Each year the influenza virus sickens between 9 million and 49 million Americans, sends hundreds of thousands to the hospital, and causes anywhere from 12,000 to 79,000 deaths. 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 everyone over six months old get vaccinated against the flu. It’s especially important for people 65 and older, anyone with a chronic medical condition (such as lung or heart disease, diabetes, HIV infection, or cancer), obese people, pregnant women, people on immunosuppressive drugs, and health care workers.
Mid-October through November is a good time to get the flu vaccine—but getting the shot later, such as in December or even January, is still better than not getting it at all. Flu epidemics usually begin in January or February (and tend to end by April), and it takes a couple of weeks to develop immunity from the vaccination. Getting vaccinated earlier than October—say, in August or early September, when the vaccine becomes available—isn’t ideal because the protection (which lasts on average about six months) might be waning while influenza is still in your community. Besides the familiar injection, a nasal spray flu vaccine is also approved for people ages 2 through 50.
Your best shot at protection
The flu vaccine doesn’t guarantee that you won’t get sick from the flu; its effectiveness has averaged 45 percent over the last 10 years (with a high of 60 percent in 2010). That’s much less than the protection provided by the measles vaccine, for instance, which is 93 to 95 percent effective. But it’s also not 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. This was seen in the 2017-2018 flu season, an especially severe one worldwide and the deadliest in the U.S. in decades. The CDC determined that the vaccine that season provided only about 40 percent protection.
Still, even when the match is incomplete, the vaccine reduces the chance of getting infected and, if you do get sick, the severity of the illness. Moreover, it reduces your risk of being hospitalized for the flu and of developing pneumonia, a life-threatening complication.
The vaccine also reduces the number of people who can spread the virus, thus increasing what’s called “herd immunity.” Older adults in particular appear to benefit from this: In a 2015 study in Clinical Infectious Diseases, for example, researchers examined data collected from more than 3 million Americans over eight years and estimated that in counties where at least one-quarter of adults under 65 were vaccinated, older adults had a 20 percent lower chance of developing the flu compared to counties with the lowest vaccination rates in adults under 65. Older adults who were vaccinated against the flu benefited the most—suggesting that “community-wide vaccination may amplify the benefits of individual vaccination,” as the authors put it.
There are only a few reasons not to be vaccinated—notably if you have a severe, life-threatening allergy to the flu vaccine or any ingredient in it, which might include gelatin or antibiotics. People with an allergy to eggs, who were long told to avoid the flu vaccine (which is grown in eggs), are now advised by the CDC and other health authorities to get vaccinated—though the CDC says that people with a history of severe egg allergy should do so in a medical setting, where they can be closely monitored for a reaction.
If you’re 65 or older, ask about getting the high-dose flu vaccine (Fluzone). A 2014 study in the New England Journal of Medicine, which included nearly 32,000 people in that age group, found that the high-dose vaccine was more effective in reducing lab-confirmed influenza than the standard flu vaccine. Both vaccines protect against several strains of influenza, but the high-dose one is four times stronger and induces a higher antibody response (this response declines with age, which is why older people get less protection from the regular vaccine). Another option approved specifically for people 65 and older is Fluad, which combines the regular-strength influenza vaccine with an adjuvant—a substance that helps promote a more robust immune response.
Scientists are working to develop a “universal” flu vaccine that you would need only once, perhaps with occasional boosters. The NIH announced in April 2019, in fact, that it is beginning a clinical trial of one experimental candidate (given the tongue-tying name H1ssF_3928), which is designed to target a portion of the influenza virus that varies little from strain to strain. But until a universal vaccine is available, you must get the shot (or nasal spray) every year.
7 tips for surviving flu season
- Follow the “six-foot rule” with anyone who seems sick with a respiratory illness. (If you take public transportation, you may not have this choice, of course.) 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. It’s uncommon for the droplets to travel beyond six feet or so. Wearing a surgical mask won’t protect you from getting infected by flu droplets (only an N95 respirator mask can do that); but if you are sick with the flu, it can help keep you from infecting others.
- 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. You can either wash with soap and water or use an alcohol-based hand sanitizer (with at least 60 percent alcohol—ethanol, isopropanol, or both).
- 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 of it—an average of 16 times an hour, according to a study done at the UC Berkeley School of Public Health about a decade ago.
- Get the pneumococcal vaccine if you’re 65 or older, are a smoker, or have a chronic condition such as diabetes, lung or heart disease, asthma, or HIV infection. This reduces mortality from a leading cause of bacterial pneumonia (a major complication of the flu) in older people.
- If you have flu symptoms, ask your doctor whether you should take a prescription antiviral drug, such as oseltamivir (Tamiflu), zanamivir (Relenza), or baloxavir marboxil (Xofluza). When taken within the first two days of symptoms, they reduce the infection’s duration and severity.
- Don’t fall for claims that dietary supplements (such as echinacea, Airborne, and vitamin C) or homeopathic remedies (such as Oscillococcinum and nux vomica) can prevent or treat the flu (or any infectious disease). They can’t.
- If you do get the flu, stay home so you don’t infect others (and remember the six-foot rule there, too). Typically, adults can infect others starting 24 hours before symptoms begin, and they are most contagious for three to five days after. Children and obese people may remain contagious 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 of your arm, rather than into your hand or the air.
A final word
Many people avoid flu shots for various misguided reasons. Don’t be one of them. Don’t believe claims the shot will give you the flu (at most you might have some mild side effects like minor aches and pains) or that it will weaken your immune system (the vaccine actually teaches your immune system to combat the flu virus). It won’t give you Alzheimer’s disease or your child autism—these are myths. What if you don’t like needles? Few people do, but looking away helps. Within the next few years, it’s expected that there will be vaccines given via microneedles that may cause less (or no) pain.
This article first appeared in the October 2019 issue of the UC Berkeley Wellness Letter. An earlier version was published in November 2012 and updated in December 2017.
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