12 Cold & Flu Myths

As cold and flu season wears on, it's pretty likely you or someone in your family have played host to one of the unpleasant respiratory viruses making the rounds. Getting rid of these unwelcome "guests"—or avoiding them altogether—starts with knowing which strategies and beliefs are helpful, and which aren't. Here, we set the record straight.

Why it's not true: The viruses contained in flu shots have been killed (the pros say they been "inactivated"), which means they really can't cause infection. Getting a flu shot may cause symptoms that feel like the flu, though, admits Susan Coffin, M.D., medical director of infection prevention and control at The Children's Hospital of Philadelphia. "Most often, people misattribute the achy side effect that can sometimes follow the flu shot with the onset of the flu itself," she says. "There are also so many other respiratory viruses floating around out there that you could catch one after you get the flu vaccine, and it may seem as though the shot caused it. It hasn't."

Unlike the flu shot, the nasal spray flu vaccine (Live Attenuated Influenza Vaccine, or LAIV, also known as FluMist) does contain live viruses. The viruses are weakened, though, and shouldn't cause the flu, Dr. Coffin says. Mild reactions from the nasal spray flu vaccine may include runny nose, nasal congestion or cough, chills, tiredness and weakness, sore throat, and headache. These side effects are mild and clear up quickly, especially compared with the symptoms of the flu, she says.

Why it's not true: Most people know by now that only a cold virus causes a cold. But many cling to the belief that going outside not properly dressed (or with wet hair) on a cold day will worsen the symptoms of a cold virus. This is also untrue. "I think this comes from people noticing that more people get sick during the colder months, and that is true," Dr. Coffin says. The real reason? Proximity. People generally spend more time indoors, closer together, and touch hands or come in contact with coughing and sneezing more. So viruses tend to "make the rounds" and strike more people. But being in the cold weather will only make you colder (and perhaps make your nose and eyes run a little more), not sicker.

Why it's not true: Phlegm is the thick, sticky mucus that drips down the back of the throat when a person has a cold. Drinking milk may make phlegm thicker and more irritating to the throat than it would normally be, but it doesn't cause the body to make more phlegm," says James Steckelberg, M.D., consultant in the division of Infectious diseases and a professor of medicine at Mayo Medical School in Rochester, Minnesota. That's a myth. In fact, Dr. Steckelberg recommends that cold sufferers drink or eat dairy products such as cream-based soups, ice cream, pudding, or milk, as they are soothing on sore throats and provide calories they otherwise might not eat while they're feeling so lousy.

If you find that you or your child develop sinusitis (inflammation of the sinuses) and/or ear infections after consuming dairy products, a dairy allergy may be involved. Discuss your suspicions with your doctor or with your child's pediatrician.

Why it's not true: If you have a cold, you're most contagious for the first 2 to 3 days, whether you have a fever or not, according to the National Institutes of Health. "Sometimes, at our house, the fever is 'the Grand Finale' of everyone's cold—it shows up at the very end," says Mary Linda Swiatek, mother of two children, ages 14 and 12, in Lake Mary, Florida. Swiatek says she has long been aware that contagiousness can precede visible symptoms. The contagious phase of a cold virus is usually over by day 7 to 10. Adults and older children with colds generally have a low fever or no fever. Young children, though, often run a fever around 100° to 102°F.

The flu can be stealthy as well: According to the CDC, most healthy adults may be able to infect others from one day prior to showing symptoms and for five days after that, with or without a fever. Some young children with weakened immune systems may be contagious for longer than a week.

Why it's not true: The flu and the common cold are caused by different viruses. So a cold can't really "morph" into the flu. If you or your child develops the flu, it was caused by a flu virus in the first place. Because the two types of illnesses have similar symptoms, it can be challenging to tell the difference between them based on how you feel. But, generally, the flu is worse than a cold, with more intense symptoms such as fever, body aches, extreme tiredness, and a dry cough. People with colds are more likely to have a runny or stuffy nose. Colds generally don't result in serious health problems, such as pneumonia, bacterial infections, or hospitalizations.

Special tests usually must be done within the first few days of illness to determine if a person has the flu. Last year Jennifer Higgins of Midlothian, Virginia, had her then 11-year-old daughter Lauren tested for H1N1; the diagnosis was positive. Higgins, after showing the same symptoms 12 hours later, deduced that she, too, had the virus. Although Higgins never was tested, her doctor agreed with her self-diagnosis.

