49 Greek letters and chewing gum


What does RNA live to do? Make copies of itself. The coronavirus genome (the genes that make up the virus), is a twisted strand of nearly 30,000 letters of RNA. (The human genome is over three billion.)

When the virus finds a cell it likes, it injects it with a strand of RNA containing its entire genome. It uses the machinery inside the host cell to replicate its 30,000 sequenced letters, copying and copying and copying. With each new infection, in each new cell, inevitable copying errors occur (mix-ups in the letter sequences).

Most of these make SARS-CoV-2 a less effective virus. But some have the opposite effect, shaping the virus to more efficiently do the only thing that RNA really wants to do – make more copies of itself.

We call this evolution. It is how variants like Omicron (B.1.1.529) – the most recent variant of concern – are born.

On Nov. 9 in Botswana a sample of the Omicron letter sequence was collected, sequenced by South African researchers, and uploaded to a central site on Nov. 23. On Nov. 24, South Africa reported to the WHO. Omicron cases have now been identified in more than a dozen countries including Germany, the UK, China, Australia, Canada, the list growing as you read this.

Omicron is scary because it has a large number of mutations in its sequence for the spike protein, which is the major target of our vaccines and is the entry point for SARS-CoV-2 to access our cells.

Omicron appears to be highly transmissible. Data from South Africa show test positive rates from Gauteng province jumped from around one per cent to 30 pe cent last week. (About 25 per cent of the population is vaccinated.)

A traveler from South Africa to Hong Kong who tested negative before his flight Nov. 11 then tested positive while quarantining in a Hong Kong hotel on Nov. 13. Someone across the hallway then tested positive for the new variant. Both individuals had high viral loads. Of 539 travelers from South Africa to the Netherlands last Friday, they identified 61 cases.

Unvaccinated individuals are more likely to become sick when exposed, have a much higher viral load, and are far more likely to transmit to others. In this way, unvaccinated people pave the way for the virus to achieve its mission: making copies of itself, leading to more mutations.

Ponder this: There are countries in Africa with two per cent vaccination rates.

How effective are vaccines against Omicron variant? Tracing the RNA sequences of the variants of concern shows Omicron to be more similar to the original Alpha than to the Delta lineage. So far, among vaccinated people, there have been no serious cases.

Viruses don’t want to become so deadly they kill off their hosts. They mutate to increase the amount of their genetic code circulating.

Mild diseases like the common cold keep hosts alive to spread more virus. But the number of spike protein mutations in Omicron is significantly more than in the other variants, including mutations that allow more efficient cell entry (increasing transmissibility), show resistance to neutralizing antibodies and evasion of innate immunity (making previous infections and vaccines less effective protection).

And then there’s gum. A new experimental chewing gum could reduce the amount of coronavirus particles in saliva and help slow transmission, according to a study in the journal Molecular Therapy.

The gum contains a protein that “traps” virus particles, reducing the spread of virus-laden droplets when infected people are talking, breathing, or coughing. The viral load in the samples fell by more than 95 per cent, the researchers said. The gum feels and tastes like conventional gum and meets FDA requirements.