How Not Getting Vaccinated Contributes To New Disease Variants
As vaccination rates stagnate, new variants of the virus that causes COVID-19 are emerging and becoming more common. This is concerning to public health officials like State Health Officer Dr. Alexia Harrist, who sat down with Wyoming Public Radio's Ivy Engel to discuss viral mutations and why an unvaccinated population is still a threat to those who are vaccinated.
Dr. Alexia Harrist: So a mutation is essentially an error in the virus's genetic code that is created as the virus replicates or makes more of itself. Viruses are really just essentially genetic material surrounded by a coat of proteins, and they can't replicate on their own. That's why they infect us - because they need our cellular machinery to be able to replicate. So they infect us, they get into our cells, and our cells essentially produce more virus. During this process, errors are introduced into that viral genetic code, the virus is replicating many, many, many times in our bodies. When we get infected, many of those errors don't really cause any changes at all in the virus. Some of the errors actually make the virus weaker, and less able to infect us. But some of the errors, and these are the ones we're really worried about, actually make the virus stronger, they make the virus more able to infect us and cause illness. And those errors are the mutations that we talk about. Once the virus has an error that makes it stronger, that particular virus has an advantage over the other ones, and that virus is going to replicate more, and eventually become the predominant virus that exists.
Ivy Engel: Are there certain things that make mutations more likely to happen?
AH: Really, it's just the amount of replication that's going on. So the more replication that's going on, the more areas are going to be introduced, and the more likely it is and the faster we'll get an error that makes the virus stronger. And so that's why immunization rates are linked to the development of variants like we're seeing in COVID. The more people that there are where the virus is spreading, the more the virus is replicating, and the greater chance we have of seeing some of these variants emerge, that can be very dangerous. The more people who are vaccinated, the less chance that that virus gets to replicate, the less likely and the slower it will be that we'll see dangerous variance.
IE: I've heard a lot of people say that COVID seems very susceptible to mutation. Is it susceptible to mutation more or less than other viruses?
AH: So a lot of it depends on the characteristics of the virus, how much the virus replicates in our bodies, but COVID is a type of Coronavirus, and Coronaviruses, the genetic material they contain are RNA, and those RNA viruses do tend to have more errors in the replication process and develop more variants than some of the other types of viruses.
IE: You touched on this a little bit, but how does an unvaccinated population threaten a vaccinated one?
AH: In the context of variants, if the virus has a chance to replicate, then it also has a chance to develop these mutations that make it stronger and develop variants that can more easily infect us, that can potentially cause us to be sicker, or that can have resistance to some of the treatments and the vaccines that we have. So having a lot of unvaccinated people gives that virus more of a chance to replicate it and more of a chance for those errors, and those stronger variants to develop. The big concern is that we develop a variant that is resistant to our treatments, that is resistant to the vaccines we currently have. And then those people who have been vaccinated may be no longer protected if we get one of these variants that are not susceptible to the vaccines. I'll also point out that even outside of the context of variants, that not everybody can be vaccinated. And so, we know that children under 12, currently can't be vaccinated. We know that there are people with conditions, such as cancer or other conditions that impact their immune systems. That means that they're not going to be able to build an immune response to the vaccine. And so the more of us that get vaccinated that can, the more we're able to shield those other people that can't get vaccinated or whose immune systems aren't going to be able to produce a response, the more we protect them from infection.
IE: Why don't vaccines always protect against all variants of a virus?
AH: Vaccines are essentially designed based on the virus that they're supposed to protect against. And so, they're designed for COVID, specifically on a piece of the virus, it's called the spike protein. And that protein is how the virus enters our cells and infects us. And so if there are changes to that spike protein, because of mutations that essentially make the spike protein look different than what we created the vaccine for, that is when the vaccines will no longer protect. The vaccines help us make antibodies against that protein, and if that protein changes so much that our antibodies don't recognize it, that is when a vaccine might not help us against a variant.
IE: I know that immunity can be built from either being naturally infected or from a vaccine. Is there a difference in immunity protection from either of those or are they kind of similar?
AH: It again varies for different types of infections. What we're seeing in COVID is that the vaccines are producing a very robust, and from what we know so far, long-lasting, immune response and protection. What we've known from studying COVID over the past year and a half is that people, if they do get naturally infected, they do develop an immune response, but that immune response can fade and we're still understanding the specific timeframe. But right now, we're concerned about reinfection beginning at about three months after the initial infection.
IE: Is there a difference in immunity to the Delta variant from natural infection or vaccination?
AH: So what we've seen from studies of the vaccines, including the three vaccines that we have in the United States, is that the vaccines do provide protection against the Delta variant. And especially, and this is really true for all variants, provide protection against severe infection and the need for hospitalization. Natural immunity we don't know as much about, but we certainly [are] concerned because this virus has changed from the virus that people might have been infected with earlier that there could be reinfection. And we have certainly seen reinfection among people with these new variants that have emerged over past month.
IE: Okay. Well, I think that that has hit all of my questions. Do you have anything else that you want to add?
AH: Yeah, I think I would just add, what are we concerned about with these variants. CDC has classified certain variants as variants of concern. We have seen all of them here in Wyoming, although some more than others. And there are several reasons why they can be concerning. The first is that they can be more infectious than other strains of the virus. That is specifically true for the Delta variant. The Delta variant is more infectious than the Alpha variant, which was more infectious than the original strains that were circulating. So the Delta variant is very, very infectious, which means that people can spread it more easily to other people. Another factor that we look at is does the virus cause more severe disease, and there is some evidence at that time that the Delta variant may cause people to become more sick than some of the other strains. And then really, the third thing we're concerned about with these variants is, do they impact the ability of our vaccines and our treatments to work. And some of the variants that we have here in Wyoming do seem to make some of our therapies, the medicines that we use to treat people who have COVID-19, less effective. So that's why we're so concerned about these variants. And these mutations, we really come a long way in our understanding of COVID. And the tools we have to fight COVID. And we don't want these variants to essentially erase that progress and put us back at the beginning where we don't have a vaccine or don't have therapies to combat it.