Flu Facts You Should Know

with Dr. Wael Haidar, Adena Infectious Disease Specialist

What is 'the flu?'

The flu is a virus composed of two different influenza viruses, Influenza A and Influenza B. Influenza A is further separated into multiple different variants including avian flu (H7N9), swine flu (H3N2) and H1N2. The flu has proteins on its surface that change frequently and mutate into new strains. That happens frequently in Influenza A and less frequently in Influenza B, hence the different types of flu that appear every year.

What are the symptoms?

Symptoms of flu vary significantly from one patient to the other. Most likely, symptoms include upper respiratory infection including runny nose, sinus pressure, sore throat and generalized aches and pains with fatigue and sometimes low-grade fever. Other cases can vary widely, from meningitis (infection of the brain lining) to pneumonia and even gastroenteritis or diarrhea.

How is the flu spread?

The flu gets spread from one person to the other through respiratory secretions of infected persons. In other words, coughing and sneezing will transmit the flu virus to the environment. Droplets are typically airborne for about three to six feet. Beyond that the virus is too heavy and falls to the ground. The flu can live outside the body for several hours on hard surfaces, which essentially means that if somebody coughs or sneezes the flu virus droplets on a hard surface and few hours later somebody else touches that surface, they would be prone to contracting the virus.

When are you contagious?

Usually the person is contagious when they are still shedding the virus through their respiratory secretions. We likely shed the virus for about 24 to 48 hours before we feel ill, and this shedding continues for about three days while we feel ill. Studies show that the average duration of shedding of the virus is about five days. During that time the person is contagious.

Who should be immunized?

Immunization is recommended for every person older than six months. There are very specific circumstances where immunization is not recommended and sometimes it is actually contraindicated. Previously, patients with severe egg allergies could not receive the flu vaccine due to a component in the way we grow the virus. But most newly developed vaccines are well-tolerated, even in patients with egg allergies.

Can you get the flu from a vaccination?

No. The vaccine by itself is a modified and dead virus. That means the virus cannot replicate and spread in your body and give you the actual infection. Keep in mind that how the vaccine works is by stimulating your immune system to recognize the flu virus and be ready to fight it. So that immune response sometimes can make us feel tired, weak, achy and even a little sick.

Sometimes patients also confuse the flu with the common cold. Patients get the flu vaccine and get the common cold during the same season, thinking “the vaccine didn’t help,” which is not true since it was a totally different virus that gave them the common cold.

Who is at high risk or low risk for the flu?

The flu can affect everybody and anybody. Those more prone to severe infections are very young children with weak immune systems, older patients who are more prone to infections, and patients who have an immunosuppressant status. Immunosuppressed patients include patients who are taking immunosuppressive therapy for illnesses like rheumatoid arthritis or inflammatory bowel disease or lupus. Patients who are HIV positive are also more vulnerable to severe infections.

Why does flu seem to be a bigger problem in the winter?

Influenza A is usually more seasonal then Influenza B. The virus thrives during cold and dry weather. What we have seen is that during hot and humid weather, the virus is less affecting and does not get transmitted easily. Keep in mind that in the winter season, kids are back to school and they have more contact with each other in closer surroundings, making them even more prone.

What are the best ways to treat the flu?

The best way is not to treat the flu. The best way is to prevent the flu. Over 200,000 people are admitted to hospitals in the U.S. every year because of the flu virus. Prevention can save lives and can save hospital admissions. Preventing the flu can save the health care industry billions of dollars per year. That is not including wages lost due to time off of work when someone is sick. But even under the best circumstances, people still get infected with the flu virus, and we have ways to treat it. Usually, we reserve treatment to patients with severe complications, or patients at high risk for complications. We have multiple medications to choose from, but the most commonly used one is oseltamivir (Tamiflu). This medication is most effective when given early during the onset of symptoms, preferably within the first 48 hours.

If you have never had a flu shot should you get one?

Yes. Everybody should get the flu vaccine even if they have never had it before. There is something called herd immunity. If everybody receives the flu vaccine the whole society, the whole community and the whole population become more immune. I strongly recommend for everyone to get the flu shot.