Thought of the Day - December 23 - Viral Mutation

As we have talked about it before - viruses mutate all the time ( Thought of the Day - June 26 -Worrying Signs Concerning Immunity ) but the issue is whether a mutation results in a different strain, and if this strain has different characteristics, and finally if these characteristics affect transmissibility, immunity response, and lethality.

While we have heard there have been a number of new strains of SARS-CoV-2, up until now none have really had significant effects in transmissibility (the rate of spread), immunity response (affecting herd immunity) or lethality (the likelihood of causing complications leading to chronic issues or death). It seems this may have changed with the UK strain (N501Y.V1) that although identified way back in September (about the same time as the Denmark mink-strain - H69/V70 deletion) is starting to prove to have higher transmissibility and thus is becoming the dominant strain in the south of England; note there is no evidence so far that the new strain causes a more severe or deadly disease.

According to the WHO, people who catch the new variant infect 1.5 other people on average, compared to a rate of 1.1 for previously known variants in Britain (i.e. is about 70% more transmissible). A report on the preliminary genomic characterization of the UK strain suggest this is true as the virus has “an unusually large number of genetic changes, particularly in the spike protein.” Thus the scramble this week to curtail travel in and out of the UK.

This clamp-down is also affecting commerce. English fishing boats are forced to remain in port. Britain’s biggest port stopped all traffic heading to Europe. Germany is even banning cargo planes to and from the UK. British suppliers are sounding the alarm as trade-routes are now hobbled thus food supplies into the nation could face major disruption. This comes on top of the planned total lockdown that the UK will be implementing on December 26th.

Unfortunately, this action will probably prove to be a case of barn-door slamming. Genomic sequencing of the virus has shown the UK strain has already spread to other countries - across Europe and as far away as Australia. Health Canada said Sunday there have been no recorded cases of the new strain here, yet.

In addition, there is another similar but distinct new lineage that has been spreading in South Africa (N501Y.V2). Here also they are also experiencing high rates of transmission.

Up until now we have been lucky. Following the first strain identified in Wuhan (L), there has been the G (D614G) mutation that emerged in Europe in February and became globally dominant, then the V (A222V) strain that spread across Europe in the summer (please note the nomenclature is different across authorities and also changes with stage of analysis) - none of which proved to be very significant different. Fingers crossed that in the coming months none of these new strains will be renamed to SARS-CoV-3 (a significantly genetically-different virus) or be shown to cause COVID-20 (a new variant of infection).

Cheers

Cliff