Here's Why This Year's Flu Vaccine Isn't Working

By Markets Fool.com


Source: Flickr user Esparta Palma.

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A lot of attention has been paid to Ebola over the past year, and with good reason; around 40% of those who contract the disease will wind up dying from it, based on statistics from the World Health Organization. However, in the grand scheme of things, influenza and pneumonia are of far greater concern when it comes to global deaths.

Within the United States, pneumonia and influenza are the eighth-leading cause of mortality, with nearly 54,000 deaths reported in 2011, per the Centers for Disease Control and Prevention. This year has been particularly worrisome with flu season starting earlier than normal and the CDC in recent weeks declaring the flu to be a pandemic. As you can see below, about half of all U.S. states are currently experiencing high influenza-like illness activity.


Source: Centers for Disease Control and Prevention.

The most common way that the CDC suggests consumers battle the flu is to get a flu shot. Unfortunately, according to a CDC press release earlier this week, the flu shot isn't very effective this year.

Why isn't the flu vaccine working?
Early estimates on seasonal influenza vaccine effectiveness, or VE, from the CDC came in at a paltry 23%.

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Based on commentary from the CDC, the reasoning the VE is so low this year relates to the emergence of an A-influenza strain (H3N2) just before flu season kicked off and well after pharmaceutical companies had begun making this year's vaccine. As ABC News reported earlier this month, the H3 subtype is the one most associated with flu-related deaths, thus why this year's flu has seemed so severe compared to other recent years.

Many of you might be wondering, "Why can't vaccine manufacturers simply fix this and put out the correct vaccine?" There are three reasons why they can't and why this year's vaccine simply isn't working as well as the CDC hoped it would.

Source: Flickr user Yasser Alghofily.

First, researchers have to make educated guesses as to what strains of the flu are likely to predominate in the upcoming year. ABC News reports there are 17 different types of H particles that allow the flu virus to bind to cells and nine different kinds of N particles that determine how it spreads throughout the body. In other words, there's little leeway in researchers' guesses because the standard trivalent or quadrivalent flu vaccine is only going to protect against two influenza A and two influenza B strains, yet there are far more types of flu viruses. Despite this guess work, researchers have been right more years than they've been wrong.

Secondly, pharmaceutical companies need time to manufacture the vaccine ahead of flu season. Typically the peak of flu season runs from November to March, meaning pharmaceutical companies need to begin manufacturing the vaccine by June or July in order to have it ready for a late August or early September shipment. If a different strain emerges, these pharmaceutical companies simply don't have the ability to backtrack and get enough vaccines available in time for the peak of flu season. All they can do is go off of the best guess of researchers.

Finally, the flu is an infectious disease that's prone to mutations from time to time. This means it can throw curveballs at researchers, and new strains can emerge without warning. This has a tendency to make pharmaceutical companies want to hold off on producing too much of a vaccine for fear that it could wind up useless because of a mutation.

Combined, these three factors sum up why this year's flu vaccine didn't work.

Source: Flickr user KOMUnews.

But, in defense of the CDC, a VE of 23% certainly isn't final; this is just an early assessment. It's possible the VE could improve as the remainder of flu season progresses. It's also worth noting that while the vaccine worked in fewer people than previous years, it still kept 23% of flu patients out of the doctor's office, potentially freeing up doctors to help those whose immune systems are weaker, such as children and the elderly.

Additionally, the quadrivalent vaccines produced this year should help protect against type B influenza strains that tend to show up later in the flu cycle. So even though this year's VE is low, the CDC is still recommending people to get a flu shot.

The push for antivirals
With researchers right more often than they've been wrong in recent years, we haven't seen antiviral drugs designed to shorten or lessen the severity of the flu get much play. However, this year could be different.

Two notable antiviral drugs that could see increased importance areGlaxoSmithKline's(NYSE: GSK)Relenza and Roche's Tamiflu, which was developed by Gilead Sciences.

Tamiflu is a pill or liquid formulation and by far the more popular choice of the two, whereas Relenza is an inhalable powder. Relenza's inability to be used by people with breathing problems like asthma or COPD likely puts it behind Tamiflu even though both are out to achieve the same goal.


Source: Flickr user Tony Hisgett.

The secret to antivirals' success is they need to be administered no more than two days after the flu-like symptoms began. These drugs work by attacking the flu virus and preventing it from multiplying in your body. The result should be a one or two day shortening of your flu-like symptoms. More importantly, these drugs are designed to help prevent complications from the flu, such as pneumonia, where the real danger with influenza lies.

In case you've forgotten, when the swine flu pandemic hit in 2009, sales of Tamiflu shot through the roof to roughly $3 billion for the year. Since then, sales have cooled to closer to $1 billion per year. It's possible that Roche could see a sizable surge if VE statistics remain as low as they are right now. GlaxoSmithKline would also likely benefit, but to a much smaller degree, as Relenza sales have only totaled $62 million through the first nine months of 2014.

For now we can only watch and wait for additional CDC flu statistics, but it's clear from the initial VE and this year's primary strain (H3N2) that we could be in for one of the more severe flu seasons that we've seen in quite some time.

The article Here's Why This Year's Flu Vaccine Isn't Working originally appeared on Fool.com.

Sean Williamshas no material interest in any companies mentioned in this article. He currently has the flu but is too stubborn to get into bed. You can follow him on CAPS under the screen nameTMFUltraLong, track every pick he makes under the screen nameTrackUltraLong, and check him out on Twitter, where he goes by the handle@TMFUltraLong.The Motley Fool recommends Gilead Sciences. The Motley Fool owns shares of Gilead Sciences. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.