Each year the flu puts more than 200,000 Americans in the hospital and causes anywhere from 3,000 to 49,000 deaths. With the exception of the H1N1 flu (also called swine flu) in 2009, most of these deaths occur in people over 65. But even for healthy younger people, the flu—characterized by high fever, body aches, headaches, and coughing—can be rough.
The CDC recommends that everybody over 6 months of age get vaccinated. It's especially important for people 65 and older, anyone who has a chronic condition (such as lung or heart disease, diabetes, cancer, or HIV infection), pregnant women, people on immunosuppressive drugs, and health-care workers. Mid-October through November is a good time to get it. Flu epidemics usually begin in January or February, and it takes a few weeks to develop immunity from the vaccination. Besides the familiar injection, a nasal spray flu vaccine is also approved for people under 50.
Still, the vaccine doesn't guarantee that you won't get the flu. An analysis of 31 studies covering 12 flu seasons, reported in Lancet Infectious Diseases this year, found that the most widely used flu vaccine in the U.S was just 59 percent effective, on average, for people 18 to 65. There were not enough data about older people, but there's reason to believe the vaccine may be even less effective in them.
Unfortunately, many media reports interpreted this to mean that the flu vaccine is no good. But the results weren't too surprising given that every year scientists have to predict months in advance which strains of flu virus will predominate in the next flu season in order to develop the vaccine in time (flu viruses are constantly mutating, even within a current flu season). If Mother Nature outwits the prediction—that is, if there isn't a close match between the strains of the virus selected for the vaccine and the actual circulating viruses—the effectiveness of the vaccine drops. Then again, as shown in a study in Vaccine in 2010, even when the match is incomplete, the vaccine still reduces the chance of getting infected and, if you do get sick, the severity of the illness—as well as hospitalizations from the flu and pneumonia (a life-threatening complication of the flu).
What's more, how well the flu vaccine works varies from person to person. It causes your body to develop antibodies against the virus—but people who are old and frail, are immune-compromised, and/or have a chronic illness don't have as robust an immune response to the vaccine and thus may not be as well protected. Being overweight may also decrease your vaccine response and make you less able to fight the flu if you do get infected. On the other hand, some research has shown that getting the vaccine annually may provide cumulative benefits in older people—more reason not to skip a year.
Your best shot at protection
Even though the flu vaccine won't keep everyone from getting sick, it lowers the risk and—this is key—helps prevent potentially fatal complications. It also reduces the number of people who can spread the virus (thus increasing what's called "herd immunity"). You must get it every year because the vaccine changes depending on the viruses circulating, plus its efficacy lasts only about six months. Some scientists believe we are only a few years away from a "universal" flu vaccine that you would need only once, perhaps with occasional boosters. But until something like that is available, the yearly shot is the best weapon we have against the flu.
There are only a few reasons not to be vaccinated—notably if you're severely allergic to eggs (since the vaccine is grown in eggs).
7 tips for flu season
Besides getting the vaccine, here is other flu advice to arm yourself with.
1. Follow the "six-foot rule" with anyone who seems sick. When someone with the flu coughs, sneezes, or even talks, the virus is expelled via respiratory droplets—and this is the most frequent way people become infected. The droplets rarely travel beyond six feet or so. If you take public transportation, you may not have this choice, however.
2. Wash your hands often—after you shake hands, for example, or handle an object someone else was using, such as a computer keyboard or phone. When you can't wash with soap and water, use an alcohol-based hand cleaner (with at least 60 percent alcohol). Skip antibacterial soaps—they're not good against viruses and may contribute to antibiotic-resistant bacteria.
3. When out in public, try to avoid touching your lips, nose, or eyes, unless you've just washed your hands. That's easier said than done since people tend to touch their faces without being aware—an average of 16 times an hour, according to a study done here at the UC Berkeley School of Public Health a few years ago.
4. Get the pneumococcal vaccine if you're 65 or older, are a smoker, or have a chronic disease such as diabetes, lung or heart disease, asthma, or HIV infection. This reduces mortality from the leading cause of bacterial pneumonia (a major complication of the flu) in older people. You need the vaccine only once, unless you got it before age 65, in which case you'll need a booster.
5. If you have flu symptoms, talk to your doctor about whether you should take a prescription anti-flu drug, such as oseltamivir (Tamiflu) or zanamivir (Relenza). When taken within the first two days of symptoms, they may shorten the duration and severity of the infection.
6. Don't fall for claims that dietary supplements (such as echinacea or vitamin C) or homeopathic remedies (such as Oscillococcinum and Nux vomica) can prevent or treat the flu. They can't. One possible exception is vitamin D, which plays an important role in the immune system. In a 2010 Japanese study in the American Journal of Clinical Nutrition, schoolchildren given vitamin D supplements (1,200 IU a day) throughout winter were 40 percent less likely to develop the flu than those given a placebo. Other recent studies have shown that healthy adults with higher blood levels of vitamin D were less likely to develop viral respiratory infections. Still, more research is needed.
7. If you do get the flu, stay home so you don't infect others (typically, adults are contagious for about a day before symptoms begin and for about five days after; children longer). If you have to go out and need to cough or sneeze but have no tissue, do it into your sleeve or the crook or your arm, rather than into your hand or the air.
Vaccine myths vs. realities
Many people avoid the flu shot for various reasons. Here are some of their concerns—and our counterarguments.
"I'm afraid it will give me the flu": This is not possible—the virus in the shot is inactivated. Mild side effects are possible, though, including soreness at the injection site and some low-grade fever and mild aches for one to two days after. Rarely are there severe allergic reactions. Nasal spray vaccines (not given to older people) contain weakened viruses but do not cause the flu either.
- "It might weaken my immune system": No way—the vaccine teaches your immune system to combat the flu virus.
- "It will give me Alzheimer's disease, or my child autism": No, it won't. Those are myths.
- "I don't like needles": Most people don't, but be brave—looking away helps. Soon there will be vaccines given via micro-needles that cause no pain.
Explore further: The Medical Minute: New flu vaccine recommendations