Why is the 2017-18 flu season is looking bad? Plenty of things to blame

We have just passed the halfway point of the 2017-18 flu season, and if you are watching the news, you could get the impression that things are pretty bad. CDC reports that for this week, the cumulative hospitalization rate was 51.4 per 100,000, which is higher than the 43.5 per 100,000 reported at this same week during the 2014-2015 season. If that trend continues through the season, the number of influenza hospitalizations may exceed 710,000.

Furthermore, the CDC provided evidence of how bad this flu season actually is:

Last week, the number of people even in the clinic that had influenza-like illness was 6.6%. This week it is 7.1%. We’ve had two seasons in the last 15 years that were higher than that. The first was the 2009 H1N1 pandemic, which peaked at 7.8% and the 2003-2004 season, which was a high severity H3N2 season, which peaked at 7.6%.

Furthermore, at least 53 children, under the age of 18, have died of influenza or complications of the virus. And because reporting lags by a few weeks, the numbers are undoubtedly going to be higher. These are all families that have to deal with a tragic loss of a child from a disease that many anti-vaccine people classify as “not dangerous.”

Because there is a lot of myths and tropes out there about the 2017-18 flu season, I thought I would list out some of the reasons why it’s so bad – but it’s mostly your fault. 

You’re not getting vaccinated

Because of ridiculous myths about the flu vaccine in general, the uptake of the flu vaccine has always been lower than almost every other vaccine. According to CDC statistics from 2015-16, the latest available, flu vaccine uptake was about 59.3% for children and 41.7% for adults, far below the level necessary for the herd effect.

There are a lot of reasons why people don’t get vaccinated:

  • The flu isn’t dangerous. Except it is, as we showed in the introduction to this article.
  • You can catch the flu from the flu vaccine. No, you can’t.
  • It’s too expensive. Not really, compared to the cost of catching the flu, but almost every health insurance plan covers it, and Medicaid and the Vaccines for Children Program covers it for children.
  • You are allergic to eggs. No, that’s not an issue anymore.
  • You are pregnant. Getting the flu vaccine while pregnant actually improves fetal and maternal outcomes.

And I could go on and on about all the excuses to not get the flu vaccine, but all of them are easily refuted with a bit of science and bunch of common sense. By not getting vaccinated, the flu virus gets to spread unimpeded to those who are at most risk from the effects of the flu – those with chronic diseases, the elderly, and children.

Special 2017-18 flu season excuse for not vaccinating

There continues to be a myth across the internet that the current vaccine is “only 10% effective.” Even my daughter, who is a fully vaccinated (including the full series of HPV vaccines) adult studying science at one of the best universities in the country, used that excuse on me. And I thought I raised her better.

I previously debunked this belief about the 2017-18 flu season vaccine thoroughly. Let me recount the key points I made:

  1. The current quadrivalent flu vaccines contain antigens for 4 flu viruses – two types of influenza A, H1N1 and H3N2, and two types of influenza B, B/Phuket/3073/2013–like virus (Yamagata lineage) and B/Brisbane/60/2008–like virus (Victoria lineage). 
  2. The vaccine is highly effective against all but influenza A H3N2 virus. It is very important to be protected against all circulating flu viruses. The CDC estimated that the vaccine is over 70% effective against the two influenza B viruses, and over 60% effective against the H1N1 variant.
  3. The vaccine has unknown effectiveness against the H3N2 virus, but according to an analysis by the Australian government, the effectiveness may be as high as the upper 30% range.
  4. Actually, using early data, the CDC estimates the current flu vaccine’s effectiveness against the H3N2 strain could be around 30%. Still not great but it is 3X higher than the tropes circulating about the current vaccine.

Even if the H3N2 component is only 10% effective, and most of the evidence disputes that low of a number, the vaccine still reduces the risk of death for children, for those with chronic diseases, and for seniors. I know that some anti-vaccine folks dismiss even saving one death as important, but I have more concern for humanity – reducing the risk of death is important.

What brilliant scientist created the H3N2 issue?

You might be asking what is the problem with the H3N2 component of the vaccine – and it’s not science’s fault. I wrote a detailed summary of the process to decide on antigens for flu vaccines in the Northern and Southern hemispheres (which can be different, since flu strains may vary between areas of the world).

Essentially, the antigens for the flu vaccines are chosen by the world’s leading public health agencies six months ahead of the start of flu season, because that’s the amount of time manufacturers require to produce and ship the vaccine across the world. Mostly, the scientists who decide on these strains get it right.

Unfortunately, flu viruses do mutate from year to year, even within a few months. And the H3N2 variant appears to have a higher rate of mutation than other flu viruses, so there is a greater chance that the vaccine will have different antigens than the circulating H3N2 flu.

Finally, the story gets a bit worse. It appears that when the H3N2 flu variant is grown in chicken eggs, as are all flu viruses used in vaccines, it mutates at a different rate than the wild-type virus. Thus, the vaccine’s H3N2 antigens could be quite different than the variant circulating among humans.  In other words, a mutation in the H3N2 strain meant most people receiving the egg-grown vaccine didn’t have immunity against H3N2 viruses that circulated last year. This makes the current flu vaccine less effective against the H3N2 strain dangerous during this 2017-18 flu season.

Now, science is working on this problem. Some manufacturers are growing the flu viruses in mammalian cells, where the virus doesn’t mutate nearly as quickly as it does in eggs. This should improve the H3N2 portion of the vaccine in the upcoming years, but I know, it doesn’t provide much relief to our current 2017-18 flu season.

Given all of this, why bother?

There are a few easy reasons why you should get the 2017-18 flu season vaccine. Let’s list them out:

  1. The 2017-18 flu season vaccine might work for you. And even if you catch the flu in spite of being vaccinated, the vaccine may reduce the severity of symptoms. People who get the flu vaccine and then catch the flu often have a shorter and easier course of the disease.
  2. The vaccine is very effective against circulating H1N1 and two influenza B viruses. Those are still dangerous cases of flu, and the current vaccine gives you and your children excellent protection.
  3. If the CDC estimate of the H3N2 portion of the vaccine is accurate, around 30%, it can reduce the risk of the H3N2 flu by a substantial amount.
  4. It is not too late to get the vaccine and protect yourself against the flu.

You really have two choices here. You can believe the trolls regarding flu vaccine effectiveness, ignore the vaccine and put yourself and loved ones at risk of significant dangers from the flu. Or you can listen to the CDC, public health specialist, and yours truly, get the vaccine, and you increase your chance to avoid the dangerous flu. I don’t do false dichotomies, so it’s really a binary choice. I hope you choose wisely.


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The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!