Influenza (the Flu) is a respiratory illness caused by influenza viruses A or B and spread by respiratory secretions of infected individuals. Symptoms of the flu include fever, cough, sore throat, runny nose, muscle aches, headaches, fatigue, vomiting and diarrhea (more common in children than adults). The flu can range from a mild to severe illness, leading to hospitalization and even death. On average more than 200,000 people in the United States are hospitalized each year due to respiratory and heart illnesses associated with the influenza virus.
Those at highest risk for complications related to the flu include children less than 5 years old, adults over 65 years old, pregnant women, residents of long term care facilities including nursing homes, and those with chronic medical conditions. Some of these conditions include chronic lung disease such as asthma and COPD, heart disease (heart failure, coronary artery disease and congenital heart disease), sickle cell disease, diabetes, kidney and liver disease, HIV and cancer.
Who should get the flu vaccine?
Everyone 6 months old and older should receive the flu vaccine yearly. Children younger than 6 months are too young to receive the vaccine but are at a high risk of complications related to the flu. The guidelines now recommend even those with an egg allergy of any severity should receive the flu vaccine, though it should be given in a medical setting. Getting vaccinated yourself can help protect those around you, including children, the elderly, and those with chronic health conditions that put them more at risk. It is also important to realize the virus can spread before you even experience any symptoms. The virus can infect others one day before symptoms develop and up to a week after becoming ill.
It is best to receive the vaccine between September and November but can be given as late as February. Outbreaks usually start around October but usually peak around January and February. The flu vaccine can also be given at the same time as the pneumonia vaccine but should be given in different locations.
Can the flu vaccine give you the flu?
No, this is a common misconception. The flu vaccine is made from inactivated (dead) virus or with no virus at all (recombinant vaccine), which means it cannot cause the flu. You can experience side effects from the vaccine, including soreness or redness at the injection site, low grade fever, aches, or an allergic reaction. These symptoms are all mild and short lived. The only exception is nasal spray flu vaccine (Flumist) which is made from weakened live virus.
What vaccines are available this year?
There are trivalent vaccines (three components) and quadrivalent vaccines (four components). The trivalent vaccines protect against 2 influenza A viruses (H1N1 and H3N2) and 1 influenza B virus. The quadrivalent vaccines contain protection from the same viruses in the trivalent vaccines as well as an extra influenza B virus. There is also a high dose version of the trivalent vaccine available for adults over 65 years old. The nasal spray, a live attenuated vaccine (Flumist), is only indicated for those between the ages of 2-49 years old and cannot be used in those who are pregnant or have certain medical conditions. Speak to your provider to see which vaccine is best for you.
Why do I need to get flu vaccine every year?
The flu virus mutates and changes each year. Every year the CDC and the World Health Organization researchers track the virus activity, and try to determine which isolates of the influenza viruses will be most common this season. The vaccine is made based on this information.
Immunity to the virus also declines over time, lasting about 8 months. A vaccine every year is needed to provide optimal coverage.
Can you still get the flu after receiving the flu vaccine?
As mentioned before, the vaccine is made to protect against the flu virus that research indicates will likely be the most common this season, but this is done months before flu season occurs to ensure production of the vaccine in time. The flu virus can also change and mutate during the current flu season. There is a risk that the vaccine will not be the best match for the current circulating virus, but the antibodies made in response from vaccination can still provide some protection against these related viruses. This may prevent an infection from being more serious than with no coverage from the vaccine at all.
After receiving the vaccine it takes about 2 weeks for your body to produce antibodies to protect you from the virus. You can still become infected with the flu if you are exposed to the virus during this 2 week period.
The only way to protect yourself from the flu is by getting vaccinated every year. It is also important to prevent germ spread by washing your hands and covering your mouth when coughing or sneezing. If you develop symptoms of the flu, you should immediately contact your doctor within 48 hours of symptom onset. If given a prescription for antiviral medication, start the prescription immediately.