Globally, as of 8 September 2021, there have been 221,648,869 confirmed cases of COVID-19, including 4,582,338 deaths, reported to the World Health Organisation (WHO). As of 6 September 2021, a total of 5,352,927,296 vaccine doses have been administered.

I find these figures both shocking and comforting.

Shocking, because nearly five million deaths from a new virus is clearly a tragedy, and besides I strongly suspect that this figure does not present the actual number of deaths, which I fear is even higher still.

Comforting, because it’s clear that the vaccination roll-out, though far from perfect and weighted towards wealthy nations, has been effective to some degree in helping to stem what had been a rising tide of hospitalisation for serious complications of the virus in many countries.

But we can’t afford to be complacent, and here in the UK the latest statistics show that the rate of infections, hospitalisations, and sadly deaths is once again on the rise as a result of the Delta variant, which is highly contagious and against which the vaccines are also sadly less effective.

The Delta variant first detected is incredibly concerning. It is striking unvaccinated populations in many countries and has proven capable of infecting a higher proportion of vaccinated people than its predecessors.

The WHO classifies Delta as a variant of concern, meaning it has been shown capable of increasing transmissibility, causing more severe disease or reducing the benefit of vaccines and treatments.

According to Shane Crotty, a virologist at the La Jolla Institute for Immunology in San Diego, Delta’s “superpower” is its transmissibility. Chinese researchers found that people infected with Delta carry 1,260 times more virus in their noses compared with the original version of the coronavirus.

Indeed, Some US research even suggests that the viral load in vaccinated individuals who become infected with Delta is on par with those who are unvaccinated.

While the original coronavirus took up to seven days to cause symptoms, Delta can cause symptoms two to three days faster, giving the immune system less time to respond and mount a defence.

However, there could be worse to come. Yes, scientists remain focused on Delta, now the dominant variant around the world, but are tracking others to see what may one day take its place.

Mu, the variant formerly known as B.1.621, was first identified in Colombia in January. On Aug. 30, the WHO designated it as a variant of interest due to several concerning mutations, and assigned a Greek letter name to it.

Mu carries key mutations, including E484K, N501Y and D614G, that have been linked with increased transmissibility and reduced immune protection.

While the current vaccines prevent severe disease and death, they do not block infection. The virus is still capable of replicating in the nose, even among vaccinated people, who can then transmit the disease through tiny, aerosolized droplets.

And the brutal fact remains that to defeat COVID-19 will likely require a new generation of vaccines that also block transmission. Until then, the world remains vulnerable to the rise of new, worrying, coronavirus variants.

Marcus Alcock,

Editor, Emerging Risks

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