There is No Such Thing as the Super Flu

I beg you to stop nicknaming viruses

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Sometime around 2022, a particular variant of the Zero COVID movement emerged that loved to act as the minimizer police. If your resolve to wear respirators or measure indoor CO2 levels, or your commitment to COVID elimination wavered in any way, you would be declared a minimizer. I was declared a minimizer repeatedly, in large part because I objected to the Zero COVID insistence of their bespoke system of nomenclature that nicknamed emerging variants after mythical beasts to avoid confusing the public with PANGO lineage designations.

However, it was very confusing to the public to see media reports declaring “release the Kraken!” in regard to whatever newly evolved omicron derivative was evading antibody neutralization at that time. Since omicron emerged, new antibody-evasive variants are being regularly selected as the virus continues to circulate through immune populations. These variants are more capable of infecting people because they are less impacted by neutralizing antibody responses, but there has not been a single example of an emergent omicron variant that is substantially more pathogenic. These new variants can infect you, but they do not make you any more sick than garden-variety omicron, and that is further mitigated by up-to-date vaccination.

People reasonably assumed that announcing a mythological monster—watch out, here comes Charybdis and the Nemean lion!—meant that something even worse than prior variants was on the way. In reality, it was just another version of SARS-CoV-2, the expected result of evolution in response to population-wide immune pressure. After being criticized for fearmongering, the armchair taxonomists of Twitter began naming variants after astronomical things like stars and galaxies. But the hyperbolic nicknaming has continued.

Now that the US is entering its second consecutive bad flu season and cases are surging, my news feed has become infuriatingly cluttered with headlines about”super flu.” This is not a thing that exists, and even if it did, there are ways to make it less “super” (which it isn’t to begin with). Those ways do not include taking supplements that balance glutathione and metabolic redox, as that New York Post article suggests. Exaggerating the specific threat that a virus presents opens the door to selling unproven remedies with overstated claims of benefits, as well.

In reality, we know how to deal with any kind of seasonal flu, super or otherwise. Get an updated flu shot. Seek medical care early, since antivirals need to be started as soon as possible to work. Stay home when you are sick. Take other precautions, such as wearing respirators in crowded or public indoor spaces.

I’ll say it again, because it’s important: get an updated flu shot. It’s not too late.

It’s not “super flu,” it’s H3N2

Safety precaution number one: get a vaccine

The supposed “super flu” is an variant of the H3N2 subtype of influenza A virus that has evolved immune escape capabilities. Usually what this means is that mutations have altered the head of the hemagglutinin (H3 HA) protein so that antibodies raised by the vaccine don’t recognize it. HA is one of the two proteins on the surface of the virus particle, and it is the H3 in H3N2. It binds the receptor on a host cell, which allows the virus to get inside and cause an infection. Antibodies that bind the HA head block receptor binding, which neutralizes the ability to cause an infection. When a lot of hosts have neutralizing antibodies to HA, the only viruses that will be able to infect hosts are those that have evolved to escape antibody recognition, so they will inevitably emerge.

That is what is being called “super flu”: a variant of H3N2 called subclade K that has acquired mutations in HA that allow it to escape vaccine-induced antibody neutralization. These mutations make subclade K HA antigenically distinct from the vaccine H3N2 strain, meaning they are poorly matched. We don’t know what impact this will have on disease severity, but we do anticipate that this will decrease protection against getting influenza at all. Viruses that aren’t efficiently neutralized are more likely to infect people.

This doesn’t mean that the virus has acquired superorthomyxoviral properties. Just because it is more likely to infect a human host does not mean that it is likely to be more pathogenic than any other H3N2 subtype virus. Vaccination will further reduce disease severity, because that’s what flu vaccines reliably do. My colleagues at McMaster University here in Canada recently showed that vaccination substantially reduces disease severity even when the circulating and vaccine strains are mismatched.

“Super flu” isn’t so super against vaccines

Yes, we do. And if someone says otherwise, they are not an expert. If someone says “super flu,” they are not an expert either.

H3N2 subclade K may not be “super flu,” but it is not harmless. H3N2 is typically thought to be more pathogenic than the other circulating seasonal subtype, H1N1 descended from the 2009 pandemic. H3N2 causes more severe disease and usually has a higher hospitalization and mortality rate. This season, H3N2 subclade K is completely dominant, meaning it is driving the surge in cases in North America.

Many people have suggested that the vaccine mismatch has rendered it useless against H3N2 subclade K, so what is the point? In addition, flu shot uptake has been dismal in the US, hovering at around 43% in all adults. Public confidence in vaccination has generally been eviscerated by the relentless onslaught of medical disinformation coming from the Department of Health and Human Services (HHS) Secretary Robert F. Kennedy, Jr., National Institutes of Health (NIH) Director Jay Bhattacharya, Food and Drug Administration (FDA) Commissioner Marty Makary, Acting Centers for Disease Control and Prevention (CDC) Director Jim O’Neill, and Center for Medicare and Medicaid Services (CMS) Administrator Mehmet Oz have all made inaccurate or derogatory remarks about seasonal respiratory virus vaccination. They have all contributed to a higher burden of seasonal flu by discouraging vaccination. It is true that flu vaccines will not work against H3N2 subclade K if nobody takes them.

Flu immunity is incredibly complex. We are exposed to multiple flu viruses, including repeated infections throughout our lifetimes with the same seasonal subtypes. Imprinting can bias our immune responses, which are shaped in each of us by the unique combination of our genetics, the genes that we turn on or off in response to infection, the different viruses we are exposed to, and the vaccines that we receive. We retain some cross-reactive immunity within and across subtypes, so beginning at a very young age, we are never completely immune naive to seasonal influenza.

Boosting our existing memory immune responses to flu amplifies these cross-protective responses even when there is a vaccine mismatch. That demonstrably reduces disease severity. Even if you are infected with flu, updated vaccination will likely prevent you from getting severely ill and improve the speed and ease of recovery. It will help keep you out of the hospital. It will keep you alive.

H3N2 subclade K is not a “super flu” virus. It is an influenza A virus that is evolving as these viruses always have: it is adapting to selection pressures in its host. As they have for the last eighty years, flu vaccines offer partial protection even when they are not a perfect match. High vaccine uptake can save thousands of lives during a bad flu season. Don’t believe unsupported claims that a supplement that purportedly optimizes your metabolism can replace the many benefits offered by an imperfect but very effective vaccine.

Once again, it’s not too late. Get your flu shot if you haven’t already.