Hacking a Path Through the Gnarly Thicket of Flu Remedies
Question: I’ve heard about a bunch of new tests to detect the flu. What can they do for me?
Answer: It’s true that five tests can now diagnose influenza in less than 30 minutes. That’s a lot faster than the two to seven days it takes to get results from a standard flu culture. Three of the tests are somewhat tricky to analyze, but two are so simple to read that the U.S. Food and Drug Administration allowed them to be excluded from the usual federal lab regulations. That means these two tests--Quickvue Influenza Test and Zstat Flu--can be used in doctors’ offices and analyzed by health professionals who aren’t necessarily lab technicians. For this reason, they are expected to be widely available.
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Q: So if I start feeling lousy and suspect the flu, I should go to my doctor and get tested, right?
A: Oh, so naive. It’s far more complex than that.
First, none of the rapid tests are as accurate as cultures. While they are very quick at detecting flu accurately, they fall short in ruling out the flu. In other words, if you test positive, you can be up to 99% certain that you have the flu, according to Timothy Uyecki, a medical epidemiologist in the influenza branch at the U.S. Centers for Disease Control and Prevention. But if you test negative, you’re not home free. Depending on the test, up to 25% of the cases identified as negative are actually influenza, Uyecki says.
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Q: OK, but if I do get a positive result, there’s a 99% chance I have the flu. Those are pretty good odds.
A: But the caveats continue, oh hopeful one. Only one of the five rapid tests can identify what variety of influenza you have--important information if your doctor wants to prescribe an antiviral medication to treat you. (More on that below.) One of the tests can only pinpoint influenza A. The other three tests just reveal whether you have some form of influenza, without telling you which kind.
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Q: So what are these quick flu tests useful for?
A: They’re best for nursing homes and other group-living facilities where flu can spread quickly among a population for whom the flu is dangerous--and where prompt treatment can save lives, not mere discomfort of the sort most people are likely to suffer. The tests can also help identify sporadic, off-season outbreaks, such as those on cruise ships. They’re useful because they can quickly identify who is ill and guide doctors in prescribing the most appropriate treatment.
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Q: So this whole testing-and-treating thing isn’t for me?
A: We didn’t say that. Getting tested can identify the flu as the cause of your cough, headache, achiness and fever. Ruling out the flu can also suggest (but not verify) the presence of a bacterial infection, for which your doctor may wish to prescribe antibiotics. And if you find out you do have the flu, you’re less likely to be prescribed unnecessary antibiotics, which can help breed resistant strains. And that’s not good for anybody.
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Q: What does a rapid test cost? Will insurance cover it?
A: The rapid tests cost $18 to $25 and are often covered by health insurance.
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Q: Are needles involved?
A: No, but throat swabs are, and one test needs only a few nasal secretions to check for influenza.
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Q: I’d rather avoid getting the flu in the first place, but I didn’t get a flu shot because the vaccine was said to be in short supply. Is it too late to get a flu shot now?
A: No, according to Nancy Cox, chief of the CDC’s influenza branch. But you shouldn’t wait much longer. The influenza season has gotten off to a slow start this year--a handy coincidence, since supplies of the vaccine were indeed tight early on. It should be widely available now.
During 14 of the last 18 winters, flu season did not peak until January or later. Since it takes 10 to 14 days after getting vaccinated to be protected, the odds still favor getting a flu shot, according to the CDC. The later it gets in January, the less sense a shot makes for those who are not at high risk for flu or its complications.
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Q: I saw a former “Seinfeld” actor on television advertising Relenza to treat flu. Should I take it if I get the flu this year? Will it shorten my sickness?
A: Maybe and maybe. There are two important catches: Flu antivirals must be prescribed within 48 hours of symptoms to be effective, and they don’t shorten the duration of illness very much, only shaving about a day off the natural course of the illness.
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Q: Argh. Do they at least treat all kinds of flu?
A: No, only the expensive ones do. One group of antivirals--amantidine and rimantidine--control influenza A, but have no effect on influenza B. (Both types of influenza occur each year during the annual flu epidemic. Vaccines against both are included in the annual flu shot. Since Oct. 1, about 75% of the positive cultures for flu have been influenza A, according to the CDC.) Both amantidine and rimantidine are available in tablets and syrup. But amantidine (Symmetrel) can be given to flu sufferers as young as 1 year old, while rimantidine (Flumadine) is approved for use only in adults. Symmetrel costs about $10 for a five-day supply. (A generic form costs just $2 for the same supply.) Rimantidine runs about $19 for a five-day supply.
That may seem like a good value, but be aware that these drugs can cause some undesirable neurological side effects (including nervousness, anxiety, difficulty concentrating and lightheadedness) and gastrointestinal problems. Studies suggest that these side effects occur more often with amantidine than rimantidine, but some people--those who don’t have other health risks--may prefer to take their chances with the flu.
A new generation of antivirals--the neuraminadase inhibitors--was introduced in 1999. Zanamivir (Relenza) and oseltamivir (Tamiflu) tackle both influenza A and B. Zanamivir is inhaled. Oseltamivir is taken by capsule. Both cost significantly more than amantidine and rimantidine, running an estimated $45 for a five-day supply of zanamivir and $53 for oseltamivir. They also seem to have fewer overall side effects than amantidine and rimantidine. Zanamivir has not been shown to be effective--and may actually be risky--for people with severe asthma or a lung condition called chronic obstructive pulmonary disease, according to the FDA. Oseltamivir also has some potential side effects, including gastrointestinal problems.
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Q: So why don’t these drugs cut the flu off at the knees?
A: Unlike antibiotics, which kill bacteria, antivirals don’t attack the virus itself. They simply prevent it from reproducing. Meaning these treatments usually shave only about a day off the natural course of a flu infection, something to consider when shelling out those dollars for antiviral medications.
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Q: So you’re telling me that, in order to test and treat my own case, I’d have to: (1) get to the doctor within 48 hours of getting symptoms; (2) take the test to verify that I have the flu and to determine which variety; (3) begin treatment immediately; (4) pay for the tests and medicine, which might be expensive; and (5) then endure, maybe, a slightly shorter and less severe illness.
A: Um, yes, that’s pretty much it.
