As we entered spring 2021, the Alpha variant of the coronavirus had become the dominant variant worldwide. However, the emergence of the Delta variant, a more transmissible strain, was on the horizon. The question arose: what happens when two variants clash?
Let’s consider a hypothetical scenario where both variants reach an isolated city of 1 million people, all susceptible to both viruses, on the same day. When a person is infected with Alpha, they transmit it to an average of 5 close contacts, then begin to feel sick and immediately isolate themselves. The same process occurs with Delta, except that an infected person transmits it to an average of 7.5 close contacts.
After six days, Alpha will have infected 15,625 people. In contrast, Delta will have infected more than 10 times as many. Just 20 hours later, Delta will have infected the rest of the population, all before Alpha could infect 6% of it. With no one left to infect, Alpha dies out. This model, while drastically simplified, accurately reflects the real-life scenario where Delta drove Alpha toward extinction in a matter of weeks.
Viruses are wildly successful organisms. There are about 100 million times as many virus particles on Earth as there are stars in the observable universe. Even so, viruses can and do go extinct. There are three main ways that this can happen.
Firstly, a virus could run out of hosts. This might have happened in early 2020 to a flu lineage known as B/Yamagata. When much of the world shut down, social distanced, and wore masks to slow the spread of COVID-19, that dramatically reduced the number of hosts available for B/Yamagata to infect.
Secondly, a virus could go extinct if it kills all its hosts. This almost happened back in 1950s Australia when scientists released a virus called myxoma to control the population of the invasive European rabbit. The virus evolved to be less deadly, allowing both the virus and the rabbit population to survive.
The third way a virus can go extinct is if it’s outcompeted by another virus or strain, like we saw earlier with Delta and Alpha. However, viruses don’t always compete with each other. A viral species can carve out its own distinct niche, allowing multiple viruses to co-exist.
So, will SARS-CoV-2—the species of virus that causes COVID-19—ever go extinct? Variants within the species will continue to arise. Those variants might drive prior ones to extinction, or not. Regardless of how the variants compete, the species itself is pretty firmly established among humans.
If we managed to vaccinate enough people, could we drive SARS-CoV-2 to extinction? Our vaccination campaign against smallpox worked because the vaccine was highly protective against infection and smallpox had no close animal reservoir in which it could hide. But SARS-CoV-2 can hide out in animals, and our current vaccines, while they provide excellent protection against severe illness and death, don’t prevent all infections.
So, conceivably there are two ways that SARS-CoV-2—the entire species—could go extinct: a cataclysmic disaster could kill us all, or we could invent a universal vaccine that prevents all SARS-CoV-2 infections, those caused by all the variants that currently exist and those that don’t. Let’s work toward that second option.
Create a simulation to model the spread of the Alpha and Delta variants in a controlled environment. Use graph paper or a digital tool to represent the population. Assign different transmission rates to each variant and track the spread over several days. Discuss how the differences in transmission rates affect the outcome.
Organize a class debate on the topic: “Can SARS-CoV-2 ever go extinct?” Divide the class into two groups, one arguing for the possibility of extinction and the other against it. Use evidence from the article to support your arguments. This will help you understand the complexities of viral extinction.
Research and present a project on a virus that has gone extinct or nearly extinct. Include information on how it happened, the impact on the population, and any measures taken to prevent its spread. Compare your findings with the scenarios described in the article.
Design an infographic that explains the three main ways viruses can go extinct, as described in the article. Use visuals and concise text to make the information engaging and easy to understand. Share your infographic with the class and discuss its key points.
Write a reflective essay on the potential future of SARS-CoV-2. Consider the factors that could lead to its extinction or continued existence. Reflect on the role of vaccination, public health measures, and scientific advancements in shaping this future. Use information from the article to support your reflections.
alpha – the first letter of the Greek alphabet – The word “alphabet” is derived from the first two letters of the Greek alphabet, alpha and beta.
delta – the fourth letter of the Greek alphabet – The symbol for delta in mathematics is often used to represent a change in quantity or variable.
variants – different forms or versions of something – The new software update includes several variants of the user interface to cater to different preferences.
coronavirus – a type of virus that causes respiratory illnesses, such as COVID-19 – The coronavirus pandemic has affected millions of people worldwide.
transmissible – capable of being transmitted or spread to others – The flu is a highly transmissible illness that can easily spread from person to person.
infected – contaminated with a disease-causing agent or pathogen – The doctor confirmed that the patient was infected with the flu virus.
population – the total number of people or organisms in a particular area – The population of the city has been steadily increasing over the past decade.
extinct – no longer in existence – The dodo bird is an example of a species that is now extinct.
viruses – infectious agents that can only replicate inside the cells of living organisms – The computer was infected with a virus, causing it to crash repeatedly.
species – a group of organisms that share common characteristics and can interbreed to produce fertile offspring – The Amazon rainforest is home to a diverse range of plant and animal species.
