3 Mammoth Flu Myths -- Busted!

We may be on the downswing, historically, based on the weekly flu statistics released by the Centers for Disease Control and Prevention, but the threat of an influenza outbreak is always on the mind of the CDC.

Compared to 2013 it appears as if we're in for a milder year with regard to overall flu severity, but we're also not completely out of the woods yet with pneumonia and influenza death rates still pacing above the epidemic threshold as you can see from the pneumonia and influenza mortality chart below.

Source: Centers for Disease Control and Prevention.

One good sign, though, is that positively identified cases of the flu are currently at a 15-week low, which we can partially attribute to better awareness of the disease as well as preventative measures taken by Americans to get a flu vaccination.

However, the flu itself has always been somewhat of an enigma for most Americans. Throughout the years a number of myths and misconceptions have persisted which may have potentially held back the number of people getting vaccinated on an annual basis. Today, in the spirit of Foolishly educating and amusing, we're going to more closely examine three of the largest myths surrounding the flu and dive into some of the key players in vaccine development.

First, let's examine the three mammoth flu myths.

Myth No. 1: A flu shot is going to give me the flu.
No misconception has stood larger, or for such a long length of time, as the notion that by getting a flu shot you will get the flu.

Source: William Brawley, Flickr.

The truth of the matter is that you have zero chance of catching the flu by getting a flu shot. With the exception of AstraZeneca's (AZN 0.49%) FDA-approved nasal spray FluMist, all flu shots are manufactured using inactive strains of the flu virus. These inactive strains allow your body's immune system to recognize the virus as foreign, which in turn allows your body to build up an immunity to the flu virus.

In the case of FluMist, which is a live attenuated intranasal vaccine, a considerably weaker version of the live flu virus is given to the patient. Similar to the inactive version of the virus it can cause common cold-like symptoms, including headache, muscle aches, and low-grade fever, but it is simply not possible to get the flu from any sort of flu vaccination.

Myth No. 2: I got my flu shot, so I'm now immune to the flu!
Unfortunately there's no such thing as immunity to the flu, but getting a flu vaccination certainly gives you an improved chance of either not getting the flu, or getting a significantly weaker form of the flu.

In 2012-2013, the CDC posted a mid-season update that demonstrated a vaccine effectiveness estimate of 56% when combining all age groups. It was 47% effective against influenza type A and 67% effective against influenza type B. Ultimately, the goal of a flu vaccination isn't to keep people from getting the flu necessarily; it's to reduce the severity of the flu they may catch so as to keep them out of the hospital.

What will really determine whether or not you get the flu are three factors. First, your age and health are important. If you're young you have a better chance of fighting off the illness than say the elderly or infants do. Second, the health of your local community is important. Regions where widespread flu outbreaks are occurring are obviously hot spots where your chances of contracting the flu are higher. Finally, it depends on the year-to-year makeup of the flu vaccine. Researchers don't know for certain which flu strains will dominate, so they make an educated guess each year, and we cross our fingers that they're correct. The good news is that researchers have been right a lot more than they've been wrong over the years.

Myth No. 3: Flu shots are only for the elderly and children.
You certainly might feel invincible, but severe cases of the flu can strike anyone, including young adults. This year has been especially rough on people between the ages of 18 and 64 with the CDC noting that 61% of reported influenza hospitalizations (through March 8) were found in this age range. Over the last five years, this figure has generally been much closer to 35%.

One major concern is that only a third of the 18 to 64 year-old crowd gets vaccinated , exposing this age group to a considerably higher chance of getting a severe form of the flu. It might seem counterintuitive, but the goal of getting more 18-64 year-old people to get vaccinated is to keep them out of the hospital so physicians can focus on the two age groups that can have serious complications from the flu, namely the elderly and infants/children.

A moat of opportunity
Because only around half of consumers tend to get a flu shot in a given year, and the evidence has shown that getting a flu shot will likely reduce the severity and/or length of your flu illness, there's a lot of opportunity to improve flu vaccination follow-through This would be good news for consumers as it'd likely mean fewer hospital visits and possibly even fewer influenza-related deaths, but it'd be great news for flu vaccine manufacturers.

Source: Jim Gathany, Centers for Disease Control and Prevention.

There are four primary flu vaccine manufacturers – AstraZeneca, Sanofi (SNY -2.27%), Novartis (NVS 1.10%), and GlaxoSmithKline (GSK -0.92%) -- and many are working with a new formulation this year known as the quadrivalent. In previous years a trivalent influenza vaccine was developed which was geared at protecting consumers against the projected two most common type A influenza strains and the most common type B influenza. The new formulations were developed to protect against the two types of A and B influenzas expected to dominate in the current year. Although the CDC does not note a preference between the two vaccines, the quadrivalent formulation, at least on paper, should help appeal to more people.

AstraZeneca's FluMist quadrivalent certainly tops the list for patients who are afraid of a needle, but sales of the intranasal spray haven't been up to par because the price of that convenience is often much higher than simply getting a shot. Instead, GlaxoSmithKline's FluLaval and Fluarix quadrivalent, Novartis' Fluvirin trivalent, and Sanofi's Fluzone are dominating.

GlaxoSmithKline and Novartis' flu vaccines are on pretty equal footing. Flu vaccine sales for the two drugmakers were nearly identical in the 2011-2012 season with Glaxo's Fluarix approved in children as young as three and Novartis' Fluvirin trivalent approved for children as young as four.

The standout, though is Sanofi's Fluzone which offers the consumer a number of advantages. First, Fluzone can be administered in patients as young as six months old, meaning Sanofi pretty much has the sub-three year-old market cornered. The company also has the perfect go-between for the needle squeamish with an intradermal vaccine that sports a needle which is 90% shorter than a traditional needle. In addition, Fluzone comes in six different dosages, because frankly we're not all the same height and weight. In terms of covering the consumer, Sanofi's Fluzone is simply unmatched. If the CDC can translate its vaccination concerns to the consumer and vaccination rates begin to rise, Sanofi would likely be the prime beneficiary.

Editor's Note: A previous version of this article referred to Fluzone as an intradermal patch. The Fool regrets the error.