that because researchers found increased hospitalization rates among the youngest children given the nasal spray, the results warrant closer scrutiny.

"There is an increased risk for certain children, but that has to be balanced against the benefits," said Dr. Joshua Sharfstein, Baltimore City health commissioner. "That's why we have an FDA."

Company officials, who have been struggling with competition from injected flu vaccines, called the results good news.

"We're very excited that these data are now out there," said Dr. Frank J. Malinoski, senior vice president of medical and scientific affairs for MedImmune.

Dr. Robert B. Belshe, the lead investigator and a professor of medicine and pediatrics at St. Louis University School of Medicine, said the spray works better in children because it's a weakened version of live flu virus. Injected vaccine is killed virus.

"The live vaccine gives a broader response, better than a flu shot," Belshe said.

Another advantage, he said, is that while shots stimulate antibodies in the blood, the nasal spray stimulates antibodies in the blood and the nose.

"Shots are good at boosting pre-existing immunity," he said. "But they don't work as well where there is no pre-existing immunity."

The FDA approved FluMist for people ages 5 to 49 in June 2003 but withheld approval for children under 5 because of previous studies linking it to wheezing problems among some youngsters.

A refrigerated version of FluMist was approved by the FDA in January and is due to replace the current frozen formula, which has been criticized for having difficult storage requirements.

Stock ailing

MedImmune's stock fell almost 9 percent last week after the company reported flat sales figures for 2006.

The company hopes to win FDA approval in May to begin marketing FluMist to children 1 to 5 with no history of wheezing or asthma, Malinoski said. FDA approval would open up a market of 14 million children now ineligible for the spray, he said.

MedImmune also hopes to one day win approval to distribute the vaccine to adults 50 and older but has yet to provide the necessary safety data to the FDA.

The study shows FluMist is safe for children from 1 to 5 with no history of wheezing or asthma, said Belshe.

But, he said, there is still a need for a safe vaccine for children under a year old. The study results show that 42 of the infants 6 months to 11 months old were hospitalized within six months of being given the nasal spray, compared with 18 hospitalization cases among infants given shots.

Belshe called the hospitalization rates "puzzling" and said many of the hospitalized children had problems largely unrelated to flu, such as diarrhea and lung infections. "We don't understand why that is," he said.

Data review urged

In an accompanying editorial, the New England Journal of Medicine editors called the results encouraging, but they recommend "further discussion and careful review" of safety data before FluMist is approved for young children.

"They're simply calling for caution, and that's appropriate," Belshe said. "We're talking about a very vulnerable population, children under 5."

In the study, 7,852 children ages 6 months to 4 years, 11 months received either the nasal spray or a flu shot at 249 hospitals and health care facilities in 16 countries. Those given active doses of the spray were also given placebo shots; those given real shots got a placebo spray. Influenza-like symptoms were then monitored, and nasal swab cultures were taken throughout the 2004-05 flu season.

Of the 491 children infected during the ensuing flu season, 338 had been given flu shots and 153 had received nasal spray, which translates to about 55 percent fewer flu cases. The spray was particularly effective at preventing the most common of the three strains of flu that cause illness each year, reducing cases of the H3N2 strain of flu virus by 79 percent.

"The efficacy was significant," Halsey said.

Flu season runs from December through April, according to the federal Centers for Disease Control and Prevention.

CDC reports show that this year's flu season has posed less of a threat than previous years, nationally and in Maryland.

"Essentially, its been a relatively mild season," said Curtis Allen, a CDC spokesman.

dennis.obrien@baltsun.com

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