The mRNA vaccines are defeating COVID. Let's use them for the flu.

 

The last year has been a story of triumph in the vaccine world, with the rapid development of two highly successful vaccines for Covid-19, one developed by Moderna and the other by Pfizer and BioNTech. Now that flu season is approaching, why are we still using 50-year-old technology for the flu vaccine?

The reason the Covid-19 vaccines were developed so quickly is that they used a new, much faster and easier-to-create type of vaccine technology, based on messenger RNA, or mRNA. What’s even more exciting is that we now have an overwhelming amount of evidence, from real-world experience, that these vaccines are remarkably safe and effective.

Now, anti-vaxxers and the “vaccine hesitant” are claiming they don’t trust the vaccine because it was developed too fast. That’s ridiculous: the real reason they don’t trust the vaccine is because they’re consuming a steady diet of anti-vaccine nonsense, promoted by a combination of right-wing media and the Disinformation Dozen (who include left-wing as well as right-wing zealots). But let’s not go down that rabbit hole today.

So what is an mRNA vaccine? Here’s a brief explainer, and then we’ll look at the flu vaccine. (Note: feel free to skip ahead if you already understand the technology.)

Messenger RNA vaccines have been under development for decades, since long before Covid-19 appeared. The technology required a series of breakthroughs over the years, as described in a recent Nature news story, and many scientists contributed. It wasn’t used in vaccines in part because it wasn’t ready, but also because we rely on private companies to develop vaccines, and few of them were interested in investing in a new, not-yet-approved technology. But I digress.

Messenger RNA is the stuff that all of your cells use to translate your genes, which are encoded in DNA, into proteins. The basic process is that the DNA for a gene is copied into pieces of mRNA, where the DNA letters, ACGT, are replaced by slightly different (chemically) RNA letters, ACGU.

Every cell in your body is filled with mRNA, all the time. It’s the stuff of life, so of course it is totally safe. Each cell uses mRNA to make proteins, which do most of the actual work that keeps you alive.

Here’s the brilliant thing about mRNA vaccines: all they do is introduce some mRNA into your cells that encodes a single protein from the virus, which is called “Spike” in the case of the Covid-19 vaccines.

Your own cells then make the Spike protein, but they don’t make very much! They just make a few copies, because mRNA doesn’t last very long. And because there is no DNA copy of the Spike protein in your genome, once the mRNA in the vaccine breaks down, it’s gone forever.

The other brilliant thing is that your own immune system recognizes Spike as a foreign protein, and it generates cells that will recognize any future infections where the Spike protein is present. If you’re later infected by SARS-CoV-2 (the Covid-19 virus), your immune system is primed and ready, and in a large majority of cases it attacks and destroys the virus before you get sick.

So that’s it: an mRNA vaccine is simply a little package made of fat molecules (called liposomes) that contains a few copies of mRNA encoding a viral protein. There’s nothing to prevent us now from creating similar vaccines for the flu, or for other viruses where we need new vaccines. (In the case of flu, we can use mRNA for a gene called hemagglutinin, but again I digress.)

We make new flu vaccines every year, because the flu is constantly mutating. Most years, the flu vaccine isn’t a great match for the circulating strains of the virus, and therefore the vaccine isn’t very effective. In a good year it might be 60-70% effective, but in bad years it might be much worse. A big part of the problem comes from how we create the vaccine.

In the U.S., we make most of our flu vaccines by growing influenza viruses in chicken eggs. No, I’m not making this up. Around February of each year, a panel of experts selects 4 strains of the virus that they think will most likely match the viruses for the following flu season, which usually ramps up in November or December. (Here are this year’s choices.)

Once the experts have selected the vaccine strains, the manufacturing process begins, first by checking to see if all 4 strains will grow robustly in chicken eggs. If they don’t, the panel may have to switch to different strains that are less likely to work. No, I’m not kidding: the success of the flu vaccine depends on how well it grows in eggs. That’s one reason why, in some years, the flu vaccine is a flop. This would simply never happen if we used mRNA technology.

With mRNA vaccines, we don’t have to grow any viruses at all. The mRNA from a single gene–hemagglutinin for influenza–can simply be synthesized in large quantities, just as we’re now doing for the Spike protein in SARS-CoV-2. Or for an even more effective vaccine, we might add the gene for neuraminidase, the other protein in influenza that our immune system can “see.”

