What is a variant, how is it formed and why is it harmful? | VTx
There is the delta variant, the lambda variant and even the delta-plus variant. Variants of COVID-19 are spreading in the United States and in many parts of the world.
A variant is a mutated version of a virus that is produced when the virus replicates – when it is transmitted.
But how exactly do variants form and why should we care?
Lisa M. Lee, associate vice president for scientific integrity and research compliance, and professor of public health at Virginia Tech, has some answers. Lee is an epidemiologist, bioethicist and ethics educator. For over 25 years, she worked in public health and ethics, including 14 years at the Centers for Disease Control and Prevention.
Q. How is a variant formed?
Lee: Variants develop when a virus is transmitted. Whenever it reproduces in a new host, a virus has the opportunity to mutate, to reproduce incorrectly. Most mutations are harmless, but sometimes the change will result in a stronger or more contagious version of a virus. And when that happens, it hurts us.
We have seen variants develop very quickly with SARS-CoV-2 [the virus that causes COVID-19]. This was a real concern for epidemiologists because it meant the virus could mutate quickly. We recognized that if we didn’t get this under control quickly, we were going to end up with more virulent strains that would spread faster or that our current vaccines wouldn’t work against.
Q. Why is the delta variant considered to be more contagious than the original COVID-19 virus?
Lee: The delta variant is estimated to be 60% more contagious. Studies have shown that with the delta variant there are a thousand times more virus particles in the nasal passages than with the original virus.
This means that there are a lot more virus particles that are expelled when we breathe. The recipient inhales a heavier viral load and is much more likely to be infected.
When the delta variant is transmitted, there are a lot more virus particles clinging to it, so it is more sticky. All viruses are different, but what makes the delta variant of concern is that it is more likely to attach and enter the cells of the recipient.
Q. How can we prevent these variants from forming and spreading?
Lee: The answer to reducing the development of variants is to stop transmitting the virus. If we intervene with the vaccine and reduce the likelihood of the virus remaining present, we can reduce the risk of dangerous variants developing.
The great promise of the vaccine was that we would stop transmitting the virus, which would reduce the development of variants. Because we haven’t achieved the vaccine coverage we need to stop transmission – at least 85 percent worldwide – we continue to see dangerous variants develop.
Therefore, even if someone thinks that they do not need a vaccine for themselves, everyone who can be vaccinated should be vaccinated. Unvaccinated people unintentionally serve as a reservoir that allows this virus to continue to be transmitted and, therefore, to continue to mutate.
Vaccination is of course to protect individuals, but more than that, vaccination is for all of us as a community. For anyone who cannot get the vaccine because they are under 12, and for anyone with other health conditions that make the vaccine less effective, this is who to get the vaccine for. If all the rest of us are vaccinated, we are helping to protect those in our community who cannot.
Q. Herd immunity occurs when the majority of a population has received a vaccine. How can collective immunity help stop the spread of variants?
Lee: Collective immunity is like a donut. People who cannot be vaccinated for various reasons are in the middle, and the donut around them are all people who have been vaccinated, providing a layer of protection against the virus.
When someone infected with the virus interacts with the donut – consider throwing in a dusting of candy – it cannot pass through the vaccinated donut and cannot infect vulnerable people inside the donut hole.
Because now we have these super-contagious variants, we’re going to need an even higher level of population immunization. The sooner we can do this, the sooner we will prevent transmission and stop these variants.
Q. If someone is infected with SARS-CoV-2, does they likely have the delta variant?
Lee: When the Delta variant was introduced in the United States in early May 2021, it started somewhere with a few transmissions. Then, because it is so much more contagious, it quickly began to outperform the original virus. In August, the delta variant became the dominant virus transmitted in most communities.
The way we know where the variants are is by doing public health surveillance, which is actually testing the samples that people give for diagnosis and typing them in a lab.
The CDC has a public health surveillance program that identifies variants and can tell us what proportion of variants are transmitted in the population. Currently, the delta variant accounts for nearly 95% of COVID-19 infections in the United States
Q. Will there be other variants to develop from COVID-19?
Lee: I am sure we will continue to see new variants as long as the virus continues to be transmitted. Until 85 percent of the world’s population is vaccinated, the virus will mutate and produce variants. This is the sad reality of viral replication. Our best hope of returning to something closer to pre-COVID life is the rapid vaccination of all communities.
– Written by Jenny Kincaid Boone