5 Flu Vaccine Myths


5 Common Myths About the Flu Vaccine

The flu season predictably comes and goes each year and still people choose to ignore its perils by not getting the annual flu shot. This is unfortunate, experts agree, because influenza can strike even the healthiest among us and, at the very least, give those afflicted a miserable ride before they begin to recover.

Why people avoid the annual flu shot is complicated, but at least some of the avoidance has to do with misconceptions about influenza and the vaccines that are designed to prevent it. Here are five common myths about influenza and its protective vaccines that Lisa Grohskopf, MD, MPH, medical officer in the Influenza Division at the Centers for Disease Control and Prevention (CDC), and Paul Offit, MD, professor of pediatrics and director of the Vaccine Education Center at Children’s Hospital of Philadelphia, hope to dispel.

Myth 1: The Flu Vaccine Can Cause the Flu

The flu vaccine itself absolutely, categorically, cannot cause the flu. As Grohskopf explains, most of the influenza vaccines in use today contain either killed viruses, weakened viruses, or no virus whatsoever, so a person cannot get the flu from any vaccine. Take the nasal spray vaccine, for example. This vaccine actually does contain a live, albeit attenuated (weakened) virus, but these viruses can only replicate at cooler temperatures within the nose and cannot infect the lungs or other parts of the body where temperatures are warmer; even this vaccine can’t cause the flu.

So, what might be happening if someone has a flu shot and comes down with the ‘flu’?
Several things might explain ‘flu’ symptoms. First, it takes about 2 weeks for the body to mount an immune response to any influenza vaccine, during which time people will not be protected against influenza infection, no matter how good the vaccine is. Most people get their flu shot in a clinic or doctor’s office where sick people congregate, some of whom are probably there because they have the flu! A host of other upper respiratory tract viruses have the same seasonal pattern as influenza, and these can cause mild, influenza-like symptoms which people attribute to the flu but which are caused by an unrelated virus. People may also experience flu-like symptoms despite getting vaccinated if they’ve been exposed to a virus in the community that differs from those in the seasonal vaccine, so they won’t be protected against it. The majority of side effects will be related to where the vaccine was given—a sore arm or swelling.

Evidence also suggests that if you are vaccinated against influenza and still get the flu, the illness will be less severe than it would have been had you not received the vaccine. In one CDC study, for example, patients hospitalized with the flu who had not been vaccinated before hospitalization were two to five times more likely to die than hospitalized patients who had previously been vaccinated.

Myth 2: Healthy People Don’t Need a Flu Shot

You may hear someone say, ‘I’m healthy, I never get the flu, so I don’t need the annual flu shot’. Some people are more vulnerable to getting severely ill with the flu than others—those with chronic lung or heart disease or those whose immune systems are compromised in some way. On the other hand, not even the experts can predict, on an individual basis, who among us is going to get the most severely ill from the flu. Sometimes, perfectly healthy adults and even children, who have no risk factors for severe illness, get sick enough from the flu to require hospitalization or even die from the flu.

Given that who will be most severely affected cannot be identified ahead of time, “the recommendation is for all people from the age of 6 months and older to get the annual flu shot” Grohskopf says. Furthermore, especially for adults who may be caring for very young infants, pediatricians warn that infants who are still too young to be vaccinated cannot make protective antibodies against influenza until they are approximately 6 months of age. These young infants are especially vulnerable to getting the flu from their caregivers and anyone around them who harbors the infection. In a CDC study, the flu shot reduced the risk for influenza-related death by 51% among children with high-risk medical conditions and by 65% among healthy children.

According to Offit, “If you don’t get the flu shot for yourself, get it to protect the most vulnerable people around you who may be at greater risk of getting the flu and suffering from its potentially fatal consequences.”

Myth 3: The Flu Is Just a Bad Cold

Have you ever heard someone say, “It’s just the flu, no big deal; the flu is just like a bad cold.” Offit emphasizes that, “Theres no such thing as just the flu—people really need to know what the flu is. Flu, knocks you on your butt.” People can often identify the hour the infection started. Influenza starts with symptoms of high fever, shaking, chills, achy muscles, and headache. In the worst-case scenario, people can develop severe lower respiratory tract symptoms such as a racking cough and even pneumonia. In contrast, with a cold you might have a scratchy throat, runny nose, or a mild fever. However, people are rarely, if ever, hospitalized for a cold. Contrast that with what the flu did to people last year. During the 2017-2018 influenza season, CDC estimated that 48.8 million people got sick with the flu, 22.7 million people sought some form of medical attention because of flu-like symptoms, 959,000 were hospitalized because of the flu, and 79,400 people died. 

Myth 4: The Flu Vaccine Isn’t Effective

Some people believe that none of the vaccines are all that effective against the flu, especially in older adults, so why should they bother? At their best, standard-dose influenza vaccines afford the best protection against illness in children under the age of 8 years, in whom they are about 65% protective against the flu. After that, vaccine efficacy depends both on the patient’s age and how well the viruses in the vaccine match those circulating in the community. Both Grohskopf and Offit confirm that the vaccine is a good match for this year’s circulating viruses, especially the H1N1 strain, which is the predominant strain this year.

Vaccination against the flu doesn’t only protect people from influenza illness. According to a meta- analysis of major clinical trials, adult vaccination against the flu cuts the risk of having a major cardiovascular event by more than one third, an effect that is especially pronounced among patients with active coronary disease.

Myth 5: It’s Too Late to Get a Flu Shot

Heres a common refrain as the winter progresses and spring seems to be just around the corner: “The flu season is well underway, so its too late to get the flu shot.” It’s true that CDC recommends people be vaccinated in time to be protected against flu outbreaks, typically by the end of October, although flu outbreaks can happen weeks earlier, as they did this season.  However, as long as flu viruses remain in circulation, it’s not too late to get vaccinated—even in January and February, when the flu season is likely peaking. As CDC points out, flu activity can last as late as May, allowing plenty of time to get sick from the flu and plenty of time to prevent it. As long as flu is circulating in our community, it is reasonable to get vaccinated. The important thing is to just get vaccinated!

Beth Ewing, RN, MSN, CNM, WHNP-BC Parish Nurse

1. www.medscape.com 18 Jan 19
2. Udell J, Zawi R, Bhatt D, et al. Association between influenza vaccination and cardiovascular outcomes in high-risk patients: a meta-analysis. JAMA. 2013;310:1711-1720. Abstract

Beth Ewing