As we approach cold and flu season, it’s important for everyone over the age of 6 months to receive the influenza vaccine. In my office, I continue to encounter patients who are reluctant to be vaccinated primarily because they are misinformed. Let’s take a closer look at the flu and why you should protect yourself.
When is flu season?
Flu season typically occurs from October through May but peaks in January and February, so now is the ideal time to get immunized. It’s not too late, however, to be vaccinated even when flu season is here.
Is the flu really that serious?
In healthy adults and children, influenza is a moderately severe illness, but in the sick, elderly or very young it can be life-threatening. Death rates from influenza vary from season to season and are hard to measure. When flu proves fatal, it often is because a patient weakened by flu has developed pneumonia, which is listed as the cause of death. Death estimates have ranged from 3,000 to 45,000 in a given year. There are more deaths in years when influenza A (H3N2) is present, and 90 percent of influenza-related deaths occur in people who are over the age of 65.
How can I tell if I have the flu?
Symptoms include high fever, muscle aches, dry cough, chills, sore throat and upper respiratory symptoms such as runny nose and congestion. The flu can be diagnosed by a rapid laboratory test within the first two or three days of symptoms.
What can I do if I get flulike symptoms?
Antiviral medications are available by prescription but they must be started within a day or two of the onset of symptoms to help decrease the length and severity of the illness. The antiviral therapy is most important for patients with confirmed influenza and those at high risk of developing complications: pregnant women, children under 2, adults 65 or older and people with asthma, COPD or other chronic conditions.
Why do I need to get a flu shot every year?
Every year scientists attempt to predict what the prominent viruses will be that season and they develop the vaccine to contain those killed (or weakened) viruses. The viruses typically are from the influenza A and B family. This year the trivalent influenza vaccine will protect against two strains of influenza A and one strain of influenza B. Even if scientists are not 100 percent accurate in predicting which viruses will be major players, the antibodies your system makes in reaction to the vaccine will likely offer some degree of protection, as most of the viruses are related. Studies have shown that even at times when the vaccine is not a perfect match to the circulating viruses, receiving the flu vaccine reduces your likelihood of being hospitalized for a flu-related complication by close to 75 percent. Vaccinating pregnant women reduces the chances that their infants (up to 6 months) will be hospitalized for influenza by 92 percent.
I got the flu shot but still got the flu.
I often hear patients tell me that they got the flu from their influenza vaccine. I tell them this is scientifically impossible because the injectable flu vaccine contains inactivated virus, rendering it incapable of causing illness. The nasal spray vaccine contains a weakened virus that can grow only in the tissue of the nose, where it is cool.
There are several possible explanations in the cases of patients who report feeling sick after being vaccinated:
1. The patient became infected with a cold virus that caused a similar illness but was not influenza.
2. The patient was exposed to influenza just before the immunization or in the first two weeks after the vaccination when immunity had not yet been developed, then contracted the flu.
3. The patient was infected with a strain of influenza not found in or related to those in the vaccine.
4. The patient had limited immunity from the vaccine and did indeed develop the flu despite being immunized. This is more likely to occur in people over 65. But even so, the vaccine is useful because the illness is milder than it would have been otherwise.
What are this risks and side effects of a flu vaccination?
The most common side effects are injection-site tenderness and swelling. Occasionally patients experience a low-grade fever in the 48 hours after the injection. The nasal vaccine can cause nasal congestion, runny nose, sore throat or cough in addition to a low-grade fever and body aches. Severe reactions to the vaccine are rare. The vaccine is produced in contact with egg proteins, but it has been shown to be safe for egg-allergic patients, with symptoms limited to the skin (hives, rashes). People who have had life-threatening reactions to eggs should see an allergist to discuss being immunized with a recombinant influenza vaccine that does not contain egg protein. People who have previously had a severe allergic reaction to the vaccine — difficulty breathing or swallowing, drop in blood pressure, etc. — and people who developed Guillain-Barre syndrome within six weeks after an influenza vaccine should not be immunized again.
Dr. Mona V. Mangat is a board-certified allergist and immunologist at Bay Area Allergy & Asthma in St. Petersburg. Find her at bayallergy.com. If you have a question for the doctor, email her at bayallergy@gmail.com. Your question may be answered in a future column.