With seasonal flu shots plentiful and H1N1 vaccines expected soon, early vaccination is urged

Washington -- Federal health officials say there is plenty of vaccine for seasonal influenza this year, and are urging physicians and patients to use it.

Authorities expect a vaccine for influenza A(H1N1) to be ready by mid-October. On Sept. 15, the Food and Drug Administration approved applications from four manufacturers to make the vaccine.

Health officials say this is one of the most complicated influenza seasons in memory -- involving two flu viruses, one of which has sparked a pandemic. But their message is still simple -- get vaccinated.

"Flu is already the most unpredictable of all the infectious diseases. We know that this year we are in uncharted territory," said Centers for Disease Control and Prevention Director Thomas Frieden, MD, MPH.

Even as H1N1 grabs the headlines, it's important that physicians and the public not overlook the seasonal flu, health officials stressed. Each year 5% to 20% of the population contracts seasonal flu, about 200,000 are hospitalized with flu-related complications, and 36,000 die.

About 115 million doses of seasonal flu vaccine are available, with about 40 million doses already shipped to physicians' offices and clinics.

"This is a serious disease," Health and Human Services Secretary Kathleen Sebelius said at a Sept. 10 news briefing. "Getting vaccinated for seasonal flu right now is good advice."

Sebelius said vaccination rates for health care professionals remain too low -- only about 40% are immunized for the flu each year. "We would like health care workers to go to the front of the line."

AMA Immediate Past President Nancy H. Nielsen, MD, PhD, is urging every physician to get a shot. "It's important for all physicians to be involved in helping patients make sure they are protected. And if we ourselves do not get vaccinated, we are not taking care of patients."

Last spring's arrival of the H1N1 virus caught everyone by surprise. Had that strain emerged earlier, it would have been addressed as a component of this year's seasonal flu shot, Sebelius said.

The H1N1 virus never disappeared during the summer -- as the seasonal flu virus typically does -- and is spreading. "We are seeing as much flu in early September as we would normally see at the height of flu season," Dr. Frieden said.

But health officials said they are optimistic about the nation's response to H1N1. The approval of four manufacturers to make H1N1 flu vaccine means state health departments should begin receiving shipments by Oct. 15 for distribution to doctors.

Promising results from clinical trials indicate that one dose of the new vaccine, rather than two, provides protection for most healthy adults. The trials also showed that the vaccine provoked a robust immune response just eight to 10 days after immunization, said Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, which is running some of the trials.

In addition, there were no safety concerns, Dr. Fauci said. The only side effects were normal swelling and redness at the injection site and a runny nose or nasal congestion from the nasal spray version of the vaccine.

Officials had predicted that full immunity might not occur until about a month after inoculation and then only after two injections. Sebelius said the trial findings have improved this scenario. "It shortens the window of worry, and more people can be protected much earlier."

The new data suggesting one dose of H1N1 vaccine will be effective mean the expected supply of about 195 million doses will go much further than originally thought. Immunization efforts being planned by state health departments also will be simplified if there is no need for everyone to get a second shot.

But young children, a priority group to receive vaccine, still may need two shots to provide immunity. Trials including children and pregnant women began later than trials in healthy adults. Results are not yet available.

Although vaccination is the first line of defense against both influenzas, the antivirals oseltamivir (Tamiflu) and zanamivir (Relenza) may be helpful in treating flu patients who are hospitalized, according to guidance released Sept. 8 by the CDC. The antivirals can reduce severity of symptoms when started within 48 hours of the onset of illness.

But the supply is not infinite. Federal officials are asking physicians to reserve the antivirals for the sickest patients and those at the highest risk for severe illness from either seasonal flu or H1N1. Most people who contract influenza-like illnesses this season will recover with rest and fluids and won't need an antiviral, said Anne Schuchat, MD, director of the CDC's National Center for Immunization and Respiratory Diseases.

Judicious use of antivirals also could help reduce the chances that the H1N1 virus will develop broad resistance to the drugs, the CDC said. Some cases of antiviral resistance to H1N1 already have been reported.

If patients are sick enough to need antivirals, physicians should not wait to confirm the viral strain, Dr. Schuchat said.

"Beginning treatment within the first 48 hours of symptoms can really help with the outcome."