What is influenza?
Influenza is a viral infection that sickens millions of people each year and can cause serious complications, especially in children and older adults. The symptoms of influenza (flu) appear suddenly and often include: fever, body aches and pain, headaches, fatigue, dry cough, runny nose, sore throat, and loss of appetite. Influenza usually does not cause symptoms in the stomach or intestines, such as vomiting and diarrhea.
The virus is spread from person to person through: direct contact such as shaking hands, small droplets that form when a person sneezes or coughs, and contact with objects such as handkerchiefs that have been in contact with fluids from an infected person's nose or throat. People who have the flu are most likely to pass it to someone else from 1 day before to 5 days after symptoms develop. Symptoms usually develop 1 to 4 days after you are infected. Because symptoms may not develop for a couple of days, you may pass the flu to someone before you know you have it.
The risk of developing severe symptoms and complications is higher for: children younger than 4 years of age, adults age 65 and older (about 90% of the deaths caused by flu occur in this age group,) women who will be in their second or third trimester of pregnancy during the flu season, people who have chronic obstructive pulmonary disease (COPD), other lung diseases, or heart failure, people who have a medical condition (such as acquired immunodeficiency syndrome [AIDS]) or who are using a medication that impairs the immune system.
How can influenza be prevented?
You can help prevent influenza by getting immunized with an influenza vaccine each year, ideally in late September, October or November. The inactivated influenza vaccine commonly known as the "flu shot," is given by injection. This form of the vaccine effectively prevents most cases of the flu, although success rates vary according to age, health status, and how closely the virus strains contained in the vaccine match those that are circulating through the population.
Even if a flu shot does not prevent the flu, the vaccine can reduce the severity of flu symptoms and decrease the risk of complications. Studies have found that the flu shot results in fewer days missed from work and fewer visits to a doctor for respiratory infections, and it reduces the number of people who develop complications from the flu, such as pneumonia and dehydration.
The benefits of getting a flu shot far outweigh the risk of flu shot side effects. The most common side effects can include: soreness and/or swelling in your arm where the vaccine was administered, cold-like symptoms, including sniffles, headache, runny nose, sore throat, cough, and body aches for a day or two after getting the flu shot. In some cases, patients may also experience a low-grade fever.
Who should not get the flu shot?
According to the CDC, you should not get a flu shot or influenza vaccine if you have had an allergic reaction to a flu shot in the past, you have an allergy to eggs, or if you have previously developed Guillain-Barre syndrome within 6 weeks of getting a flu shot.
