SAN DIEGO (AP) — An experimental new nasal spray not only takes the sting out of flu vaccination, it also appears to work substantially better than the standard flu shot.
Research presented Sunday shows that the spray vaccine did a surprisingly good job of protecting children from last winter’s flu bug — a strain that the regular flu shot was virtually worthless against.
“These results are very promising,” said Dr. Nancy J. Cox, a flu expert at the National Centers for Disease Control and Prevention in Atlanta.
The vaccine, called FluMist, is being developed by Aviron of Mountain View, Calif., which sponsored the latest study with the National Institutes of Health.
Finding a flu vaccine that avoids needles has obvious advantages for children and anyone else who hates shots. However, the latest data suggest that the spray approach may also provide more powerful protection against the flu.
Each year, the CDC, the World Health Organization and the U.S. Food and Drug Administration choose the three strains of the flu virus that appear most likely to be problems during the upcoming flu season. These are used to make the flu shot, which consists of killed viruses.
Going into last winter, the agencies chose wrong. They picked strains called A/Shenzhen, A/Wuhan and B/Harbin-like. The true culprit turned out to be a variety of flu called A/Sydney. Cox said the flu shot offered only marginal protection against this strain.
The nasal spray variety did much better, even though it contained the same three flu strains. A study of 1,358 children last winter showed that it was 86 percent protective against A/Sydney.
“What happened last year with A/Sydney is very exciting. This was a true test, and the vaccine passed with flying colors. Right now, it looks like the spray has advantages,” said Dr. Dominick Iacuzio of the NIH.
Even though the two vaccines were not compared head to head, researchers said they feel certain that the spray variety was substantially better, at least in last winter’s outbreak.
Results of the study were presented by Dr. Robert Belshe of Saint Louis University at an infectious disease meeting sponsored by the American Society for Microbiology.
In the study, 917 children received the spray vaccine, while 441 got dummy sprays. Two percent of the vaccinated children got the flu, compared with 13 percent in the comparison group.
Doctors believe the spray works better because it is made with a weakened virus rather than a dead one. When sprayed up the nose, the virus causes a harmless infection and produces new copies of itself.
“We believe the live vaccine induces a fuller complement of immune responses,” said Belshe. This gives the body an edge even against strains of the flu virus that are not included in the vaccine.
While the vaccine is likely to be aimed initially at children, Belshe said it probably will make sense for healthy adults as well. Researchers suspect that for the elderly, who are especially prone to serious flu infections, vaccination with both the spray and the shot may be better than either alone.
Aviron applied to the FDA for a license to sell FluMist in June, hoping to get the vaccine on the market by the 1999-2000 flu season. However, the FDA sent back the application last month, saying it needed more information on manufacturing issues.
J. Leighton Read, Aviron’s chairman, said Sunday the company now hopes to sell the vaccine for the 2000-2001 flu season. He said the company has not decided how much to charge for the spray, although it is likely to be more expensive than the flu shot.