In 2020, SARS-CoV-2, the virus that causes COVID-19, changed the world.
Illustration of coronaviruses displaying statistics: Over 100 million cases; over 2 million deaths; multiple lockdowns; millions unemployed
Cartoon-style illustration of a coronavirus, with “hands“ on its hips. Above it, the text: “As it spread like wildfire around the globe, the virus changed, too.“
Cartoon-style image of viruses infecting a host. Text: Each time SARS-CoV-2 enters a new host, it can make millions of copies of itself — and during this process typos, or mutations, can occur in its 30,000-letter genome
Text: These mutations occur largely at random, but those that help the virus survive and reproduce are more likely to persist. Scientists are closely monitoring those mutations for ones that could make the virus more dangerous.
Illustration of scientists in front of a computer screen examining a phylogenetic tree. Text: Scientists have analyzed more than 565,942 viral genomes from more than 140 countries. These analyses have revealed that the virus accumulates about two new mutations each month.
Animated conceptual illustration of the protein correcting errors during replication. Text: One reason for this relatively low mutation rate may be that coronaviruses have a proofreading enzyme that catches and corrects errors as the virus replicates. The influenza virus, which lacks the proofreading enzyme, mutates about twice as often.
Text: Many of the mutations in SARS-CoV-2 have occurred as a result of its battles with the immune systems of its human hosts.
Top left: An illustration of scientist Lucy van Dorp. Bottom right: Comic illustration of a bruised and battered coronavirus, stabbed with a sword. Word bubble coming from scientist's mouth: “You can think of these as the battle scars in the viral genome from where it’s been interacting with our own immune proteins.” – Lucy van Dorp, University College London
Animated illustration of.a protein switching out U and C in a string of DNA. Text at the top: Scientists know this because one of the body’s antiviral proteins causes a specific kind of mutation, where cytosine (C) has been replaced with uracil (U). This C to U switch is the commonest mutation in the genome, making up around 40 to 50 percent of the viruses’ mutations.
Illustration of coronavirus, with a zoom in on the squiggly brown and green protein. Text: The vast majority of mutations have little or no effect on how the virus behaves. However, scientists keep a particularly watchful eye out for mutations in one critical region of the genome: the gene encoding the spike protein.
Illustration of spike proteins providing “helping hands“ to connect the virus to a cell. Text: SARS-CoV-2 uses the spike protein to attach to our cells, so mutations here could influence how the virus enters human cells, and which cells it is able to infect.
Upper Right: Illustration of a coronavirus covered in a yellow much. Lower left: a cell is making a “yuck“ look. Text: The spike protein is also a main target for many COVID-19 vaccines and treatments, so mutations here could affect how well these therapeutics work.
Illustration: The United Kingdom on a map. Text: In December, scientists identified a new strain of the virus, dubbed B.1.1.7, that was spreading rapidly in the southeast region of England.
Comic-style illustration of Boris Johnson at a podium. Caption at the top: The discovery led officials in the United Kingdom to tighten restrictions and governments in other parts of Europe to ban travel from the country.
Illustration: An irate looking Englishman in front of a cow. Caption at the top: The fact that B.1.1.7 was spreading doesn’t necessarily mean the virus itself had become more transmissible.
Gif of a bar, filled with people smiling and laughing with their mouths wide open, and happy-looking Covid viruses filling the air. Caption at top: The strain could have just got lucky — for example, by emerging in a place where transmission was more likely to happen.
Comic illustration of a coronavirus sipping on some orange juice. Caption: It now looks like B.1.1.7 is indeed better able to spread between people — but more research is needed to pin down how, exactly, the mutations have changed the virus’s biology.
Illustration: A cartoon N501Y strain coronavirus with an especially strong “arm“ (spike protein) shaking hands with a cell. Caption: This new strain is particularly alarming because it quickly acquired so many mutations — 17, some of them previously known — that alter the virus’s proteins and thus, potentially, its behavior. One change makes the spike protein bind more strongly to host cells.
