Patient Handout: Flu Season


What to Expect – Flu Season 2018-2019

Influenza – or ‘the flu’ – can occur year-round. However, the flu is most prevalent during the fall and winter months. When ‘flu season’ strikes varies on a yearly basis, but flu activity begins to heighten in October, peaking between December and February, and tapers by May.

According to the Centers for Disease Control (CDC), February has been the virulent month since the 1982-1983 flu season.

The 2017-2018 flu season was high in severity. The CDC began using a new methodology to classify severity of flu seasons. According to the CDC, “The 2017-18 season was the first season to be classified as a high severity across all age groups.” Influenza A (H3N2) was the most dominant flu virus, although influenza B was more commonly reported during the month of March 2018.

The 2018-2019 is difficult to predict. There are several variables:

  • The match between the vaccine viruses selected
  • Circulating viruses that season
  • Although scientists attempt to predict which viruses will be most virulent, it is impossible to predict which viruses will be most dominant

Emerging Strains

Flu viruses are constantly changing. As such, scientists who create flu vaccines must attempt to predict which strains will be most prevalent, selecting the top three to four.

This year, the trivalent (three-component) vaccines contain:

  • A/Michigan/45/2015 (H1N1)pdm09-like virus
  • A/Singapore/INFIMH-16-0019/2016 A(H3N2)-like virus (updated)
  • B/Colorado/06/2017-like (Victoria lineage) virus (updated)

Quadrivalent (four-component) vaccines contain:

  • All of the above, plus:
  • B/Phuket/3073/2013-like (Yamagata lineage) virus

Flu Prevention
Here are several tips to prevent the flu from occurring:

  • Avoid contact with people who are ill. If you are ill, stay home. Confine yourself to your bedroom to protect your loved ones. If your loved ones are ill, do your best to avoid contact.
  • Cover your mouth and nose. The flu is spread by coughing, sneezing, and unclean hands.
  • Wash your hands. Use soap and water to keep hands clean, especially after coughing and sneezing. When soap and water are not available, use hand sanitizer.
  • Abstain from touching your nose and eyes. Germs can be spread from these orifices.
  • Keep your home clean. Disinfect surfaces often.
  • Prevent illness by getting rest, staying active, eating well, and staying hydrated.
  • Get a flu shot.

Shot… or no Shot?

The CDC reported that, “The overall vaccine effectiveness (VE) of the 2017-2018 flu vaccine against both influenza A and B viruses is estimated to be 40 percent. This means the flu vaccine reduced a person’s overall risk of having to seek medical care at a doctor’s office for flu illness by 40 percent.”

Experts agree that the 2017-2018 vaccine was not a “good match” – but that doesn’t mean that the vaccine was completely ineffective! According to the CDC, “A less-than-ideal match may result in reduced vaccine effectiveness against the flu virus that is different from what is in the flu vaccine, but it might still provide some protection against flu illness.”

It is entirely possible to get the flu while getting the vaccine – even in a year with a “good match.” Why? As we’ve discussed, flu vaccines fight certain strains of the flu that are expected to be particularly virulent. In addition, a flu vaccine can take a couple weeks to really start “working” – this means that encountering the flu (even one of the strains in the flu vaccine) can cause illness.

There are very few people who shouldn’t get the flu shot. Those who are contraindicated include:

  • Babies less than 6 months old
  • Those with a history of Guillain-Barre syndrome within the past six months
  • Those with a life-threatening allergy to a component of the flu shot

Those with egg allergies likely can get a flu shot. Flu shots contain a low amount of egg protein – and there are flu shots without egg protein.


Centers for Disease Control and Prevention. (2018, July 12). The flu season. Retrieved from

Centers for Disease Control and Prevention. (2018, August 30). Frequently asked flu questions 2018-2019 influenza season. Retrieved from

Centers for Disease Control and Prevention. (2018, July 20). Preventing the flu: good health habits can help stop germs. Retrieved from

Centers for Disease Control and Prevention. (2018, October 11). Summary of the 2017-2018 influenza season. Retrieved from

WebMD. (2017, September 11). Who shouldn’t get the flu shot? Retrieved from


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About Author

Krystina Ostermeyer RN, BSN, CDE
Krystina Ostermeyer RN, BSN, CDE

Krystina is a 30-something RN, BSN, CDE who has worked in a variety of nursing disciplines, from telemetry to allergy/immunotherapy to most recently, diabetes education. She is also a writer and has enjoyed expanding her writing career over the past several years. She balances her careers as a nurse and a writer with being a wife and a mother. She has a four year old son who is an inquisitive, energetic little guy who is up for anything. She also enjoys reading, traveling, cooking, baking, and yoga (both practicing and teaching).

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