An mRNA vaccine for flu would be far cheaper to manufacture, not requiring huge chicken farms. (This year, 82% of flu doses in the U.S. were made this way.) Even more important, though, is that an mRNA vaccine for flu would likely be far more effective at controlling the severity of the infection itself.

Why aren’t we doing this already? Simply put, it’s because we rely on private companies to take the initiative, and it’s not worth it to them to test and validate an entirely new vaccine, which requires a substantial investment. There’s also a simple solution, the same one we used for Covid-19: the government should take the lead.

We’re now at the beginning of flu season, which almost disappeared last year thanks to our social distancing and masking behavior. I’ve had my flu shot, and millions more are being administered around the world. Just last week, an early report out of Europe indicated that the flu season this year might be “severe,” which is the last thing we need with Covid-19 still raging.

We don’t yet know if this year’s flu shot will be effective or not, but odds are, based on past performance, that it won’t be great. (It’s still much better than nothing, I should add.) If we want a better flu vaccine, now is the time to start developing a new one using mRNA. If private industry doesn’t step up, any one of dozens of countries have the expertise to do so instead.

We've totally crushed the flu virus this year

 As awful as the Covid-19 pandemic is, it’s given us at least one benefit: we’ve utterly crushed the flu virus.

That’s right–the flu has almost completely disappeared this year. A combination of social distancing, closed schools and businesses, dramatically reduced travel, and high flu vaccination rates has achieved something that most flu experts never thought possible.

Flu levels are so low, in fact, that one has to wonder if the flu will even come back next year. The levels now are far lower than we’ve ever seen in modern history. Let’s take a look at the numbers:

nfluenza cases reported to the CDC by US public health laboratories, 2020-2021 season. Data from the CDC, graph created by the author.

As you can see here, the very worst week had just 24 confirmed cases in the entire U.S. That is truly astonishing. And in 2021 so far, we’ve had 5 or fewer cases in the entire country each week. Basically, the flu is gone. To see how dramatic this is, let’s look at data from last year (the winter of 2019-2020), which was a typical flu season:

Influenza cases reported to the CDC by US public health laboratories, 2019-2020, season. Data from the CDC, graph created by the author.

As you can see above, the U.S. had about 3,000 cases per week in January and February of 2020, with a peak at nearly 4,000 cases.

The rate of influenza this year is over 100 times lower than it’s ever been. Why did this happen? It’s obvious: all of the precautions we’re taking to reduce the spread of Covid-19 have worked wonders to prevent the flu as well. In fact, they’ve worked far better for influenza than for the Covid-19 virus.

No one knows what the flu season will look like next year, but for now, at least we’ve won a clear victory against the influenza virus. That’s a bit of good news.

The flu is getting worse, just as the government shuts down.

Uh oh, this is not good.

The flu season is looking particularly bad this year. We already had signs of trouble back in November and December, when it emerged that the flu vaccine was not very effective against the dominant strain that is circulating this year, which is called H3N2.

Until this past Friday, it seemed that the peak of the flu season might have occurred just around the new year, as shown in this chart from the CDC:

The chart shows a peak in the very last week of 2017, and then the number of reported cases seemed to decline. But then on Friday the CDC reported this alarming trend:

That red line spiking upward in the middle of the chart shows the number of flu-like cases reported by the CDC's national network this year. Rather than going down, the trend shows a sharp rise over the past two weeks. We don't know exactly what it is (these are not laboratory-confirmed flu cases), but more people are getting sick.

Even more alarming are the reports of young, healthy people dying of the flu. This past week the Washington Post reported on a healthy 10-year-old boy who caught the flu and died within just a few days. Just before Christmas, a healthy 21-year old young man in Pennsylvania came down with the flu, and went rapidly downhill until he was rushed to the emergency room on Dec. 27. The hospital was unable to save him, and he died the next day. These cases are truly alarming, and even though the CDC hasn't seen a statistically significant increase in deaths among young people (not yet, at least), everyone needs to take the flu very seriously this year.

With the government shut down, a difficult situation becomes worse. Most of the CDC staff will be forced to sit on their hands when they could be working–and many of them want to work, but they won't be allowed to. What's especially frustrating (and wasteful) is that the U.S. will almost certainly pay all federal employees for this forced time off, as it did in previous shutdowns.

