The Myth of Milder Covid
There's a myth that viruses become less deadly over time, the more they mutate. This is unfortunately wishful thinking and shows a complete lack of understanding of Darwinian evolution.
Given any two competing mutations of a virus, there are a number of key factors in which one will become dominant.
One is the speed of spread. If that is the main significant factor, as with the Delta, it will move through a community faster than the original Covid virus, and therefore infect people before the original virus has spread to them.
But another is almost certainly vaccine evasion. If we have two variants, and one is better at evading the vaccine triggered immune response, then it will have a better chance of spreading among the vaccinated community, especially as vaccine protection wanes over time. It will make inroads into a population largely protected by vaccines.
If we have both fast transmission and increased vaccine evasion, that mutation would make inroads into the population where earlier variants did not. This is what we may have with the Omicron variant.
But there is no evolutionary law which says that faster transmission and increased vaccine evasion are linked to a milder strain of the virus. Only a milder strain which was both fast transmitting and very vaccine evasive would drive out other mutations, and there is no sign this is the case. As Covid mutations are random, this could happen, but the fact that mutations are random means that it will not be bound to happen.
There's a myth that viruses become less deadly over time, the more they mutate. This is unfortunately wishful thinking and shows a complete lack of understanding of Darwinian evolution.
Given any two competing mutations of a virus, there are a number of key factors in which one will become dominant.
One is the speed of spread. If that is the main significant factor, as with the Delta, it will move through a community faster than the original Covid virus, and therefore infect people before the original virus has spread to them.
But another is almost certainly vaccine evasion. If we have two variants, and one is better at evading the vaccine triggered immune response, then it will have a better chance of spreading among the vaccinated community, especially as vaccine protection wanes over time. It will make inroads into a population largely protected by vaccines.
If we have both fast transmission and increased vaccine evasion, that mutation would make inroads into the population where earlier variants did not. This is what we may have with the Omicron variant.
But there is no evolutionary law which says that faster transmission and increased vaccine evasion are linked to a milder strain of the virus. Only a milder strain which was both fast transmitting and very vaccine evasive would drive out other mutations, and there is no sign this is the case. As Covid mutations are random, this could happen, but the fact that mutations are random means that it will not be bound to happen.
There is a myth that the Spanish Flu of 1918-1919 became less lethal. But those who contracted the virus - and survived - developed an immunity to the novel strand of influenza. Those who died, didn't! It wasn't that the virus became less lethal, it was that the surviving population had survived because they had immunity, some genetic, and passed it down to their children.
Currently the jury is out on the Omicron virus. However, the hospitalisations in South Africa among unvaccinated, even youngsters, should give us cause for concern. Reports are coming of "an alarming number of them are children under the age of five-years-old" with Omicron, and cases "COVID pneumonia or severe COVID disease". That's a worry because we do not vaccinate younger children here either.
But only around 36% of South Africans are fully vaccinated. How Omicron behaves in a vaccinated population, we still have little idea. It is likely that, as with all variants of Covid, the risk is age related. With current strains of the virus, someone aged 80 who is fully vaccinated essentially takes on the risk of an unvaccinated person of around 50 – much lower, but still not nothing - as deaths of unvaccinated 50 year olds shows.
References
Currently the jury is out on the Omicron virus. However, the hospitalisations in South Africa among unvaccinated, even youngsters, should give us cause for concern. Reports are coming of "an alarming number of them are children under the age of five-years-old" with Omicron, and cases "COVID pneumonia or severe COVID disease". That's a worry because we do not vaccinate younger children here either.
But only around 36% of South Africans are fully vaccinated. How Omicron behaves in a vaccinated population, we still have little idea. It is likely that, as with all variants of Covid, the risk is age related. With current strains of the virus, someone aged 80 who is fully vaccinated essentially takes on the risk of an unvaccinated person of around 50 – much lower, but still not nothing - as deaths of unvaccinated 50 year olds shows.
References
An excellent primer on viruses and how they evolve.
https://www.magonlinelibrary.com/doi/abs/10.12968/denu.2021.48.3.235
Another excellent study on viruses and how they evolve.
Another excellent study on viruses and how they evolve.
https://www.voanews.com/a/south-africa-readies-hospitals-as-omicron-variant-drives-new-covid-19-wave-/6340912.html
Hospitals in South Africa’s Gauteng province, which contains two of the country’s biggest cities, are packed with people infected with the omicron variant. Doctors say most of the patients haven’t been vaccinated, and an alarming number of them are children under the age of five-years-old.
“There’s been a rather rapid rise in hospital admissions with patients who have COVID, whether they’re presenting with COVID pneumonia or severe COVID disease," Dr. Abdullah said.
"All of the hospitals in Tshwane are seeing an upsurge, and the COVID bed occupancy is increasing 30% to 40% per day, over the last few days,” he said.
Some 36% of South Africans are fully vaccinated and President Ramaphosa on Monday urged citizens to get the shots.
https://apnews.com/article/coronavirus-pandemic-science-health-southern-africa-pandemics-2a445501cff8d0354fabcf493418365e
Many critical questions about omicron remain unanswered, including whether the virus causes milder or more severe illness and how much it might evade immunity from past COVID-19 illness or vaccines.
What that could mean for public health remains to be seen. Hanekom said early data from South Africa shows that reinfection rates are much higher with omicron than previous variants, suggesting the virus is escaping immunity somewhat. It also shows the virus seems to be infecting younger people, mostly those who are unvaccinated, and most cases in hospitals have been relatively mild.
But Binnicker said things could play out differently in other parts of the world or in different groups of patients. “It’ll be really interesting to see what happens when more infections potentially occur in older adults or those with underlying health conditions,” he said. “What’s the outcome in those patients?”
Hospitals in South Africa’s Gauteng province, which contains two of the country’s biggest cities, are packed with people infected with the omicron variant. Doctors say most of the patients haven’t been vaccinated, and an alarming number of them are children under the age of five-years-old.
“There’s been a rather rapid rise in hospital admissions with patients who have COVID, whether they’re presenting with COVID pneumonia or severe COVID disease," Dr. Abdullah said.
"All of the hospitals in Tshwane are seeing an upsurge, and the COVID bed occupancy is increasing 30% to 40% per day, over the last few days,” he said.
Some 36% of South Africans are fully vaccinated and President Ramaphosa on Monday urged citizens to get the shots.
https://apnews.com/article/coronavirus-pandemic-science-health-southern-africa-pandemics-2a445501cff8d0354fabcf493418365e
Many critical questions about omicron remain unanswered, including whether the virus causes milder or more severe illness and how much it might evade immunity from past COVID-19 illness or vaccines.
What that could mean for public health remains to be seen. Hanekom said early data from South Africa shows that reinfection rates are much higher with omicron than previous variants, suggesting the virus is escaping immunity somewhat. It also shows the virus seems to be infecting younger people, mostly those who are unvaccinated, and most cases in hospitals have been relatively mild.
But Binnicker said things could play out differently in other parts of the world or in different groups of patients. “It’ll be really interesting to see what happens when more infections potentially occur in older adults or those with underlying health conditions,” he said. “What’s the outcome in those patients?”
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