9 ms·

The big question is whether the disease is genuinely milder, or whether the mild cases are just a consequence of the virus infecting people who are partially im

The big question is whether the disease is genuinely milder, or whether the mild cases are just a consequence of the virus infecting people who are partially immune (due to the immune escape properties). We’ll learn the answer in a few weeks when the strain has had a chance to infect the old and unwell and we will see if the hospitalizations and deaths increase.

GeekyBear 5y ago
>The big question is whether the disease is genuinely milder, or whether the mild cases are just a consequence of the virus infecting people who are partially immune The initial data says that even though South Africa has a much lower vaccination rate, omicron is mild. From today: > lack of high death and hospitalization rates, despite the fact that Omicron has spread at breakneck speed across the country and accounts for most of the infections over the past three weeks, is the most glaring difference. https://www.cbsnews.com/news/covid-omicron-variant-south-africa-low-deaths-and-hospitalizations/ https://www.cbsnews.com/news/covid-omicron-variant-south-afr...
- peteradio 5y ago
  Dude that article is saying its due to underlying immunity according to the source vaccinologist: > Professor Shabir Madhi, a vaccinologist at Wits University in Johannesburg who ran trials on AstraZeneca's COVID vaccine, believes it is the substantial percentage of the population in places like Gauteng province — which includes the urban hubs of Pretoria and Johannesburg and has seen a dramatic uptick in new infections — with underlying T-cell immunity that is preventing the disease from becoming more severe. It should bring deep shame on people to see their own source material used directly in contradiction to their claim.
- fshbbdssbbgdd 5y ago
  It’s believed that 70%+ of South Africa have already had covid, and there is substantial protection from severe cases on reinfection.
  - GeekyBear 5y ago
    Is there any reason to believe that having a large number of previously infected individuals is unique to South Africa?
    - MatteoFrigo 5y ago
      https://covidestim.org/ https://covidestim.org/ provides estimates of the percentage of previously infected individuals by US state. I happen to be in Massachusetts, for which they estimate around 50% previously infected, with error bars. So a bit lower than South Africa, but not too far in the big scheme of things. The UK provides some estimates of seroprevalence in blood donors (thus a skewed sample): https://www.gov.uk/government/publications/covid-19-vaccine-surveillance-report https://www.gov.uk/government/publications/covid-19-vaccine-... (Figure 3). These estimates aren't quite what you are looking for, but one test is sensitive to previous infection and estimates 20% previously infected, whereas another test is sensitive to (infection OR vaccine) and estimates ~100%. Basically, in that population, pretty much everybody has some kind of antibodies. To answer your question, I would say that SA doesn't look particularly unique.
    - fshbbdssbbgdd 5y ago
      SA isn’t unique, but it’s the location of the study this post is about, so the stats there are relevant.
- tgsovlerkhgsel 5y ago
  One of the issues of fast spread is that hospitalizations and deaths lag behind infections for a few weeks. If you don't correct for it, it's easy to see "10x as many cases but few deaths" just because cases went up so quickly that deaths didn't start yet. Of course, this can be corrected for, and I'd expect a good study to do so - but I would NOT trust a typical news article to make the distinction, nor would I trust it to skip the temptation to misinterpret the study for a more interesting headline.
  - spurgu 5y ago
    A few weeks? From what I've seen staring at case/death charts I'd say it's somewhere around two.
- WillPostForFood 5y ago
  The last paragraph of the WaPo article we are all commenting on: “South Africa has a quite high seroprevalence of prior infection, particularly after delta, and in some parts of South Africa up to 80 percent of people were exposed to previous infection,” she said. “We don’t think it’s a question of virulence, but more a question of exposure to vaccination and prior infection, so we would be cautious to try and interpret that this is a less virulent strain. We’ll have to see what happens in other parts of the world before we make a call on this.”
  - GeekyBear 5y ago
    A study was done testing samples pulled from ~1.5 million blood donations in the US looking for Covid antibodies. >By May 2021, the combined infection- and vaccination-induced seroprevalence estimate increased to 83.3% (95% CI, 82.9%-83.7%) https://jamanetwork.com/journals/jama/fullarticle/2784013 https://jamanetwork.com/journals/jama/fullarticle/2784013 The delta variant surge didn't hit the States until after this study concluded, so one would expect the numbers to be quite a bit higher today.
- inciampati 5y ago
  The lower vaccination rate is more than offset by the high rate of prior infection. This might also mean that omicron is mild if you have been previously infected. Populations with high vaccination rates and low infection rates might be at risk. Or they could be fine. We can't extrapolate to them from the situation in SA.
Mindwipe 5y ago
Hospitalisations and deaths will likely increase regardless, as so many more people will be infected, even if it's proportionately less dangerous to a given individual. But I agree, more data in the next few weeks are what we need to make genuine determinations.
standardUser 5y ago
"...or whether the mild cases are just a consequence of the virus infecting people who are partially immune" There are not a lot of people out there still who are not partially immune at this point, due to vaccine, recovery or both. It varies by region of course, but it's certainly true in most parts of the US.

