The flu vaccine is working well this year. It's not too late to get it.

Current flu trends for 2018-19. Brown shows H1N1 strains,
red shows H3N2, and yellow indicates the strain was not
genotyped.

The flu is widespread and increasing right now, according to the CDC.  At least 42 states were reporting high levels of flu activity as of the end of December 2018, and the rates are still climbing. In other words, we're in the midst of flu season.

Other than that, though, the news is relatively good. Here's why.

First, the dominant strain of flu this year is H1N1, which is the "swine flu" that first appeared as a pandemic in 2009. But pandemics don't have to come with high mortality rates, and as it turned out–luckily for humankind–the 2009 flu was milder than the previous dominant strain, H3N2, which first appeared way back in 1968.

This season, nearly 90% of the flu cases tested by the CDC are turning out to be H1N1, the milder variety. Although 10% of people are still getting the much-nastier H3N2 flu, it's good news compared to last year, when H3N2 dominated.

Back to the bad news (although this is old news): the 2009 swine flu (H1N1) didn't completely displace the older flu strain. Instead, we now have both types of influenza circulating, along with two strains of the even milder influenza B virus. Since 2009, the flu vaccine has to combat all 4 of these flu viruses, which is why you might see the term "quadrivalent" associated with the vaccine. That just means it targets all 4 different strains.

Back to the good news again: the vaccine this year contains just the right strains! This doesn't always happen; actually it happens much less frequently than anyone would like. But now that the flu season is under way, the CDC can test the circulating flu viruses and compare them to the strains that are targeted by this year's vaccine. This year, both the H1N1 and the H3N2 viruses match the vaccine strains really well, which means that if you got the shot, you are likely to be very well protected.

(Keep in mind that even in a good year, the vaccine isn't 100% effective, and you can still get the flu. But you are much less likely to get it than anyone who is unvaccinated.)

While I've got your attention, let me answer one of the top 10 health questions of the year: "how long is the flu contagious?" According to the CDC,

• the flu is most contagious in the first 3-4 days after becoming sick.

It continues to be contagious for up to a week, so if you have the flu, stay home! And make sure those around you avoid physical contact, as much as possible, and wash their hands frequently.

And while I'm at it, let's debunk a common myth:

• No, you can't get the flu from the vaccine.

So if you've put off getting the flu vaccine, it's not too late! The season is in full swing, but if you get the vaccine today, you'll likely have excellent protection for the rest of the season. Go get it.

At the movies: popcorn and anti-vaccine fearmongering

The anti-vaccinationists have launched a new campaign this holiday season to spread cheer – oops, I mean fear – to moviegoers everywhere. Yes, the folks at SafeMinds and Age of Autism have produced an advertisement that they are trying to place in AMC theaters across the country. In fact, they almost succeeded, but quick action by skeptical science bloggers at SkepChick, Respectful Insolence, and their readerships convinced AMC to cancel the ad – for now.

The ad that SafeMinds is trying to run is intended to scare people away from getting their flu vaccine, just as flu season is beginning. The vaccine this year will protect you against both the new “swine” flu, called H1N1, and the previous flu strain, H3N2. Early data from the CDC makes it clear that both strains are still around, with H3N2 showing up somewhat more frequently so far this fall. The vaccine not only protects you, but also your family, your colleagues, and the many other people you might come into contact with each day while at work, shopping, or elsewhere.

Why try to scare people? Well, the people behind SafeMinds and Age of Autism believe that the preservative thimerosal, which is used in some but not all flu vaccines, causes autism. This theory has been thoroughly investigated over the past 10 years, and just as thoroughly discredited. In fact, it never had any positive evidence to support it in the first place, but it has been promoted aggressively by a journalist, David Kirby, who made his fortune off a book based on the thimerosal-autism hypothesis. (I’m not providing a link – Kirby has already made far too much money off this bogus claim, and I don’t want to give him the web traffic.)

Thimerosal was introduced into vaccines in the 1930s, and it is a very effective means to prevent the growth of bacteria without affecting the potency of the vaccine itself. In over 60 years and hundreds of millions of doses, it has proven to be quite benign. Nonetheless, it contains a form of mercury called ethylmercury, which anti-vaccinationists claim causes autism and other neurological disorders.

The claim that thimerosal causes autism was the central question of a large, multi-year Autism Omnibus trial, which ruled definitively last year that thimerosal does not cause autism. I wrote about that ruling at some length back in March, and I won’t repeat it here, except to quote again from the Special Master’s decision:

“The numerous medical studies concerning the issue of whether thimerosal causes autism, performed by medical scientists worldwide, have come down strongly against the petitioners’ contentions. Considering all of the evidence, I find that the petitioners have failed to demonstrate that thimerosal-containing vaccines can contribute to the causation of autism.”

The anti-vax crowd will not give up, unfortunately. Rather than spending their time and effort trying to find the true causes of autism, they continue to repeat claims that have already been shown false. For example, the SafeMinds website lists 5 “key points” that are just flat-out wrong. Here are the first two:

1. “The autism epidemic that began in the late 1980’s is likely due primarily to toxins adversely affecting fetus and infants during development.” Wrong, in at least two ways. First, there is no autism “epidemic.” The best evidence today indicates that the rising rates of autism are due to a combination of factors, primarily (a) rising rates of diagnosis due to increased awareness among physicians and patients and (b) a dramatically broader medical definition of autism that was introduced in the early 1990s.
2. “Mercury is likely a major contributor to this toxin-induced autism, whether the source of the mercury is from vaccines or environmental mercury exposure.” Wrong again. This is the claim that was so thoroughly refuted in the lengthy Autism Omnibus trial, with hundreds of pages of testimony from dozens of experts, and epidemiological data from literally hundreds of thousands of people.