Why it's not always true: Most people who get the flu will have a mild case and won't need medical care or antiviral drugs. They'll fully recover in less than two weeks. But make no mistake: The CDC warns that complications from the flu—whether it's H1N1, the seasonal flu, or another flu virus—can be deadly. An average of 36,000 people die each year from the flu and more than 200,000 are hospitalized. Pneumonia, bronchitis, sinus infections, and ear infections are examples of flu-related complications. The flu can also make chronic health problems worse. For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic congestive heart failure may find that the flu worsens this condition.

Those at higher risk for flu complications include children under 5, adults over 65, pregnant women, and those with chronic illnesses. Visit a doctor or the emergency room if you have any concerns about pneumonia or dehydration.

Why it's not always true: Staying away from sick people is one way to help avoid getting sick, but it's not foolproof. After all, people can be contagious without showing any symptoms (see Myth #4). Experts point to the flu vaccine as the best preventive measure against the flu. The Advisory Committee on Immunization Practices (ACIP), which advises the CDC on vaccine issues, recommends that all people age 6 months and older receive an annual flu vaccination.

But until you or your child can get vaccinated—or if you choose not to—washing hands regularly will help avoid both a cold and the flu.

And yes, avoid direct contact with visibly sick people whenever possible. When you're sick yourself, do others the courtesy of staying home. "We've really worked on teaching our kids to keep a respectful distance from others if they're sick when we do have to go out, especially if we're getting together with their grandparents," says Swiatek.

Why it's not true: Although you immediately become immune to the one particular flu virus you contracted, after that flu runs its course you could still contract a different flu virus, a cold virus, or a virus that causes pneumonia, according to Dr. Coffin. Higgins knows this first-hand. After she and her daughter battled H1N1, they both wound up with what Higgins describes as a "lovely parting gift" of double pneumonia (when the pneumonia is in both lungs). The 2010-2011 flu vaccine protects against an influenza A H3N2 virus, an influenza B virus, and the 2009 H1N1 virus that caused so much illness that year. These are the three viruses that research suggests are most common this flu season, according to the CDC.

Why it's not always true: The nasal mist flu vaccine is approved by the FDA for use in healthy people 2 to 49 years old who are not pregnant. Those who are not eligible for the LAIV vaccine include:

• People at high risk for complications from influenza, including those with chronic heart or lung disease, such as asthma or reactive airways disease; people with medical conditions such as diabetes or kidney failure; or people with illnesses that weaken the immune system, or who take medications that can weaken the immune system.

• Children younger than 5 years old with a history of recurrent wheezing

• Children or adolescents receiving aspirin

• Pregnant women

• People who have a severe allergy to chicken eggs or who are allergic to any of the nasal spray vaccine components

Bottom line: Consult with your doctor about your medical history before the two of you decide which vaccine is best for you.

Why it's not true: "At the risk of sounding trite," says Dr. Coffin, "it's never too late; or, it's too late only on the date the very last flu virus hits for the very last time." Flu season often peaks in February but can extend all the way into the month of May. Because no one can accurately predict when the very last flu virus will hit for the last time, as long as the vaccine is available, it's not too late to get it. Your state or local health department has a list of locations in your area where the vaccine is still available.

Why it's not true: Flu viruses do change from year to year, which means two things: First, you can get the flu more than once during your lifetime. The immunity (natural protection that develops against a disease after a person has had that disease) that is built up from having the flu caused by one virus strain doesn't always provide protection when a new strain is circulating. Second, a vaccine against flu viruses circulating last year may not protect against the newer viruses. That's why the flu vaccine is updated to include current viruses every year. Another reason to get flu vaccine every year is that after you get vaccinated your immunity declines over time, Dr. Coffin explains. Your immunity may be too low to provide protection after a year.

Why it's not true: Flu antiviral drugs work only against flu viruses. They won't help reduce symptoms from the common cold or any other flu-like illnesses caused by viruses other than flu viruses. And if you have "leftover" prescription flu medication that you're thinking of passing along to another family member who seems to have the flu? "No, no! Please, no!" says Dr. Coffin. "It is never OK to share your prescription medication with someone else. Besides, it won't work." Only your doctor can test you to determine if you actually have the flu and then determine whether influenza medication will help you.