Do viruses adapt to antivirals in the same way bacteria adapt to antibiotics? If not, why?

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For some years now, there has been global concern about the creation of superbugs that are resistant to almost everything, particularly antibiotics. My question is whether something similar could happen with viruses. Do viruses adapt in a way that makes them similar to antibiotic-resistant bacteria, or does their rapid adaptation and transmission make them fundamentally different? I tried researching this topic through papers and interviews, but I couldn’t find a clear explanation.

In: Biology

6 Answers

Anonymous 0 Comments

Well, yes. Viruses mutate all the time, requiring us to develop new countermeasures. That’s why we have Flu A and Flu B and all of the different “strains” of COVID. That’s the viruses “adapting”.

Anonymous 0 Comments

Short answer: yes.

Living things mutate. Most of those mutations don’t do anything, and some of them are harmful, but occasionally some of them are helpful. When a virus reproduces inside a host cell, there is always a possibility of small errors occurring during that process which can lead to mutations. This means not all the daughter viruses are going to be identical, and some of them may be resistant to whatever drugs or treatments are being used to try and prevent the viral infection.

However, there is a major advantage that antiviral medications have over antibiotics: viruses can’t reproduce on their own, they need a host cell. Viruses don’t have the machinery to make more of themselves, instead they co-opt the machinery of your body. The machinery of your body doesn’t change very quickly though, which means that a pretty effective way to treat a severe viral infection is to target the machinery in your body that produces copies of the virus. Unfortunately, that machinery is something your body needs to survive, which means that this approach can have pretty substantial negative side effects. For instance, a common multi-spectrum anti-viral drug is called Remdesivir, which targets viral RNA polymerase to prevent the viral DNA analogue from being copied. Your body also has RNA polymerase though, which means you can experience some side-effects like liver inflammation.

Anonymous 0 Comments

Yes, viruses adapt to most treatments against them. HIV has had a lot of treatments that have worked in the past until the virus has mutated to tolerate them. Indeed, the standard treatment for HIV for a long time, HAART, was actually a combination therapies designed to throw a multitude of antivirals that work on different mechanisms with the idea that the virus shouldn’t be able to adapt to all the different attacks in short enough time to survive.

It’s not become a big thing for a few different reasons, but the big one is that Anti-virals aren’t as widely prescribed or used. This is mostly because they kind of suck and aren’t broadly effetive. Antibiotics typically offer broad protection for a variety of different bacteria, so they are prescribed far more frequently. Since the bacteria are exposed to the stress much more frequently, they’re much more likely to develop immunity.

Most anti-virals are far more specialized in which viruses they work against, so they are not used as generically, and viruses see them less frequently.

Anonymous 0 Comments

To a much lesser degree.

Bacteria have evolved ways to specifically rapidly adapt to the environment. They don’t just do it through rapid breeding and random natural selection – they can create “patches” to their genome (plasmids) and share them with the colony.

Viruses are in essense very big, but dumb molecules. Their evolution relies primarily on chance and large numbers, when “assembly errors” occurs as new virus particles are built.

Anonymous 0 Comments

I think you are on the right track here. Some viruses (like the flu for example) get spread so quickly that we can’t really create a fullproof vaccine for them. We do have flu shots obviously and those do help, but because the flu viruses spread so rapidly, they also tend to mutate rapidly, meaning that any vaccine we create for one variant quickly becomes obsolete (I don’t think obsolete is the right word here, I just can’t think of another. The vaccine still works against the variant it was created for, it just doesn’t work for future variants that have mutated significantly).

I do believe there is a fundamental difference when we are talking about super bugs in viruses vs bacterial infections however. The way we cure them/prevent them is different. Antibiotics do not work on viruses.
The reason we are moving towards having drug-resistant bacteria is largely because people are not using and not disposing of antibiotics properly.
To break it down rather simplistically, let’s say we have 100 bacteria in a culture. Due to random mutations during replication, 10 of these are slightly more resistant to antibiotics. They can still be killed, it just takes a larger dose (or a more prolonged dose). So let’s say the standard treatment to get rid of these is to take antibiotics for 10 days. 90 of the bacteria may be killed off in 5 days, but we take the pills for 10 days to make sure we kill off the remaining 10 that are more resistant.
If used correctly, this works just fine.
However, in many cases patients will take the antibiotics for 5 days, realize that they feel better (because 90% of their infection is gone), and then will stop taking them. But, now that there are no longer antibiotics in the system, the 10 bacteria that were more resistant have time to reproduce. And the replicants that they have all now share that higher resistance.
So do this cycle multiple times where you now have a more resistant bacterial infection where you need to have a full 10-day dose to kill off 90% of the bacteria and maybe you will need another 5 days to kill off the remaining 10% that have more mutations that make them even more resistant.
Thus doing this multiple times across a population essentially kills off the weaker bacteria while leaving the stronger ones to reproduce. And with each cycle of this the bacteria gets more and more resistant until the point where we aren’t able to administer a high enough dose to get rid of it. (Remember that antibiotics don’t just affect the bad bacteria, they also get rid of the bacteria that you need. So too high of a dose is not good for you).

Back to viruses, I don’t believe the exact situation would occur, however it may be similar. Say we have a vaccine for flu A. Flu A transmits quickly and mutates quickly. So when people get the vaccine it helps to prevent them from getting flu A, however as it mutates the vaccine quickly becomes ineffective.
I guess it wouldn’t necessarily be considered vaccine-resistant so much as we would continually have to create newer vaccines to counteract the mutations.

However, since not all viruses mutate that quickly, there is a similarity. Take smallpox for example. Due to huge vaccine efforts across the globe, smallpox has been eradicated. But, what if we weren’t able to get 100% of it? In that instance, the remaining virus could still mutate and then spread to the rest of the world now that it’s no longer resistant to the vaccine.

Sorry I think I am rambling a lot with this post… I will try and clean it up when I can. But tldr, bacterial super bugs and viral super bugs are not the same thing, however there are situations in which a virus can mutate to the point that it is no longer susceptible to our current vaccines. The similarity for how both situations occur is that if only a subset of the virus/bacteria is killed off? Then that leaves room for the remaining ones to replicate and mutate further.

Anonymous 0 Comments

Also, this isn’t a response to your question, I just want to put a PSA here for anyone who may be reading this thread.
A large reason why we are seeing more and more drug resistant bacteria is because antibiotics are improperly disposed of and once they are in the water supply and stuff have a diluted effect and kill of only the weakest of the bacteria, leaving the stronger ones to mutate.

If you need to dispose of any medications, take them to your local pharmacy and they should be able to send them off to be disposed of in a safe way.