Gift exchange that’s hard to avoid: the flu

Just how effective are flu vaccinations?

Scripps Howard

Chances are, the flu will become part of the sharing among family and friends this holiday season.

In fact, outbreaks of the winter’s nastiest viruses typically get rolling around this time of year largely because we spend more time indoors, in crowds and among different people than we normally hang with — a perfect environment for swapping germs.

Several recent studies suggest that with the flu, timing is everything.

One recent report, from the National Institutes of Health, found that the flu virus actually has an outer shell that allows it to endure cold weather, but turns into a butterlike consistency when it enters a warm moist respiratory tract.

So, flu virus predominates when the weather’s relatively cold and dry, and melts away in the spring and summer, when conditions are warmer and wetter. The season peaks at different times around the nation, but more often than not, takes off in January or February.

This flu season appears more likely than in the past few years to catch people with their immunity down.

A survey released last week by the National Foundation for Infectious Diseases found that fewer than 30 percent of American adults have gotten a flu shot this fall, even though federal guidelines now consider pretty much everyone but healthy adults under age 50 to be at high risk from the illness.

But what if flu shots were offered, free, to everyone? The province of Ontario in Canada has been doing just that for anyone over the age of 6 months, since 2000. Yet the vaccination rate still hovers at under 40 percent.

Even so, compared to other provinces that continue to try and vaccinate only groups that are at high risk of death or complications from flu, Ontario scores better in terms of flu-related deaths, hospitalizations and emergency room and doctor’s office visits, according to researchers at the Institute for Clinical Evaluation Sciences in Toronto.

With several months of flu season to go, it’s still worthwhile to get immunized.

If you do, it’s better to get that shot in the morning, particularly if you’re male. Studies done at the University of Birmingham, England, and published in July, found that college-aged men and senior men had a stronger immune response to shots given in the morning than in the afternoon. There was no similar effect for women. The study appeared in the journal Psychophysiology.

More recently, researchers at Stanford University presented evidence from fruit flies that shows the natural immune system is stronger at night than during the day.

Those findings may support the findings from England. A challenge to the immune system presented in the morning may be well timed to generate antibodies in the evening.

Researchers are also experimenting with how much flu vaccine is really needed. For instance, researchers from Walter Reed Army Medical Center ran an experiment in which they gave half doses to some adults and full doses to others, among a group of nearly 600 healthy adults aged 18 to 64.

Their report in a recent issue of the Archives of Internal Medicine showed that people getting the half dose responded about as well as the full dose subjects until after age 50.

The test confirms that if there should be a shortage of flu vaccine, particularly when some deadly pandemic strain is looming, that the young and middle aged could get by with a split dose.

However, the weakening of the immune system after 50, and particularly in the 70s and beyond, poses a particular problem for controlling flu among the elderly, who, along with toddlers, are most at risk from the flu.

Researchers are increasingly finding reasons to doubt that annual flu shots do as much as once thought to protect seniors from the flu, and from flu’s deadliest consequence, pneumonia.

The most recent study, involving more than 3,500 patients aged 65, found no difference in pneumonia rates among those who got a flu shot and those who didn’t. The three-year study by doctors at the Group Health Center for Health Studies was published in The Lancet in August.

While flu shots are still worthwhile for this age group, the researchers note that either bigger doses or stronger vaccines may be needed to protect very frail seniors.