- The UK coronavirus mutation isn’t more deadly than other SARS-CoV-2 strains and does not cause more severe cases of COVID-19.
- However, the B.1.1.7 mutation spreads more efficiently than other strains and can infect more people.
- Experts explain that the increase in COVID-19 transmissibility could lead to more deaths, even if the virus itself isn’t more deadly.
The UK reported nearly 56,000 COVID-19 cases on December 31st, a new pandemic record for the country. The previous record of more than 53,000 infections was only one day old at the time. The B.1.1.7 mutation that was announced to the world a few weeks ago is believed to be responsible for the soaring case numbers in a country that was already in a soft lockdown just a month earlier. The UK reached more than 33,000 daily cases in mid-November, and then it seemed to flatten the curve. That record was broken on December 17th, when more than 35,000 new cases were recorded. Since then, the number of cases has increased dramatically, just as UK prime minister Boris Johnson announced even more severe restrictions for parts of the country ahead of Christmas and New Year’s. The fact that the UK registered the highest number of COVID-19 cases on December 31st is also very telling, suggesting even higher figures might follow in the coming days and weeks. A spike in deaths may be seen in the coming weeks, as some of the patients who have been just diagnosed with the illness will not survive the infection.
Scientists already have plenty of good news about B.1.1.7. The mutated strain does not cause more severe COVID-19, so it’s not more deadly. One of the genetic changes also allows doctors to detect the new variant with a PCR test rather than more complex genetic sequencing. A recent study suggested that the new coronavirus strain likely can’t infect people who already had COVID-19, which is great news. That’s also an indication that vaccines will prevent severe COVID-19 after infection from the B.1.1.7 strain just like other strains. But despite all that, some scientists worry that the higher transmission rates of the UK mutation will likely still lead to more deaths in the near future.
The mutated virus is a ticking time bomb, reads the title of a piece in The Atlantic, explaining why the UK mutation is so dangerous. The article quotes a simple example that Adam Kucharski, a professor at the London School of Hygiene and Tropical Medicine, put forward on Twitter.
Why a SARS-CoV-2 variant that's 50% more transmissible would in general be a much bigger problem than a variant that's 50% more deadly. A short thread… 1/
— Adam Kucharski (@AdamJKucharski) December 28, 2020
Kucharski compared a 50% increase in virus lethality to a 50% increase in transmissibility. B.1.1.7 is estimated to be 70% more infectious than other strains, according to Johnson’s remarks. A first study of the strain said the mutation would be 56% more infectious. The mutated virus is thought to be more efficient at binding to cells, which could lead to an increase in viral load since the virus would enter more cells and multiply better than other strains.
Kucharski ran numbers with a virus reproduction rate of 1.1, a fatality risk of 0.8%, 10,000 active infections, and a six-day infection generation time. With those figures, you could expect 129 deaths in a month. If the fatality rate increases by 50%, the death figure goes to 193. If the transmissibility rate increases by 50%, the number of deaths would soar to 978 in just one month.
The experiment highlights the fact that a more infectious virus can be more deadly without inducing more severe illness. The virus would reach a much larger percentage of the population than other strains. A low fatality percentage applied to a much larger population of infected people would still mean more deaths.
The above is just an illustrative example, but the key message: an increase in something that grows exponentially (i.e. transmission) can have far more effect than the same proportional increase in something that just scales an outcome (i.e. severity). 5/5
— Adam Kucharski (@AdamJKucharski) December 28, 2020
Kucharski’s example also explains what happened to America compared to countries that implemented more effective restrictions. Because of the relatively lax restrictions and more people who ignore safety measures, the virus spread wildly in the US. The country has registered almost 20.5 million infections so far and more than 354,000 deaths. The fatality rate isn’t higher than in other countries — it’s just applied to a much higher caseload.
The B.1.1.7 strain could further complicate things in the US and other regions without swift action. Accelerated vaccination campaigns could help combat the increased transmissibility of the virus. But until enough vaccine supply is available, countries might consider further enforcing safety measures to reduce the risk of B.1.1.7 becoming dominant. The Atlantic argues that the world has already trained itself on how to deal with an infectious pathogen. The same principles apply to the UK coronavirus mutation:
We’ve had a year to learn—about the importance of early action, of acting decisively even in the face of uncertainty, of not confusing absence of evidence with evidence of absence. A year to learn to aim not for perfection in knowledge but for maximal impact even while considering the trade-offs. And most important, a year to learn to not wait when faced with threats with exponential dynamics but to act as early and as decisively as we can—and to adjust and tamper later, if warranted.
As for vaccinations, the US might want to adapt its strategy to mimic Canada and the UK. America currently holds in reserve half of available doses so that the people who received the first shot can receive the second jab in three or four weeks. Canada and the UK decided to use their entire available supply for the first dose, trusting that vaccine makers will supply the second dose in time for the second shot. The UK has also put a new protocol in place for the booster shot, advising people who get vaccinated to get the second injection between 4 and 12 weeks after the first one.
The Atlantic’s full piece is worth a read.
