THURSDAY, Feb. 21 (HealthDay News) -- A U.S. Food and Drug Administration panel on Thursday approved the inclusion of three new flu strains in next year's batch of flu vaccine, in an unusual move that health officials hope will avoid the shortcomings of this year's vaccine.

Typically, only one or two strains are changed each year, and flu vaccine manufacturers need a long lead time, about eight months, to complete the entire production process for the 100 million doses due by the fall.

"We have things in the pipeline, but we are not in a situation we'd like to be this time of year with working seeds ready to go," Tony Colegate, of Novartis Vaccines and Diagnostics, told the FDA panel, according to Dow Jones Newswire. "We think this will be a very, very difficult year."

The expansion of flu strains for next year comes during a current flu season that has not been easy so far.

This year's flu shot has missed its mark badly, and the end result has been widespread or regional flu activity in virtually every state. Many of the infections are being caused by strains not covered by this year's vaccine, U.S. health officials have said. And some strains are becoming resistant to a common antiviral medication.

The U.S. Centers for Disease Control and Prevention first reported last week that this year's flu vaccine doesn't match two of the three strains of influenza currently circulating in the United States.

"Clearly, there is influenza going around in a lot of states," said Dr. Peter C. Welch, an infectious diseases expert at Northern Westchester Hospital in Mt. Kisco, N.Y. "Part of the issue is that the vaccine which was produced this year is not the most effective vaccine that we've had for influenza."

Because the influenza virus constantly changes structure, the vaccine must be reformulated every year. The World Health Organization announced last week its recommendations for next year's flu vaccine, which includes protection against the H3N2 strain and other strains not in this year's vaccine.

And the FDA panel on Thursday followed the WHO lead. The new flu strains include Brisbane/10, a version of the H3N2 flu; a second new Type A strain known as H1N1/Brisbane/59, and a newer Type B/Florida strain.

The virus strain most common in the United States right now is the influenza A H3N2 strain, and it's a strain not included in this year's vaccine. Also, this year's vaccine is not well-matched against influenza type B.

Complicating matters, some of this year's influenza type A virus is showing resistance to the antiviral drug Tamiflu. Overall, 8.1 percent of the influenza type A viruses tested by the CDC were resistant to Tamiflu. In past years, less than 1 percent of the viruses have been resistant to the drug.

The composition of a flu vaccine is not an easy prediction at best, Welch said.

"Although these are educated guesses, they clearly are guesses," he added. "Sometimes, they guess right. Sometimes, they guess wrong. This year, they didn't guess well. Sixteen out of the last 19 years they have guessed pretty well."

For the week ending Feb. 9, widespread flu activity was reported by 44 states and regional activity was reported by five, for a total of 49, according to the CDC's latest tally. During the three most recent flu seasons, the number of states reporting regional or widespread activity peaked at 41 to 48 states.

Ten children, ranging in age from 4 months to 14 years, have died from influenza so far this year, the CDC also reported. During the last three years, flu-related deaths among children have ranged from 46 to 74.

Even though this year's vaccine isn't a good match for most of the circulating flu virus, CDC officials continue to recommend that people get inoculated. The reason: The vaccine still offers partial protection and can reduce the risk of flu-related complications.

An estimated 5 percent to 20 percent of the U.S. population suffers from the flu each year. More than 200,000 people are hospitalized from flu complications, and about 36,000 people die from the disease. Some people, such as older individuals, young children, and people with certain health conditions (such as asthma, diabetes or heart disease), are at high risk for serious flu complications, according to the CDC.

More information

The U.S. Centers for Disease Control and Prevention has more on the flu and the flu vaccine.

TUESDAY, Feb. 12 (HealthDay News) -- Two new studies try to answer one of the most pressing questions in critical care medicine: How much pressure should be applied to keep open the partially collapsed lungs of people being treated for the deadly condition called acute respiratory distress syndrome?

Unfortunately, that question has not been definitively answered. Two experts have differing views on what the outcomes, which were not clear-cut, might mean. To one, the answer from the studies being published in the Feb. 13 issue of the Journal of the American Medical Association is that higher positive end-expiratory pressure (PEEP) is better, but the exact amount of pressure must be adapted to each person. Yet another contended there was no proof of the value of higher PEEP.

