Mother checking daughter's forehead temperature

Important Facts About This Season’s Flu Shot

October is here, which means flu season is just around the corner and here to stay for at least the next six months. That said, unless you’re one of a very small group of people that shouldn’t get the flu shot, it’s time to toughen up and get your annual influenza vaccination.

According to the Centers for Disease Control and Prevention, almost everyone aged 6 months and older should be vaccinated by the end of October. Since it takes around two weeks for antibodies to develop and provide maximum flu protection, there’s no time like the present.

“Most of the time, the peak of the flu season is in February however it can be earlier or later, even in March,” says Karna Gocke, M.D., family medicine physician at Texas Health Family Care – Prosper, a Texas Health Physicians Group practice. “Generally, we recommend that patients get shots in the second half of September and in October since it can take up to two weeks for the shot to be fully effective.”

While most people experience mild to severe illness due to the flu, others, such as young children, pregnant women, the elderly and those with medical issues, are at higher risk of hospitalization or death due to flu complications.

Viruses that cause the flu constantly change, meaning new vaccines are produced every year to provide the best protection for the most people. Researchers determine which three or four viruses will be the most common for the upcoming year and develop vaccines accordingly.

For the 2017-2018 flu season, three-component vaccines will contain the following:

  • A/Michigan/45/2015 (H1N1) pdm09-like virus
  • A/Hong Kong/4801/2014 (H3N2)-like virus
  • B/Brisbane/60/2008-like (B/Victoria lineage) virus

Four-component vaccines will also contain the B/Phuket/3073/2013-like (B/Yamagata lineage) virus.

For those who prefer the FluMist over shots, there’s bad news. The CDC’s Advisory Committee on Immunization Practices is recommending against live, attenuated influenza vaccines again this season, just like during the 2016-2017 flu season, due to their reduced effectiveness.

“Last year the flu vaccine was 48 percent effective, according to the CDC,” Gocke says. “They use trends from Asia and other countries to try and predict which strains will affect us, but each year is a gamble. The vaccine ranges generally from 30 to 65 percent effective, however even if you get the flu after being vaccinated, the vaccine seems to shorten the course of the illness. We will not know this season’s efficacy until after people have already gotten vaccinated, unfortunately.”

And if you think you can skip a year because you were vaccinated last year, Gocke says to think again, even if other family members have already been vaccinated.

“The flu vaccine has a limited time where it is efficacious. This means that it only lasts a few months, therefore, it must be given each and every flu season,” she says. “We recommend that everyone be vaccinated because if any member of the family gets the flu, it tends to quickly spread to other members of the family.”

Other than the vaccine’s limited time of efficacy, it’s important to get a new influenza vaccine every year because viruses are always changing and adapting. Flu viruses change in two ways, known as antigenic drift and antigenic shift, necessitating new vaccines each year to fight the latest “versions” of the viruses. Antigenic drift means small changes occur over time as the virus replicates. The immune system of a person previously exposed to a similar virus will often recognize it and respond, called cross-protection. As these minor genetic changes accumulate, however, a person’s antibody against the virus may no longer be close enough to protect against it and they will get sick.

Antigenic shift occurs when a sudden, significant change in influenza A viruses leads to the development of a new flu subtype so distinctive from previous versions that people don’t have immunity to it. An example of this major shift was the H1N1 swine flu pandemic in 2009, which led to several hundred deaths worldwide.

Gocke says the best precaution to take besides vaccinating is to adopt a good handwashing routine, which means washing frequently and scrubbing your hands for at least 20 seconds. Remembering to wash all surfaces, including some commonly missed spots like under your fingernails or your wrists, and always wash your hands before and after preparing food and treating wounds, and after using the restroom, touching an animal, blowing your nose or shaking hands with others.

Even after taking all the necessary precautions, it is still possible to come down with influenza. Some common signs and symptoms of the flu include:

  • High fever (over 101˚) and chills
  • Muscle or body aches
  • Fatigue
  • Headache
  • Dry cough and/or sore throat
  • Runny or stuffy nose
  • Shortness of breath
  • Vomiting and/or diarrhea (more common in kids than adults)

The flu is spread most commonly by respiratory droplets created when sick people cough, sneeze or talk, which can then be breathed into the nose or land in the mouth of people close by. Infection may also be passed along when a person touches their mouth, eyes or nose after coming into contact with a surface that has the flu virus on it.

Infected people can pass on the flu to others before even feeling sick, up to one day before symptoms show up and five to seven days after coming down with the flu. Once a person is exposed to the flu, symptoms usually start developing between one and four days. Flu tests are available but sometimes result in false negative results, whereby a physician may go ahead and treat a patient for the flu based on symptoms.

Anyone can become infected with the flu, but serious complications are more likely to occur in young children, people 65 and older, women who are pregnant and those with chronic medical issues. Some of the most common complications include bacterial pneumonia, ear and sinus infections, dehydration, and an aggravation of chronic health problems such as congestive heart failure, asthma and diabetes.

Despite the risk of severe symptoms, more than 55 percent of American adults and more than 40 percent of American children do not receive the vaccine every year. This can be due to multiple reasons but Dr. Gocke debunks one big misconception about the vaccine that may keep people from receiving it:

“The vaccine cannot give you the flu,” she stresses. “It can have some side effects, like muscle aches, however there is no chance that the vaccine can give you the virus.”

If you suspect you have the flu, see your doctor as soon as possible to receive testing and an antiviral prescription, which can lessen symptoms, shorten sick-time by one to two days, and reduce the risk of serious complications.

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