Every year, it appears that flu season starts earlier and earlier, and somehow, every year, the virus mutates into its "most virulent form ever." Sometimes it's a wonder we even survive with the way that news stations discuss the near-plague that sweeps across the country beginning every fall and extending into winter. Yet, we persevere based on a combination of factors, including good genetics, healthy eating habits, making smart life choices, and, supposedly, in some cases, by getting a flu shot.

Keep that needle away, Doc
The jury has definitely been shown both sides of the coin when it comes to the effectiveness of annual flu vaccines. On one hand, physicians will admit that the flu shot is not a cure-all potion that will prevent the flu. Researchers, each year, must take their best guesses based on the data available on what strains of the flu will be circulating and hope that they've given flu vaccine manufacturers the proper guide to protect our growing, and aging, population. These guesses are often fairly accurate, but they don't produce perfect results.

There's also quite a bit of skepticism regarding the effectiveness of existing flu medications like Tamiflu, which was developed by Gilead Sciences and licensed to Roche (RHHBY 0.89%). In November, a researcher linked to the British Medical Journal called for European Union nations to sue Roche for not divulging all of its Tamiflu records in 2009 when requested. Roche countered by noting that it released all pertinent legal information, but refused to release confidential patient-level data to the BMJ researchers. The World Health Organization added Tamiflu to its "essential medicines" list, which resulted in many countries stockpiling the medication. However, the vaccine is simultaneously being investigated by the European Medicines Agency (Europe's version of the Food and Drug Administration) for not reporting the side effects -- including deaths -- for 19 separate drugs, including Tamiflu, used on approximately 80,000 people in the U.S. 

The numbers don't lie
On the other hand, the Centers for Disease Control and Prevention have made it quite statistically clear that there exists demonstrable evidence that flu shots serve a benefit to the greater population. Whether it be in reducing the severity or longevity of the illness, or building the body's immune system up to support against the virus, the CDC is clear in recommending that people over the age of six months get vaccinated annually.

The CDC posted its mid-season update for 2012-2013 on this year's vaccine effectiveness (known as VE) on Feb. 21. To my astonishment, the figures were actually quite encouraging. The CDC's VE estimate for protection all age groups was 56%. This year's vaccine was 47% effective against flu A -- the H3N2 virus, which is the most common virus this season – and 67% effective against flu B. These results might underwhelm some of you, but the end result is that patients who developed flu A had their chance of hospitalization due to illness reduced by roughly half, while flu B patients had a nearly two-thirds reduction in their chance of hospitalization.

Should you get the shot?
Statistically speaking, the numbers don’t lie and the benefits of a flu shot do outweigh the risks involved. However, what I found shocking that is that despite the insistence of the CDC in encouraging the elderly to get vaccinated, it's this group of aging Americans that gains the least statistical benefit from the vaccine.

According to that same report on vaccine effectiveness above, just 9% of persons aged 65 demonstrated VE to the H3N2 virus. This means that hospitalizations for the elderly are being reduced by 9% -- no ignorable figure -- but that the effectiveness of the vaccine is tame in those with compromised immune systems.

The irony with the flu shot is that it's really targeted at young, healthy adults who already have a good shot at dealing with the effects of influenza to begin with. Sure, it helps keep many from developing serious side-effects and keeps them out of the hospital so resources can be focused on aiding the elderly and those who really need medical care, but it's a shocking revelation.

What does this mean for vaccine manufacturers?
The data represents both a boon and a bust for flu vaccine manufacturers. With much of America still youthful and healthy, a whopping 64.8% of Americans had declined to get a flu shot as of November, according to The Washington Post. This isn't surprising, as flu shots consistently represent some of the lowest vaccinations rates each year. Data from the past three years on vaccinations rates from the CDC is hardly encouraging:

Source: Centers for Disease Control and Prevention.

I believe some of this plays into common misconceptions that the flu shot will make you sicker, as well as the fact that researchers are doing nothing more than giving you their best guess as to which strain will be dominant this year. Without certainties, more people than the CDC would like are opting not to get vaccinated.

Conversely, this represents a major growth opportunity for flu vaccine makers. These include:

  • FluMist by AstraZeneca (AZN 0.68%): This is the only nasal spray approved by the FDA, and, according to AstraZeneca, it produced 12 million doses for this year's flu season. Despite having no needles involved, sales of FluMist haven’t taken off as many analysts had expected.
  • Fluzone by Sanofi (SNY 1.53%): As of January, Sanofi's Fluzone had sold better than expected, with the company producing 60 million doses and selling out of certain aspects of its immunization therapy. Fluzone comes with a particularly shorter and less intimidating needle, which induces less apprehension over "getting a shot."
  • Fluvirin by Novartis (NVS 1.48%): Novartis' Fluvirin shipped roughly 36 million doses through mid-January and works in similar fashion to Fluzone. One of the big difference is its approval, which ranges from age 4 and up, versus Fluzone, which can be used in infants as young as six months.
  • Fluarix, Flulaval, and Relenza by GlaxoSmithKline (GSK 1.18%): Flulaval is a vaccine that Glaxo has been supplying regularly for nearly a decade. Fluarix is an "upgrade" approved in December by the FDA to help treat against both types of A-strain and B-strain flu instead of just both A strains and one strain of B flu. Production of the vaccine is expected to begin for the 2013-2014 season. Relenza is a medication, similar to Tamiflu, that helps lessen the length and severity of flu-related symptoms.

Get the shot, feel better, and possibly make some money
If simply 10% more of the population were to immunize themselves against the flu each year, these four companies would need to produce more than 30 million additional doses. This would be particularly beneficial for Sanofi's Fluzone, Novartis' Fluvirin, and Glaxo's vaccine and drug trio, which have predominantly ruled the flu market in 2012-2013.

The flu shot isn't a perfect science, but it's a collection of the best data researchers have at any given time that could help keep you out of the hospital and keep you healthier. It isn't a cure-all, but it definitely can't hurt your chances by getting immunized. Between the growth opportunity for vaccine makers, which could turn into a healthy investment return and better health all around, getting a flu shot never looked like a smarter idea!