On January 8, a care home worker in Ontario, Canada tested positive for the coronavirus. In the next two weeks, 127 of the care home’s 129 residents fell sick and 32 died. Tests show the UK variant of the virus, which is known to be at least 40% more contagious, is the culprit.
The UK variant “501.Y.V1” caught the world’s attention only in December but has been spreading so fast that the US Centers for Disease Control and Prevention (CDC) expects it to be the main coronavirus variant in America by March.
In South Africa and Brazil, two other variants — called “501.Y.V2” and “501.Y.V3”, respectively — are also spreading fast. The South African variant has been shown to dodge antibodies in people who have recovered from Covid. Scientists fear vaccines might be less effective against it. The Brazilian variant also possibly re-infects people who have had Covid. It has devastated the city of Manaus that was believed to have achieved herd immunity last August.
The sudden emergence of three deadly variants at the end of 2020 raises the question, why now? For almost 10 months, the coronavirus spread across the world without changing too much. At least, not in a way that would change its behaviour. This allowed scientists to make vaccines in double-quick time. But if the virus starts mutating rapidly now, we might again find ourselves where we were last February.
All three fast-spreading variants have a common mutation that lets them attach strongly to human cells. The South African and Brazilian variants also have mutations that make it harder for antibodies in blood to recognise them.
Such mutations were of no use to the virus last summer when most of the world’s population was uninfected and had not developed immunity to it. It could spread without a hurdle. Things are different now. The virus is running out of easy targets in places like the US, UK, Brazil, South Africa and also India, where the number of new daily cases has fallen sharply since September, possibly due to growing immunity.
So, the virus needs to get better at infecting and evading. It’s not surprising that the stealthier variants have emerged in Covid hotspots. “A so-so spreader might no longer be able to find new hosts to infect, but variants with mutations that help them spread can still transmit, and can take off from there,” Andrew Joseph writes in Stat.
How A Virus Changes
But how does a virus pick up new tricks? Viruses are not very good at making exact copies of themselves. Each time they replicate — which is every few hours — there is a possibility that something might change. The more Covid cases there are, more the chances of mutation. Over time, mutations that are advantageous for the virus become more common.
Emma Hodcroft, an epidemiologist at the University of Bern, tells Der Spiegel that immunocompromised patients – those undergoing chemotherapy, for example – are an especially fertile ground for mutations as a Covid infection in such a patient can persist for months. “The virus has a really long time to figure out how to co-exist with the human immune system.” The UK variant is believed to have come from such a patient.
Vaccines Can Stop This
The three mutants are bad news but if the virus continues to spread fast, there will be many more, and “there’s no reason to believe that it won’t become more efficient over time,” Cillian De Gascun, director of the National Virus Reference Laboratory at University College Dublin, tells Der Spiegel.
That’s why vaccinating people fast has become important now. Slowing down the pandemic will mean less transmission, less replication and fewer mutations. “Stopping transmission blocks the opportunity for viral mutation; it’s the only thing that does. And the only means we have of standing in the way of the virus is vaccination,” Lawrence Wright says in The New Yorker.