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Health Wrap: Fading flu fighters

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Sep 23, 2005 (United Press International via COMTEX) -- Bad news, fellow flu phobics: Neither the shot to ward off the annual ailment, nor anti-virals that would be the first line of defense against an avian-flu pandemic, work as well as believed.

That's the bottom line from two studies in Thursday's Lancet, the prestigious British medical journal. The studies report:

-- Flu vaccines have only modest effectiveness in the elderly. They work somewhat better for old people in long-term-care facilities, but for the elderly in the general population inactivated flu vaccines were not effective in preventing flu or pneumonia.

-- Resistance to drugs used to treat people who contract the flu has increased by 12 percent in a decade. Worse, the highest rates of resistance were in Asia, where medical experts fear avian flu could mutate into a human pandemic at any time.

The bad news comes just days after the Centers for Disease Control and Prevention offered a brighter picture for flu-shot availability this year. Last year's last-minute shutdown of a European supplier set off a temporary shortage -- and long lines of elderly trying to get their shots.

Older people are at far greater risk of death from flu and related respiratory infections, so the news that flu vaccines are less effective for the elderly is especially troublesome.

The study -- led by Dr. Tom Jefferson of Cochrane Vaccine Field in Rome -- reviewed 65 studies of effectiveness of flu vaccines in those 65 and older. They found that while vaccines were not effective against flu or pneumonia, they prevented up to 30 percent of hospitalizations for pneumonia among elderly people living in the community.

Among those in long-term-care facilities, vaccines prevented up to 42 percent of pneumonia deaths.

Both those statistics make the case for getting the flu vaccine as a way of reducing the severity of the illness in the most susceptible population. But as a preventive, the flu vaccine clearly needs help.

"We need a more comprehensive and perhaps more effective strategy in controlling acute respiratory infections," Jefferson said in a statement, "relying on several preventive interventions that take into account the multi-agent nature of infectious respiratory disease."

Those interventions, he said, include "personal hygiene, provision of electricity and adequate food, water and sanitation."

None of that, however, could be expected to stave off an avian-flu epidemic if it mutates, as feared, into a form transmissible from human to human. That's why the increased resistance to anti-virals is so disturbing.

Those drugs, called adamantanes, have been used to treat influenza A for more than three decades and, until now, were thought to face little resistance.

But now, 10 years after the last report, things have changed for the worse. The new study, led by the CDC's Rick Bright, found that resistance had increased from 0.4 percent in 1994-1995 to 12.3 percent today. And in some Asian countries, drug-resistance frequencies topped 70 percent.

"We were alarmed to find such a dramatic increase in drug resistance in circulating human influenza viruses in recent years," Bright said. "Our report has broad implications for agencies and governments planning to stockpile these drugs for epidemic and pandemic strains of influenza."

Bottom line: "Amantadine and rimantadine will probably no longer be effective for treatment or prophylaxis in the event of a pandemic outbreak of influenza."

While more expensive anti-virals are available in the developed world, the study shows how quickly resistance can occur once they are in wide use.

This information is likely to send experts plotting a counterattack against avian flu back to the drawing board -- or the keyboard.

An analysis released a few weeks ago suggested that anti-viral drugs could stop a pandemic in its tracks if combined with early detection and prompt quarantine.

The analysis was based on a computer model by Neil Ferguson on the Howard Hughes Medical Institute, and determined that public-health officials would need to rush anti-viral drugs to the 20,000 people closest to the epicenter of an outbreak. Up to 3 million courses of the anti-virals might be needed to wipe out the epidemic, the computer calculated.

Copyright 2005 by United Press International.

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