The fall flu-shot clinics have popped up everywhere in the community. Normally the flu doesn’t peak until February, but vaccination against the flu virus should begin around mid-October.
Flu vaccines have been used in the U.S. since the 1940s. The shot is made from inactivated influenza virus. The vaccine is injected into the skin and the body’s immune system makes antibodies to the virus. Then, if we get exposed to the live virus during flu season, we already have defenses to fight it off.
Each year the flu vaccine is modified to protect against those viruses that are most likely to be seen during this year’s flu season. Influenza A and B are the types that cause the epidemics. The vaccine includes subtypes of both A and B to provide a range of protection.
The viruses can slowly change (mutate) over time. Antibodies your immune system made to the virus last year, either by receiving the vaccine or by getting the flu, may not recognize this year’s flu virus. This is why the vaccine is offered yearly, to protect against both common and new strains. These small differences in the virus also mean you could get the flu more than once during the winter season.
There is no shortage of the vaccine this year. This was a major problem a few years back. The vaccine is generally available to all, but those at highest risk for severe complications of influenza should receive the vaccine annually. This includes people with asthma, heart disease, diabetes or chronic lung disease; individuals older than age 65; children between six and 23 months of age; and people who live with or care for someone at high risk.
In 2005, sporadic cases of the flu began to be seen in this area in December and peaked in early February. Last year, cases of the flu started sporadically in early November. The season peaked in mid-February.
Influenza is a respiratory illness. The virus is highly contagious. It is generally transmitted from person to person through respiratory droplets, from coughing or sneezing. An infected individual can begin spreading the virus one day before developing any symptoms, up to seven days after the onset of symptoms.
Each year about 200,000 people are hospitalized and nearly 30,000 die due to complications of influenza. Those most at risk are the very young and old. Children less than 4 years of age are hospitalized most, due to wheezing, croup, dehydration and pneumonia. Those 65 and older can also develop severe pneumonia, as well as worsening of chronic health conditions such as heart failure, emphysema/asthma or diabetes.
The current flu shot is safe, using a killed virus, so there is no way to get the flu from the vaccine. Local reactions such as redness, tenderness or pain at the injection site can occur. Muscle aches and a low-grade fever may be seen. Because the vaccine is made in eggs, people allergic to eggs should not receive the vaccine.
A nasal spray vaccine is also available. It is made with a live, weakened virus and is approved for use only in healthy individuals ages five to 49 years. Generally it takes two weeks for either vaccine to become effective in your body.
The content in this column is for informational purposes only. Consult your physician for appropriate individual treatment. Dr. Reynolds practices Family Medicine in Chesterfield.