FDA clears first nasal mist flu vaccine

Wednesday, June 18, 2003

WASHINGTON -- A flu vaccine that is the first to be delivered by a squirt up the nose instead of a needle in the arm has been approved by the Food and Drug Administration for healthy people from 5 to 49.

The vaccine, called FluMist, was approved by the FDA even though it was given only a tentative endorsement by an advisory panel last the December. The panel said the drug would not be appropriate for people who most need vaccine protection from influenza: toddlers, the elderly and people with asthma or other chronic diseases.

For children from 5 to 8, the approval requires two doses of FluMist six weeks apart. Patients from 9 to 49 need only one dose, the agency said.

The safety and effectiveness of FluMist has not been proven for people 50 and over. The FDA encouraged those patients to get the injected flu vaccine.

FluMist was not approved for children under 5, because in clinical trials researchers found that young children treated with the nasal mist vaccine had a higher rate of asthma attacks and wheezing within 42 days of the vaccination, compared to children who received a placebo.

Approval of FluMist achieves a goal of many flu experts: a needle-free alternative to the annual shot. Some believe this may encourage more people to become vaccinated against flu.

FluMist contains each of the three influenza live virus strains expected to be active during the 2003-2004 flu season. These include two types of influenza A, which causes severe illness, and one type of influenza B, which causes a milder form of the disease. The live virus in the vaccine has been modified and weakened so that it produces immunity without causing illness.

Influenza is the cause of 36,000 deaths annually in the United States. Most of the victims are patients with other health problems, children under 2 and people over 65.

"This new vaccine provides another option for protection against influenza and will potentially increase the availability of the injected killed virus vaccine for those at highest risk," Dr. Mark B. McClellan, the FDA commissioner, said in a statement.

There have been vaccine shortages at the beginning of some flu seasons in the past, because there are few manufacturers of the drug and the formula must be changed each year to match the changes in the circulating virus.

FluMist is manufactured by MedImmune Vaccines, Inc. of Gaithersburg, Md. A company spokesperson said that the firm is now taking orders for the drug and that four to six million doses will be available by October, the start of the flu season. The company said FluMist will cost about $46 a dose. This is more than twice the typical cost of injected flu vaccine.

The company in July 2001 sought FDA approval to market FluMist for children, but FDA's advisers said the drug had not been proven safe for them. MedImmune revised its application and it was endorsed, with reservations, by the advisers last year.

Clinical studies showed that although FluMist provided flu protection for 93 percent of the 1,600 healthy children tested, there was a 1.5 percent incidence of asthma attacks or wheezing among children under 5.

The advisory panel agreed with MedImmune's decision to limit childhood use of FluMist to those over 5.

Studies showed that FluMist did not provide the same flu protection for adults from 50 to 64 as vaccinations. For adults from 18 to 49, the studies suggested FluMist reduced severe illness.

An FDA statement said FluMist should not be given to persons with compromised immune systems, such as patients with AIDS, cancer or organ transplants. The agency also said that the safety of the nasal vaccine has not been demonstrated for patients with asthma or some other reactive breathing diseases.

People with underlying medical conditions who would be most seriously affected by a flu infection should receive the injected form of vaccine, the agency said.

FluMist also is not recommended for people who are allergic to eggs or who have demonstrated an earlier allergic reaction to flu vaccine.

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