But data doesn’t seem to have any effect on the anti-vax zealots at Age of Autism and SafeMinds.

Because AMC refused to run their ad, Age of Autism is telling its readers to stay away from AMC theaters this holiday season. I hope they do! Why? Because these unvaccinated individuals are a genuine threat to public health. Movie theaters, and the malls in which they are located, are an ideal place for infectious diseases to spread. Without vaccines, countless thousands of people would fall ill every holiday season after mingling with other shoppers, and some would likely die. My message to the unvaccinated crowd at SafeMinds is: stay away from the rest of us.

And I encourage everyone else to get your flu shot, get your kids vaccinated, and then go see a movie at an AMC theater. Meanwhile, you can also tell them at this link that you appreciate their taking a stand against misinformation and for the benefit of public health.

The flu pandemic may be over, but it wasn’t a hoax

It’s over. Or it’s nearly over. The great influenza pandemic of 2009 – often called the swine flu – has peaked and declined, and it might be over until next year. Not only is it over, but in a remarkable demonstration of evolution at work, it may already have pushed the “old” seasonal flu out of the human population.

Don’t get me wrong: it could still come back in a second wave, as epidemiologists at the CDC and the WHO have been warning. They’re right, too: we just don’t know enough about this pandemic to be sure it’s over. Dr. Keiji Fukuda from the WHO said on Thursday:

“We see that activity is declining or has declined but we also continue to see in these areas a transmission of the virus, so it has not disappeared, and it is has not gone back to baseline. Based on the situation, our current assessment is that it remains too early to say that the pandemic is over. And it is unclear whether we will see in the northern hemisphere over the next few months during the winter and spring period another significant wave of activity.”

Further down in this post I’ll show why I think it’s over. I think this is great news, but not surprisingly the conspiracy theorists have to make some wild claims to grab attention while there’s still time. Let me address them first.

As reported in the Irish Times, the UK Daily Mail, and elsewhere, the WHO is being accused of inventing the pandemic in order to boost the profits of drug makers. Where did this conspiracy theory come from? Why, my old friend Wolfgang Wodarg, head of health at the Council of Europe:

“Council of Europe parliamentarian Wolfgang Wodarg called for an inquiry into what he called a `false pandemic' and the way it was handled at national and European levels, claiming pressure from pharmaceutical firms.” (Source: Irish Times)

Wodarg’s resolution calling for an investigation was just passed by the Council of Europe.

The last time I wrote about Wodarg, he was claiming that the flu vaccine causes cancer. As I wrote then, Wodard doesn’t know beans about the flu. Anyone who makes such unfounded, irresponsible claims deserved to be ignored, but because he’s a high-profile politician, the WHO had to respond. Dr. Fukuda, speaking for the WHO, said:

“The allegation by some, that the H1N1 pandemic is a fake is both scientifically wrong and historically inaccurate.”

As for the conspiracy claim, he said

“WHO has reached out to all parties who could help to reduce harm from the pandemic but we did take very great care to make sure that the advice received was not unduly influenced by commercial or non-public health interests.”

As for whether it was real, this map shows the deaths caused by pandemic flu this year:
You don’t have to be an epidemiologist to see that this has been a worldwide pandemic, with plenty of deaths. And keep in mind that these are just confirmed deaths due to flu; in many countries where surveillance is minimal or non-existent, we have no idea how many people were infected. It’s true that the number of deaths has been much lower than we feared, but back in the spring of 2009, no one knew how virulent this strain would be.

What I’d say to Wodarg (and what Dr. Fukuda might have wanted to say) is: Wodarg, you don’t know what you’re talking about. Your irresponsible claims are doing more harm than good. If you truly care about public health, then educate yourself before you speak out on the flu next time.

Now, why am I saying the pandemic is over? Well, in the U.S., the weekly surveillance reports from the CDC paint a very clear picture: the flu peaked in October and then declined rapidly, much like the seaonal flu does every year. Normally the peak occurs in January or February. Take a look at the latest data:
In the past three pandemics, in 1918, 1957, and 1968, our surveillance wasn’t nearly as good, so maybe there will be two flu seasons this winter. It could happen – we could get a second wave – but I’m putting down my $0.25 that it’s over.

Notice something else about this figure? The normal seasonal flu hasn’t been seen at all! The graph shows that virtually all cases are pandemic H1N1 flu. In contrast, here are the past 4 years of flu seasons: See what I mean? Just one peak each year, and the color-coding shows that the normal seasonal flu is a mixture of H3N1, an older H1N1 (not the new strain), and influenza B.

How about Europe? It’s fading there too: the European CDC report for January 15 says

“Sentinel physicians collected 735 respiratory specimens, of which 139 (19%) were positive for influenza virus. This proportion has now decreased for the seventh consecutive week. … Of the 15 486 influenza viruses detected by sentinel networks and subtyped since week 40/2009, 15 393 (99%) were the pandemic virus."

So in Europe too the pandemic is on the wane, and the normal seasonal flu strains are virtually absent. For those who follow the evolution of the flu, this is quite remarkable. It means that exposure to pandemic H1N1 provides protection against all three of the seasonal flu strains, and it suggests that a large proportion of the population has been exposed to pandemic flu – otherwise, more people would be getting sick with seasonal flu. Pandemic H1N1 has out-competed the old strains in less than a year – the blink of an eye in evolutionary time.

So I think it’s over. But get your H1N1 flu shot! I just got mine. Why? Well, there is a small chance of a second wave, and there’s no downside to the vaccine: after 60 million flu vaccinations in the U.S., there hasn’t been a single reported case of injury due to the vaccine. In addition, the flu might come early again next fall, just as it did this year, and a vaccination now will likely protect you through next season. And finally, don’t forget that vaccinating yourself is also protecting your family, friends, and community.