GeekyBear 5y ago

>The big question is whether the disease is genuinely milder, or whether the mild cases are just a consequence of the virus infecting people who are partially immune The initial data says that even though South Africa has a much lower vaccination rate, omicron is mild. From today: > lack of high death and hospitalization rates, despite the fact that Omicron has spread at breakneck speed across the country and accounts for most of the infections over the past three weeks, is the most glaring difference. https://www.cbsnews.com/news/covid-omicron-variant-south-africa-low-deaths-and-hospitalizations/ https://www.cbsnews.com/news/covid-omicron-variant-south-afr...

peteradio 5y ago
Dude that article is saying its due to underlying immunity according to the source vaccinologist: > Professor Shabir Madhi, a vaccinologist at Wits University in Johannesburg who ran trials on AstraZeneca's COVID vaccine, believes it is the substantial percentage of the population in places like Gauteng province — which includes the urban hubs of Pretoria and Johannesburg and has seen a dramatic uptick in new infections — with underlying T-cell immunity that is preventing the disease from becoming more severe. It should bring deep shame on people to see their own source material used directly in contradiction to their claim.
fshbbdssbbgdd 5y ago
It’s believed that 70%+ of South Africa have already had covid, and there is substantial protection from severe cases on reinfection.
- GeekyBear 5y ago
  Is there any reason to believe that having a large number of previously infected individuals is unique to South Africa?
  - MatteoFrigo 5y ago
    https://covidestim.org/ https://covidestim.org/ provides estimates of the percentage of previously infected individuals by US state. I happen to be in Massachusetts, for which they estimate around 50% previously infected, with error bars. So a bit lower than South Africa, but not too far in the big scheme of things. The UK provides some estimates of seroprevalence in blood donors (thus a skewed sample): https://www.gov.uk/government/publications/covid-19-vaccine-surveillance-report https://www.gov.uk/government/publications/covid-19-vaccine-... (Figure 3). These estimates aren't quite what you are looking for, but one test is sensitive to previous infection and estimates 20% previously infected, whereas another test is sensitive to (infection OR vaccine) and estimates ~100%. Basically, in that population, pretty much everybody has some kind of antibodies. To answer your question, I would say that SA doesn't look particularly unique.
  - fshbbdssbbgdd 5y ago
    SA isn’t unique, but it’s the location of the study this post is about, so the stats there are relevant.
tgsovlerkhgsel 5y ago
One of the issues of fast spread is that hospitalizations and deaths lag behind infections for a few weeks. If you don't correct for it, it's easy to see "10x as many cases but few deaths" just because cases went up so quickly that deaths didn't start yet. Of course, this can be corrected for, and I'd expect a good study to do so - but I would NOT trust a typical news article to make the distinction, nor would I trust it to skip the temptation to misinterpret the study for a more interesting headline.
- spurgu 5y ago
  A few weeks? From what I've seen staring at case/death charts I'd say it's somewhere around two.
WillPostForFood 5y ago
The last paragraph of the WaPo article we are all commenting on: “South Africa has a quite high seroprevalence of prior infection, particularly after delta, and in some parts of South Africa up to 80 percent of people were exposed to previous infection,” she said. “We don’t think it’s a question of virulence, but more a question of exposure to vaccination and prior infection, so we would be cautious to try and interpret that this is a less virulent strain. We’ll have to see what happens in other parts of the world before we make a call on this.”
- GeekyBear 5y ago
  A study was done testing samples pulled from ~1.5 million blood donations in the US looking for Covid antibodies. >By May 2021, the combined infection- and vaccination-induced seroprevalence estimate increased to 83.3% (95% CI, 82.9%-83.7%) https://jamanetwork.com/journals/jama/fullarticle/2784013 https://jamanetwork.com/journals/jama/fullarticle/2784013 The delta variant surge didn't hit the States until after this study concluded, so one would expect the numbers to be quite a bit higher today.
inciampati 5y ago
The lower vaccination rate is more than offset by the high rate of prior infection. This might also mean that omicron is mild if you have been previously infected. Populations with high vaccination rates and low infection rates might be at risk. Or they could be fine. We can't extrapolate to them from the situation in SA.

Mindwipe 5y ago

Hospitalisations and deaths will likely increase regardless, as so many more people will be infected, even if it's proportionately less dangerous to a given individual. But I agree, more data in the next few weeks are what we need to make genuine determinations.

standardUser 5y ago

"...or whether the mild cases are just a consequence of the virus infecting people who are partially immune" There are not a lot of people out there still who are not partially immune at this point, due to vaccine, recovery or both. It varies by region of course, but it's certainly true in most parts of the US.