3 ms·

It is not evident yet that a large proportion of the population will be immune. The virus has some similarities with the common cold and it is well known that

It is not evident yet that a large proportion of the population will be immune. The virus has some similarities with the common cold and it is well known that immunity does not last for the common cold. Having COVID without symptoms (asymptomatic) does not mean that you are immune and you are still infectious. Edit: > even now a lot of people are having covid w/o any symptoms at all The last estimate I saw (last week I think) for Stockholm was that only roughly ten percent of the local population had COVID,

xlm1717 6y ago
Immunity doesn't last for the common cold because there's so many viruses that cause it.
- AstralStorm 6y ago
  Uhm, about 6-20 very common ones,, though total count is close to 200. And these have variants. But even within just betacoronavirus 1 OH49 (10% of colds or thereabouts) immunity is not persistent. It is just mild enough. There's another one alphacoronavirus in about 5% of colds that is much worse. (Not counting SARS group.) Mind you parallel infection with multiple viruses is common.
goalieca 6y ago
The original herd immunity "estimates" of 60% were 1-1/Ro. This never considered heterogeneous spread and it assumed everyone was equally susceptible. It's hard to estimate prevalance because PCR testing has a large false negative rate. It depends highly on which day of the infection you're tested and even then the peak rate is still quite miserable for trying to find it. Serorevalence is also tricky as we trade off false positive for false negative and the antibodies decline after a few months. That's not to say that memory B cells can't spin up production on demand though. Then there's the whole t-cell response which may play a bigger role in asymptomatic cases. All in all, its understood that antibody testing is underestimating infection rates. Regardless of what values we think herd immunity should have, it's pretty clear that places like Sweden have seen the death peak and then tail off without any major change in distancing policies. If anything, people are relaxing more with time. edit: I should mention that since march, we do have better treatment options and we have stepped up our game protecting care homes all over the world including Sweden which saw a majority of deaths from those facilities. This is why it's important to look at trends in other countries as well.
- AstralStorm 6y ago
  Generally if this virus is anything like other coronaviruses, it will adapt. And this flare up regularly even if immunity is present. That's how it made the interspecies jumps after all. So at best it will be a perpetual game of cat and mouse, like it is with flu, but with higher stakes.
  - goalieca 6y ago
    Let's assume this virus will be endemic. Why would we assume that the second infection would be any worse than the first? Our immune system is highly adaptive and generally does very well. In fact, we've now got good evidence that there is cross-protection from antibodies and t-cells from other coronaviruses in circulation.

xlm1717 6y ago

Immunity doesn't last for the common cold because there's so many viruses that cause it.

AstralStorm 6y ago
Uhm, about 6-20 very common ones,, though total count is close to 200. And these have variants. But even within just betacoronavirus 1 OH49 (10% of colds or thereabouts) immunity is not persistent. It is just mild enough. There's another one alphacoronavirus in about 5% of colds that is much worse. (Not counting SARS group.) Mind you parallel infection with multiple viruses is common.

goalieca 6y ago

The original herd immunity "estimates" of 60% were 1-1/Ro. This never considered heterogeneous spread and it assumed everyone was equally susceptible. It's hard to estimate prevalance because PCR testing has a large false negative rate. It depends highly on which day of the infection you're tested and even then the peak rate is still quite miserable for trying to find it. Serorevalence is also tricky as we trade off false positive for false negative and the antibodies decline after a few months. That's not to say that memory B cells can't spin up production on demand though. Then there's the whole t-cell response which may play a bigger role in asymptomatic cases. All in all, its understood that antibody testing is underestimating infection rates. Regardless of what values we think herd immunity should have, it's pretty clear that places like Sweden have seen the death peak and then tail off without any major change in distancing policies. If anything, people are relaxing more with time. edit: I should mention that since march, we do have better treatment options and we have stepped up our game protecting care homes all over the world including Sweden which saw a majority of deaths from those facilities. This is why it's important to look at trends in other countries as well.

AstralStorm 6y ago
Generally if this virus is anything like other coronaviruses, it will adapt. And this flare up regularly even if immunity is present. That's how it made the interspecies jumps after all. So at best it will be a perpetual game of cat and mouse, like it is with flu, but with higher stakes.
- goalieca 6y ago
  Let's assume this virus will be endemic. Why would we assume that the second infection would be any worse than the first? Our immune system is highly adaptive and generally does very well. In fact, we've now got good evidence that there is cross-protection from antibodies and t-cells from other coronaviruses in circulation.