HOUSTON (December 29, 2014)

According to the CDC, this year’s flu vaccine may not be as effective because the current strain of the virus has mutated. Researchers are concerned this could translate to a flu season that is more severe than usual. Based on daily volumes for the month of December, the Memorial Hermann-Texas Medical Center (TMC) Campus is currently seeing the usual winter volume of flu patients, but that could change at any moment.

So what does this mean for those who already received the vaccine this year? And for those who haven’t yet, is it too late? Or would it even do any good? Arlo Weltge, MD, a UTHealth emergency medicine physician affiliated with Memorial Hermann-TMC, provides answers to all these questions and more.

What causes the flu?

Influenza is caused by a group of viruses that live in respiratory secretions of affected individuals.

What are the symptoms of the flu?

Influenza normally starts with an achy body and progresses to fever with chills, coughs and headaches. Influenza can range from mild to severe, depending on immunization to the virus, allowing some people to return to work and/or school in just a few days.

Is the flu harmful?

According to the CDC, over 50,000 people died of influenza and pneumonia in the United States in 2010. The influenza virus can range from mild to severe depending on the health of the person who is infected and his or her body’s immunization to the virus.

Does the flu shot really work?

The influenza vaccine does work, but it is not a cure. The vaccine is created to immunize the body from three to four strains depending on the vaccine received. The strains that people are vaccinated with are strains that the CDC and other organizations predetermine to be the dominant influenza strains of the season. The vaccination prepares the body and starts the body’s immunization to these strains. The vaccine may not keep people from getting the virus but it lessens the severity of the virus and decreases influenza-related hospitalizations by approximately 70 percent.

Is it true that the flu vaccine is less effective this year? And, if so, should I still get it and why?

According to the CDC, one of the influenza strains mutated making the vaccine against that strain less effective. However, vaccination can still provide some protection against drifted, or mutated, viruses and might reduce the likelihood of severe outcomes such as hospitalization and death; for example, if one contracts the mutated strain but has received the immunization, one may only be on bed rest for three days instead of a full week or more. In addition, the vaccine is still effective for the other strains it covers that have not mutated, such as influenza A (H1N1) and B viruses. Receiving the vaccine will also reduce one’s risk of passing the flu on to others.

Is the nasal spray option as effective as the flu shot?

The nasal spray vaccine, called FluMist, is a needle-free version that is sprayed up the nose. It is a more effective vaccine in children. It’s made the old-fashioned way, using eggs, so those with egg allergies will want to receive the shot instead. The CDC also says because it’s a “live” vaccine, it may protect against the mutated strain better than other vaccines.

If I’ve had the flu before, can I get it again?

There are many strains of influenza, meaning that people who have had the flu before may get it again. Their bodies have developed an immune system for one strain but not all of them. This is another reason to get vaccinated against influenza annually. Each year, different strains are vaccinated and over the years these immunizations build up and protect people better from the influenza viruses.

What strains of flu does the vaccine protect against?

This year’s vaccine was targeted to protect against H3N2 strain, which is the one that has mutated, and either one or two B strains, depending on the vaccine, and the H1N1 strain.

Can pregnant women get the flu shot?

Yes, pregnant women should receive the influenza vaccine to protect themselves and the baby too. Pregnant women have a higher risk for serious complications from influenza.

At what age do you need to get a flu shot?

The CDC recommends anyone above the age of 6 months gets the influenza vaccination.

What are the most common side effects from the flu shot?

The most common side effects are bruising and pain at the injection site. Serious side effects can include difficulty breathing, diffuse rash and paralysis but these side effects are rare. People have a greater chance of being hospitalized from the flu.

When do I need to get the vaccine?

Flu season is from October 1 to April 30. It is recommended to get the vaccine in September or early October. If you have not gotten the vaccine yet, it’s not too late to get one now but, generally speaking, it’s always better getting it as early as possible.

Does the flu shot contain thimerosal?

Thimerosal is a preservative which keeps bacteria and other germs from contaminating the vaccine during its storage. The influenza shot does contain thimerosal but the nasal spray does not.

Aren’t vaccines dangerous? I hear they can cause developmental disorders such as autism.

Studies show there is no link between receiving a vaccine and autism. Vaccines have led to more diseases like measles, meningitis and mumps becoming rare occurrence in the United States – diseases that affected millions before.