Illustration: A cartoon 69-70 deletion strain coronavirus with disguise glasses & mustache shaking hands with a cell. Caption: Another change may help the virus avoid detection by antibodies.
Illustration of South Africa on a map. Caption: Other mutations have also caught scientists’ attention, including a variant first identified in South Africa dubbed 501Y.V2.
Illustration of a D614 coronavirus with a sweatband on its head running a marathon (leaving other coronaviruses in the dust. Caption: D614G, a mutation that first appeared in China last January, has been a subject of intense research due to its rapid spread.
Text: Several lines of evidence support the notion that D614G made the coronavirus more transmissible.
Illustration of a nervous-looking woman with a SARS-CoV-2 peeking out of her open mouth. Text: Experiments in human respiratory tract cells show that the D614G strain more readily infects cells
Comic-style illustration of a blue-hatted hamster sitting in front of a giant tissue box and checking its temperature. Another hamster blows its nose behind him. Text: Studies in hamsters show that those infected with D614G spread the virus more rapidly
Illustration of two graph lines: the top one is red, full of successful and angry looking coronavirus. The bottom is blue, with more muted looking viruses. Text: Epidemiological work from the UK suggests outbreaks grew faster when seeded by viruses carrying the D614G mutation
Comic-style illustration: Virus phylogeny with points showing repeated emergence of similar mutations. Text: Some scientists are skeptical that D614G strain has made much difference to the pandemic. That’s because mutations that give the virus an evolutionary advantage should be more likely to turn up repeatedly in the virus’s family tree.
Illustration of Lucy Van Dorp speaking. Text at top: But this doesn’t appear to be true for D614G, according to work led by Lucy Van Dorp at University College London. Words in speech bubble: “I think it would be a mistake to think that this mutation has radically changed the virus. I personally feel that the effect is very subtle at best.” – van Dorp
Text: There has also been a lot of concern about the spread of SARS-CoV-2 among mink farms.
Comic-style illustration of a sick mink. Caption at top: Viruses in mink had mutations in the spike protein.
Comic-style illustration of a mink coughing on a human. Red letters spell out KOFF above the mink's head. Caption at the top: Mink can transmit the virus back to people.
Comic style illustration: A gathering of sick mink. Caption at the top: Mink farms were becoming hotspots for outbreaks in the animals
Comic-style illustration of type scientists peering through a window, staring at a coronavirus drinking beer at a bar. Text at top: Scientists have not yet found convincing evidence that any of the mutations within mink change how the virus affects people, but researchers continue to monitor these mutations closely, just in case.
Comic-style illustration: Coronaviruses going through a metal detector. One holds a knife behind its back, is sweating and whistling innocently. Text at top: So far, there is not yet definitive evidence that any of the mutations that have emerged in SARS-CoV-2 have made the virus more virulent — that is, more able to cause severe symptoms or death.
Comic-stye illustration of viruses “mining“ inside of a sick human's body. Caption: Some scientists think that, in general, viruses evolve to become less lethal, since killing off a host too quickly will make it more difficult for it to replicate and spread. There’s little evidence for that notion, though — or for the opposite, that viruses become more harmful over time.
Comic0style illustration of an elderly coronavirus, sitting cozy in an easy chair with its feet on a “skull“ footrest. It reads a paper. There are various Viking-style weapons on the wall behind it. Caption: According to one theory, however, OC43 — one of the coronaviruses behind the common cold in humans — started off as a pandemic virus in the 1889, but became less lethal over time.
Comic-style illustration of a giant vaccine pointed at a scared coronavirus. Two other coronaviruses run away in the background. Caption: As we get better at battling SARS-CoV-2, the virus will face increased pressure to evolve new ways to survive.
Comic-style illustration of three large figures -- labelled “WHO“ “CDC“ and “NHS“ peering over a sweating coronavirus. Caption: We can only wait and see how SARS-CoV-2 will continue to evolve in people. What we do know for sure is that the coronavirus will keep changing — and as it does, scientists worldwide will be watching.

This piece was produced in cooperation with the Nib

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