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6 Common Misconceptions about the Flu-and Flu Shots


MALTA—Efforts to create a universal flu vaccine, one that would do away with the annual reformulations, is a hot topic these days in the infectious disease community. But in the bigger picture of reducing flu transmission—and reducing the thousands of deaths it causes in the U.S. each year—there is a big leap forward that could be taken with already available tools. Researchers and public health officials these days agree that a vast improvement now would simply involve inducing more people to get existing annual flu shots.

Popular confusion about the influenza vaccine—how effective and how safe it is—is part of a broader misunderstanding about the flu in general, noted a panel of doctors and health workers on Tuesday at the European Scientific Working Group on Influenza's annual conference in Malta.

Here are six common misconceptions about the flu, according to the panel—supported by the latest research:

1. Influenza? No big deal, it's just the flu.

"We are always underestimating the disease," Roman Prymula, of the University Hospital Hradec Kralove in the Czech Republic, said on Tuesday. Although a minority of the adult population comes down with the seasonal flu each year, he said, the number of deaths in which influenza plays a part is vastly underreported. By some estimates, he suggests, only about a quarter of deaths from the flu are reported as such—the remainder are often categorized as due to conditions such as cardiovascular complications. The U.S. Centers for Disease Control estimates that some 36,000 people die from the flu—or influenza-related causes—each year.

2. Me? I'm not in a high-risk group.

The seasonal flu is a particular threat to the elderly, whose immune systems are not always up to the task of fending off the infection—and who are more likely to have underlying medical conditions that make them more vulnerable. But the recent experience with the H1N1 2009 pandemic was a reminder that some strains of the flu can be more deadly for the otherwise healthy, who are in their prime—25 to 50 years old.

3. Flu shot? It'll probably give me the flu.

"You can't get it from an inactivated vaccine," said Betty Voordouw, of the Medicines Evaluation Board in the Netherlands. She noted that it's odd that patients typically accept that other vaccines will cause a slight fever, and even take that as a sign that they are working correctly with the immune system. But when it comes to the flu shot, at any sign of sickness, many people assume the shot has given them the full-blown flu.

It's especially tricky in the real world, as flu shots are usually given about the time respiratory and other infections are starting to spread, said Arnold Monto, of the University of Michigan. And, he noted, "We have a lot of other respiratory illnesses out there that look like the flu." Many gastrointestinal viruses go masquerading as "the flu," he said, because it "has become a polite way of saying, 'I've got diarrhea,' so we have this kind of confusion going on when you hear people say, 'I got the flu in spite of the flu vaccine.'" As a health professional, he adds, that he and others "need to try harder to explain just what it is that we're preventing."

The most likely side effect of the flu shot? A sore arm, Monto said, which is reported in about 40 to 50 percent of people in controlled trials. And if you are getting a live attenuated vaccine, the next most likely side effect is a mild stuffy nose.

4. I got my flu shot last year, but I got the flu anyway—it probably doesn't even have the right strains in it.

"In the past, we may have oversold how well the vaccine do work," Monto said. "We have, as I categorize it, a good vaccine—not a great vaccine." Previous studies, which were conducted largely among members of the U.S. military showed a 70 to 90 percent protection rate. But recent studies hint that the more standard rate is probably closer to 70 percent, Monto noted, adding that he would really like to see a more effective vaccine for young children and the elderly.

Today, there "is really a word wide surveillance system," said Bruno Lina, of the University of Lyon. And even though the strains to put in the vaccine for the northern hemisphere's flu season have to be selected in advance, in February, so far researchers have done a pretty good job of predicting correctly which strains will circulate some eight months later.

Take a cue from computer engineers, Lina said, adding: "When people buy antivirals for their computer, the computer says, 'Bing! You have been protected.' I wish vaccine manufacturers could prepare something like that." The problem with any preventive measures, added Monto: "If you don't get something, you don't know that you've been exposed—and you don't know that you've been protected."

5. Adjuvants and other ingredients of the shot are dangerous.

In pure scientific logic, as Voordouw pointed out, "you can never say that anything is safe." Adjuvants, which boost the immune response and thereby require less of the virus, have been controversial in the U.S., but not so much in Europe and beyond. Even with adjuvants, which also act as a preservative, "I think the benefits of adding an adjuvant to an influenza vaccine will far outweigh the risks," she said.

It can be tough to accept an option that carries any risk at all, Lina said, especially in the U.S. where the public seems insistent at times on zero risk. That sort of logic, he notes, from a public health standpoint "is stupid behavior—because you're dealing with disease, and you have to weigh the benefits and the risks." And, he acknowledges, that can be a difficult exercise for people unaccustomed to very consciously accepting small amounts of risk for a much larger benefit—both to themselves and the people around them.

6. There's no treatment for the flu, so I'll just take some aspirin.

The flu is tough to treat not because we don't have the right medicines (Tamiflu has been a successful antidote so far), but because it is actually a relatively short-lived illness. As miserable as it can be, most adults clear the infection on their own in five days. But because they often wait two to three days to see the doctor, and Tamiflu clears the virus in three days, some times it wouldn't make much of a difference. But, as Lina points out, when you're miserable with the flu, even a one-day reduction in the sickness is a huge relief.

Of course, for people in high-risk groups, early treatment reduces the need for intensive care, along with overall mortality. In places such as nursing homes, where an outbreak of the seasonal H3N2 flu can kill as much as 10 percent of the population, examples in France have shown that even giving Tamiflu as prophylaxis has been shown to cut off the epidemic. But for normal circumstances, these antivirals should be saved for such pandemics—for when we don't have other means of prevention. For the seasonal flu, though, there just happens to be a relatively safe and pretty effective way of avoiding it already, which is just a quick needle jab away at your local pharmacy, workplace or doctor's office.


The views expressed are those of the author and are not necessarily those of Scientific American.

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