Where did Omicron come from? Researchers created a sort of family tree which shows how the Alpha, Beta and Delta variants branched off of the original Wuhan strain of the virus (B1.1).
The Omicron variant seemed to appear out of nowhere with 45 mutations to the spike proteins. It has mutations that are not found in all prior variants. It is on a completely different lineage of the tree with a long line of mysterious unknown development.
It was first identified in South Africa on November 24, 2021. It is believed to have diverged from the B1.1 line in mid 2020. Where has it been since then? Mutations to the virus normally happen at about 0.5 per month. Omicron had 45 mutations in the spike protein. Over 18 months when Omicron was hidden from view, it developed mutations 3,5 times faster than other variants.
So where was Omicron during these 18 months and why were the mutations happening so fast?
- It might have spread in a population with low levels of testing and not been found. This is unlikely.
- It might have developed in a person who was chronically infected. One theory was that it might have developed in someone with HIV.
- It might have developed mutations in a non-human host and then jumped back to humans. We don’t test animals for COVID, so could have gone undetected.
A pier reviewed paper out of China explored this third possibility. The likely culprit is mice. The mutations that developed were significantly different that those that developed in humans. The mutations that develop in mice are similar to the mutations that developed in Omicron. The mutations allow the virus to fit well into mice cell receptors.
The idea is that airborne Omicron jumped from a humans into mice, the virus developed mutations that allowed it to better infect mice, then the virus jumped back into humans. This would be an inter-species evolutionary trajectory of the outbreak. This could explain why this virus can cause so many breakthrough infections in humans. Thankfully the Omicron virus causes an increased infection in the airways and not as much infection in human lungs. This may result in milder cases of disease. It will spread wildly throughout humanity with hopefully less death while offering some increased immunity for anyone infected. It could be a blessing in disguise by acting like a vaccine for the unvaccinated.
However we need to vaccinate as many people as possible around the world to avoid future mutations. We can not “boost” out way out of the pandemic. We might not be as lucky next time around.