Infectious disease experts explain how to stay healthy during the flu season

About 40 million people contracted the flu last year, with hundreds of thousands hospitalized and 35,400 to 61,000 deaths, including 134 children, according to the Centers for Disease Control and Prevention.

The CDC recommends that people aged 6 months or older receive flu vaccinations by late October, at the beginning of the season before the virus starts spreading, but getting a vaccination later can still be beneficial.

Infectious disease experts David Cennimo at Rutgers New Jersey Medical School and Tanaya Bhowmick at Rutgers Robert Wood Johnson Medical School discuss this year's flu season, the effectiveness of the vaccine and how you can protect yourself.

What daily precautions can people take to prevent infection?

Cennimo: Influenza is spread through droplets, such as a sneeze or cough, as well as through contact with surfaces contaminated by the virus. The CDC recommends preventive precautions to stop the spread of germs, such as avoiding contact with sick people, staying home for at least 24 hours after your fever breaks, covering your nose and mouth when sneezing or coughing, washing your hands with soap and water after using a tissue and avoiding touching your eyes, nose and mouth. People also should avoid congregating in public settings when they are ill to minimize the risk of infecting others.

What complications can accompany the flu?

Cennimo: Common symptoms include fever, chills, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, vomiting and diarrhea. The last two are more common in children than adults. A doctor can prescribe medication to treat the flu. It is most effective if started within the first 48 hours of symptoms, so it's important to call as soon as flu is suspected.

Sinus and ear infections are examples of moderate complications of flu, but pneumonia is a frequent serious complication, particularly in people with chronic lung disease. Other serious complications include inflammation of the heart, brain or muscle tissues and multi-organ failure, such as respiratory and kidney failure. The flu itself can lead to respiratory failure and death.

People who are over 65 have a higher risk of complications and a higher mortality rate. The CDC estimates that 70 percent to 90 percent of annual flu deaths are in people over 65. People with other chronic conditions also fare worse when they have the flu. For example, people with coronary artery disease have an increased risk of heart attack if they contract influenza.

Why is it important to be vaccinated?

Bhowmick: Besides protecting you from common strains of the flu, the vaccine will lessen the severity of symptoms if you contract a strain that was not included. Also, some people can be infected with the flu virus but have no symptoms. During this time, those people may still spread the virus to others, especially vulnerable populations like the elderly, children and those who have an impaired immune system, such as cancer patients undergoing chemotherapy and people with HIV or pulmonary disease. Having the vaccination will stop the virus from infecting others.

What strains will the vaccine cover this year?

Cennimo: As in previous years, the flu vaccine will cover both Influenza A and B types. Last year's Influenza A strain was updated to better match circulating viruses, but the Influenza B vaccine remains the same as last year.

A majority of last year's cases had an H1N1 component, against which the vaccine was 45 percent effective. The changes in this year's Influenza A vaccine were made due to a late emergence of an H3N2 strain that the vaccine did not cover. Fortunately, there were not many people infected.

Is the nasal mist vaccine as effective as an injection?

Bhowmick: FluMist, which can be given to people ages 2 to 49, contains a live virus and is effective if administered properly. Some studies have suggested the nasal spray mist was not as effective for previous seasons, but the nasal vaccine has been reformulated and it's believed to be just as effective as the injection.

How long is the vaccination effective?

Cennimo: The flu season ranges from October to as late as May, with peak activity between December and February. The CDC recommendation of having the vaccine by late October is appropriate. Vaccine efficacy is approximately six months. So, if you receive your flu shot in September and the flu season runs later, you are not as well protected during those months. But if you delay receiving the vaccine, there's a chance you might not get around to it.

Can you get the flu from the flu vaccine?

Bhowmick: No, but people should realize the vaccine takes two weeks to be effective, so they still could contract the flu during this period. The vaccine exposes your body to a weakened form of the virus, which allows you to mount an immune response. ​So, essentially you are getting a "mini-flu" illness, which is why people may feel ill after getting the vaccine.