The results should have some impact on medical practice, pushing intensive care units toward use of higher PEEP levels, based on a patient's needs, said Dr. Derek C. Angus, chairman of the department of critical care medicine at the University of Pittsburgh, and author of an accompanying editorial.

The two research teams, from Canada and France, used different techniques to determine those needs. "The Canadian study titrated PEEP based on the reading of how oxygenated the lung tissue was," explained Angus. "The French relied on more sophisticated measures. One was slightly simpler than the other, but both were trying to convert a set of principles into a recipe to titrate PEEP, so you end with a different measure for each person."

Neither formula had a major effect on the death rate. In the French study of 767 people treated for acute respiratory distress syndrome (ARDS), the hospital mortality was 39 percent among those who got conventional treatment using relatively low PEEP, and 35.4 percent among those who got higher PEEP based on individual calculations. The comparable figures for the 983 people treated for ARDS in the Canadian study was 40.4 percent for those getting conventional treatment, and 36.4 percent for receiving higher PEEP based on individual characteristics.

"While neither study changed overall mortality much, both made moves in the right direction," Angus said. "There was a trend toward lower mortality in both studies [with higher PEEP]. In both studies, there was clearly improved oxygenation. And both reduced the need to use rescue therapies, last-ditch attempts to use experimental, sometimes crazy, things to keep patients alive."

Another expert was more cautious.

"I don't think the results of the Canadian study would be enough to change practice in a systematic way," said Dr. Leonard C. Hudson, head of the division of pulmonary and critical medicine at the University of Washington.

But the Canadian researchers begged to differ.

Their results do offer support for a change to higher PEEP levels, said Dr. Gordon H. Guyatt, a professor of medicine at McMaster University in Toronto and a member of the Canadian research team.

"It is not clear that higher PEEP is better, in terms of a lower mortality rate, but it is very likely that higher PEEP is at least as good," Guyatt said. "There is an established way of treatment using lower PEEP. We now have shown that using higher PEEP is at least as good, and perhaps better. Clinicians who prefer using a higher PEEP can now feel comfortable in doing so."

ARDS develops in people who suffer major injuries or who are critically ill with diseases such as pneumonia or bacterial infections. Fluid builds up in the lungs until breathing becomes more and more difficult. In treatment, air is forced into the lungs. A marked feature of the two studies was a continuation of the trend to change the pattern of forced breathing, with the number of breaths per minute doubled, and the tidal volume, the amount of air forced into the lung with each breath, halved.

The new studies were aimed at settling a debate about how much PEEP should be applied at the end of each breath, enough to prevent lung collapse, but not so much as to damage lung tissue.

The basic point of the Canadian study to Hudson was tidal volume. "To me, what it says is that probably the most important thing about lung protection is making sure the tidal volume is low," he said. "That allows you to use as high a level of PEEP as you want."

Angus had a quite different view, saying that individually calculated higher PEEP levels were the decisive factors. "It's pretty hard to argue that we should continue to do what we have been doing," Angus said.

More information

For more on ARDS, head to the U.S. National Library of Medicine.

TUESDAY, Feb. 5 (HealthDay News) -- Schering-Plough's Asmanex Twisthaler, an inhaled steroid designed to prevent asthma attacks, has been approved by the U.S. Food and Drug Administration for children as young as 4 years, the Associated Press reported.

In March 2005, the drug was approved to prevent asthma attacks in adults and children aged 12 and older. The newly approved dose for youngsters is half the adult dose, the AP said.

Asthma is the most common chronic condition among children, affecting as many as 10 percent of Americans under 18. It's responsible for more than 14 million missed school days and close to 1 million visits to the emergency room each year, the wire service said, citing the Asthma and Allergy Foundation of America.

The Twisthaler doesn't have a propellant, but is inhaled when a user places the device in the mouth and breathes.

As with other corticosteroid inhalers, Asmanex has possible adverse effects including stunting a child's growth rate, causing oral fungal infections, and increasing users' risks of glaucoma or cataracts. More frequent side effects may include headache, sore throat, respiratory infection, upset stomach, and pain of the muscles, bones and back, according to AP.

More information

The FDA has more about this drug.