Don’t Worry About Mu. Don’t Worry About Boosters. Worry About This.
Covid news never stops coming, and it won’t stop coming until people stop getting Covid. Current talk is about boosters to deal with falling antibody levels in the vaccinated, and Mu. Mu is the latest in a mysterious parade of greek letters going through the media: a (newish) variant of SARS-CoV-2 spreading around the world.
Will Mu kill you? Do you need a booster if you’re fully vaccinated?
Probably not on both counts. What is more likely to kill you than Mu, or Delta, or a lack of a third shot, is letting the virus continue to evolve. Right now, SARS-CoV-2, the virus that causes Covid-19, is running around the world and mutating in the naive bodies of the unvaccinated, making new variants, infecting new people, changing and growing.
When unvaccinated and infected people mixing with vaccinated people and each other, we encourage the virus to evolve into ever more dangerous forms.
How Evolution Could Make Everything Even Worse
When any SARS-CoV-2 virus gets into a body, it will try to reproduce, and it will succeed as long as it can get into a cell and make the cell build more virions (the individual viral particle). This means only the most successful viruses get to keep reproducing: the fastest, the most efficient at building more virions in the cell, and the least likely to be fought off by the body’s immune system. This process of natural selection is fast for a virus, giving it a chance to try new and dangerous (for us) things. This is how we got variants that are a bit harder for our bodies to fight off, like Beta and the newer Mu. It’s also how we got super reproducing fast viruses, like Alpha and the global horror show we call Delta.
Could a future variant combine features of immune escape with something like Delta’s infectivity?
Maybe! Let’s not find out!
How Do We Stop It?
The only way to keep a virus from evolving is to keep it out of the cells it needs to infect in order to reproduce. The first way to do this (and my personal favorite) is keeping it out of the body altogether. No cells, no evolving. This is what masking and hand hygiene accomplish. Also, not doing things like going to crowded concerts — to pick a couple at random — maybe skip Megadeth, or The Killers, who are both currently touring during a global pandemic.
The second way is to kill all the viruses while they’re infecting cells. That works, but it’s hard to kill them all, especially if you’re not vaccinated, you immune system isn’t responding well, or both. The faster the body responds and fights the infection, the less chances the virus gets to evolve. This is why it can’t do as much in a vaccinated person. But inside of an immunocompromised person? It can work for months to come up with new variants, and that person can often spread them around for the entire time they are infected. But anyone who gets the virus can generate a new, more powerful variant and potentially pass it along. It’s like playing the world’s worst lotto.
The problem is leaving most of the world unvaccinated, not only to get sick, but as billions of laboratories for the virus to experiment with making itself better at attacking whomever it comes in contact with. Even if you were the most selfish bastard in the world, you should not want this. As one of my readers I know you’re not selfish, you are a moral exemplar who wants to see no part of the world left uncared-for in this pandemic, as well as good looking, funny, and intelligent. But if you were selfish you should desperately want everyone in the developing world vaccinated as soon as possible.
When a highly infective version of the virus has many unvaccinated victims to work with, but those victims are mixing with vaccinated people, the virus is getting millions of little tries at overcoming existing immunity.
Will a New Strain Beat Our Vaccines?
We don’t know the practical range of this SARS virus’ ability to mutate. It could be at its worst possible form right now. But it probably isn’t.
Some virologists think Delta might be at the end of this coronavirus’ bag of tricks in terms of mutating into being more infectious. After all, there’s only so many changes a coronavirus can make before it doesn’t work as a virus anymore. Maybe Delta is its most infectious form… but many knowledgable people thought that of Alpha, which Delta has driven to near-extinction.
Right now Delta, like Alpha before it, doesn’t have strong evolutionary pressure to pick up the immune escape in terms of finding new hosts among the unvaccinated: it’s doing just fine, thank you. But a slow enough global vaccination process (over years) could select for a version of this virus that has both profound immune escape (an unrecognizable spike protein) and Delta-like transmissibility. That could reach the WHO’s top level of variant classification: a Variant of High Consequence. In the immortal words of Dr. Egon Spengler:
It would be bad.
Vaccination and immune responses are not binary things. Immunity isn’t on or off, it’s a series of actions your body takes in an ongoing process. It involves the antibodies that are so often in the news, but they are only one part. There’s also other cell types, like T and B cells, that are even more important in long term immunity for stopping the virus from reproducing. All of this to say: “immune” is a complicated state.
If vaccinated (or recovered) people are exposed to the virus often enough, evolution gives that virus a reason to get better and better at evading the immunity from vaccination. If it infects enough unvaccinated bodies, it has a laboratory for doing just that.
The more differently shaped any disease-causing virus is from the one your body knows, the less quickly your body reacts to it, the more likely it is to cause disease. That’s what Mu may have — a different shape. But it’s nowhere near as good at making copies of itself as Delta is, so Delta wins.
So, is Mu a problem? For any single individual, not especially. But agencies like WHO and CDC are looking at large aggregate effects. Mu has mutations that likely make it harder for vaccinated or recovered people to destroy as quickly or efficiently as other variants. It has also spread during a time when Delta was pushing almost everything else out of circulation. But Mu simply doesn’t have Delta’s transmissibility.
Can a virus, in general, get much more transmissible than Delta? Yes. The diseases we think of as childhood diseases are all much more transmissible. That’s what makes them childhood diseases — they’re so transmissible you just get them because you were born. But can a coronavirus get more transmissible than Delta? We don’t know for sure, but probably not much. There is a limit to the coronavirus’ range of realistic mutations, even if we don’t know exactly what that limit is.
It’s not easy for a virus to completely escape our immune systems, which have evolved for millions of years just to kill the tiny fuckers as fast as possible. But it’s possible, after all: humans keep having pandemics. What would drive a variant into having just the right characteristics of infectivity and immune escape to set the effort to fight the pandemic back? A partially vaccinated global population is perfect — just enough people vaccinated to make evolutionary pressure point the virus towards immune escape, while getting so many tries at evolving by keeping the amazing transmissibility of Delta.
But over time, does that guide the virus into a form that wins by infecting the previously resistant? I don’t know. No one knows. Let’s not find out! The only way to not find out is to deny the virus all of its laboratories: that means social distancing forever, or vaccinating all the human beings on Earth we can as fast as possible. Not boosters, which only make sense for the immunocompromised, but vaccinating everyone everywhere before the vaccines start losing their effectiveness.
Deny the virus its evolutionary laboratory, and deny it the chance to evolve past our immunity. Don’t worry about Mu, boosters, freedom, or fish bowl cleaners and dewormers.
Worry about getting vaccines to west Africans, to Southeast Asian elders, to teenagers in Brazil. Worry about patents and pharma policies that are preventing global vaccination. Worry about short-sighted US and European plans to buy up (and ultimately waste) millions of doses out of the baffling belief that Covid respects borders. Worry about supporting manufacturing in regions without the money and infrastructure to buy doses from major pharma companies. Worry about getting a TRIPS waiver for vaccines, along with mandates to share manufacturing know how and access to manufacturing materials. Until everyone who wants a shot has had one, not even vaccine misinformation is as dangerous as just not vaccinating everyone we can.
Worry about getting this damn thing over with.
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