We also need a better way to make the flu vaccine. The U.S. still relies on vaccines that are produced by growing the virus in chicken eggs, a decades-old method. This sometimes requires us to use a strain that doesn't match the circulating virus, because some strains just won't grow in eggs. So instead we manufacture a mediocre vaccine, rather than investing in new, modern technology that wouldn't need eggs and could produce more effective vaccines at lower cost. (Why are we stuck with old technology? It's a long story, but essentially it boils down to the fact that we rely completely on private companies to make the flu vaccine. The government doesn't make vaccines and has no plans to do so.)

With the right technology, we should be able to produce a universal flu vaccine, one that we can take once and never need again, like most other vaccines. Scientists are getting closer to that, with much help from the (currently shut down) NIH.

Meanwhile, we are looking at a particularly dangerous flu season, with few weapons to guard against it other than the not-very-good vaccine. (Aside: ineffective doesn't mean useless. Even if the vaccine is only 30% effective, as some estimates have it for this year, it's still a good idea. Everyone in my family got it.)

Oh, and one more thing: the flu shot cannot give you the flu. I only mention this because anti-vaxxers continue to promote this particular myth. 80% of people who have come down with the flu this year did not get vaccinated.

IOM to Public: Childhood Vaccine Schedule is Safe

Hey parents: if you've been taken in by anti-vaccine discussions on the internet, you might want to look at the newest report from the Institute of Medicine.  After a lengthy and thorough review of the evidence, the IOM issued a report last week that found that the current childhood immunization schedule in the United States is safe.

The IOM committee specifically looked for evidence that vaccination is linked to "autoimmune diseases, asthma, hypersensitivity, seizures, child developmental disorders, learning or developmental disorders, or attention deficit or disruptive disorders", including autism.  Their finding: no evidence suggests a link to any of these conditions.

The motivation for the report is the growing incidence of parents who worry that there are "too many, too soon" - a catchphrase that was the basis of an anti-vaccine campaign led by Generation Rescue and its spokesmodel, Jenny McCarthy.  This concern, which sounds reasonable on its face, never had any evidence to support it.

Anti-vaccine activists have pointed out, correctly, that the number of vaccines has increased significantly over the past several decades.  The current schedule has as many as 24 immunizations in a child's first two years, and up to five injections in a single visit.  The reason for this is simple: the scientific community has developed vaccines against a growing number of childhood illnesses.  As a result, many diseases that used to infect millions of children each year, killing or permanently injuring thousands of infants and toddlers, have almost disappeared from modern societies.  This is a good thing.

Many parents have been convinced to "slow down" vaccines after hearing advice from self-proclaimed vaccination authorities, such as "Dr. Bob" Sears.  Sears has published his own alternative vaccine schedule (which he apparently just made up - he certainly didn't do a scientific study) and whose has gotten rich selling his book and offering other advice.  Journalist Seth Mnookin calls Sears "a first-rate huckster."

Noted vaccine expert Paul Offit, in a peer-reviewed article in the journal Pediatrics four years ago, explained how Sears ignores all the science on vaccine safety, sometimes simply replacing objective evidence with his own "facts." Offit also called out Sears for his advising parents not to vaccinate their kids, but then not to tell their neighbors:

“I also warn [parents] not to share their fears with their neighbors, because if too many people avoid the MMR, we'll likely see the diseases increase significantly.” [wrote "Dr. Bob" Sears]  

In this astonishingly selfish comment, Sears admits that herd immunity works, but then says don't tell your neighbors, because then their kids might get sick and infect your unvaccinated kids.

Offit's article is a thorough, point-by-point rebuttal of Sears' numerous claims, many of them either misleading or downright false.  I highly recommend it.  Or  read the IOM's report online, for free.  Don't waste your money on Dr. Bob's book.

Let's hope all parents will follow the recommended vaccine schedule and ignore the voices of fear and unreason who are trying to scare them.  If you're still in doubt, read the heartbreaking story, from just a few days ago, of 7-year-old Alijah Williams in New Zealand.  Alijah's well-educated parents thought they were doing the right thing by withholding vaccines, after reading some scary material on the internet.  Alijah was infected with tetanus last year and fought it for months, nearly dying in the process.  His recovery will take 12 months, during which he will have to re-learn how to eat and walk on his own.  His parents have now become activists trying to spread the word among their community that infections are the real threat - not vaccines.