It sounds like the first peak managed to infect 75% of the population? If so, a second, similar, peak, at 1% case-fatality-rate is likely to case 20,000 deaths in the city alone.
1) There's no way of knowing what percentage of the population has been infected.
2) You're assuming that this strain can re-infect the same people, which is speculation.
3) You're assuming that this strain will be just as fatal as the original strain after re-infection, which is speculation.
That's useful, thanks. Though an estimate of seroprevalence based on a blood bank survey (both of these are from the same group, using the same method) has issues with bias (in particular, see the number of re-weightings performed and the huge impact of these adjustments in Figure 2A of the second link), that makes me hesitant to believe any claim starting with "75% of the population was infected, therefore..."
In other words: if we're seeing a resurgence in cases now, the parsimonious answer is that the blood-bank survey estimate was wrong, not that the virus is escaping all immunity. My prior probability of this explanation is dramatically increased when I see that the seroprevalence data was adjusted upward by a factor of 2-3 to account for "seroreversion" (which is essentially guessing).
"If you were to ask me right now, what's most concerning of all the things that I've heard so far, it's the fact that they are reporting a sudden increase in cases in Manaus, Brazil," virus expert Jeremy Luban at the University of Massachusetts told NPR two weeks ago before the variant arrived in the United States. "Manaus already had 75% of people infected [in the spring of last year]."
Regarding point 3 -- it is, of course, speculation, but for millenia the most-effective method of weather forecasting was constancy: "Tomorrow will be just like today". It could be better, it could be worse, but if we don't know anything, assuming that it will be similar seems like a good bet.
Edit: On first read, I missed "on reinfection" for point 3. Agreed. One definitely hopes that on reinfection, cases will be more mild.
Yep, that quote is an opinion from one person. "Virus expert" or no, it is still speculation. The fact that said expert is confidently claiming that 75% number makes me doubt his opinion. We can't confidently estimate the proportion of people infected in the US or Europe. I don't know how you'd begin to claim such a thing in Brazil, where the access to testing and data reporting is quite poor.
for millenia the most-effective method of weather forecasting was constancy: "Tomorrow will be just like today"
I disagree that this like predicting the weather. The weather has consistent seasonal patterns that give you ~90% (brown number) of the story (ironically, this virus is also probably strongly seasonal, but I digress).
Here, we're engaged in speculation that some "new strain" might be worse than the existing strain. It's the opposite of using long-term trends to predict the future. It's a bit like claiming that every new typhoon is going to be the worst one ever, because it's different than the last typhoon in some way.
Comments
1) There's no way of knowing what percentage of the population has been infected.
2) You're assuming that this strain can re-infect the same people, which is speculation.
3) You're assuming that this strain will be just as fatal as the original strain after re-infection, which is speculation.
Researchers who tested blood samples from blood banks in Manaus estimated 66% by the end of the first wave [1]. That rises to 76% by October [2].
[1] https://www.nature.com/articles/d41586-020-02948-4
[2] https://science.sciencemag.org/content/371/6526/288
That's useful, thanks. Though an estimate of seroprevalence based on a blood bank survey (both of these are from the same group, using the same method) has issues with bias (in particular, see the number of re-weightings performed and the huge impact of these adjustments in Figure 2A of the second link), that makes me hesitant to believe any claim starting with "75% of the population was infected, therefore..."
In other words: if we're seeing a resurgence in cases now, the parsimonious answer is that the blood-bank survey estimate was wrong, not that the virus is escaping all immunity. My prior probability of this explanation is dramatically increased when I see that the seroprevalence data was adjusted upward by a factor of 2-3 to account for "seroreversion" (which is essentially guessing).
Regarding points 1 and 2, from the article:
"If you were to ask me right now, what's most concerning of all the things that I've heard so far, it's the fact that they are reporting a sudden increase in cases in Manaus, Brazil," virus expert Jeremy Luban at the University of Massachusetts told NPR two weeks ago before the variant arrived in the United States. "Manaus already had 75% of people infected [in the spring of last year]."
Regarding point 3 -- it is, of course, speculation, but for millenia the most-effective method of weather forecasting was constancy: "Tomorrow will be just like today". It could be better, it could be worse, but if we don't know anything, assuming that it will be similar seems like a good bet.
Edit: On first read, I missed "on reinfection" for point 3. Agreed. One definitely hopes that on reinfection, cases will be more mild.
Yep, that quote is an opinion from one person. "Virus expert" or no, it is still speculation. The fact that said expert is confidently claiming that 75% number makes me doubt his opinion. We can't confidently estimate the proportion of people infected in the US or Europe. I don't know how you'd begin to claim such a thing in Brazil, where the access to testing and data reporting is quite poor.
I disagree that this like predicting the weather. The weather has consistent seasonal patterns that give you ~90% (brown number) of the story (ironically, this virus is also probably strongly seasonal, but I digress).
Here, we're engaged in speculation that some "new strain" might be worse than the existing strain. It's the opposite of using long-term trends to predict the future. It's a bit like claiming that every new typhoon is going to be the worst one ever, because it's different than the last typhoon in some way.