What is going on in Brazil?

[KenDodd]

Are the public taking their own lockdown measures? Or is covid just going away? Or something else?

www.worldometers.info/coronavirus/country/brazil/

@Derbygerbil
I'd better stop posting without properly reading the thread! It's the second time I've done it today. I skimmed through and thought posters were saying Brazil's figures had dropped. Assume that's not the case? And Japan? I'm curious to know more about lots of places actually, including Germany and Italy.

Sweden is quite obviously herd immunity. Same for Brazil and the US sunbelt. Probably the same story in London and New York although harder to be sure because of lockdowns. And possibly much of the world.

There are a lot of people who are very anti- herd immunity who'll tell you that it's not, but the patterns are hard to explain any other way.

Something else is going on in Japan though. Either the population has some sort of "immunological dark matter" or people are getting it and not becoming very sick - they're not testing much.

@Derbygerbil

There was speculation, based on what happened in NY/London, that once 20% of the population (or even as low as 10%) got infected (including asymptomatic cases) that spread dropped dramatically.

Given antibody rates in some hotspots are 60%+, a more plausible explanation would be that the 10-20% are those that continue to mix whilst most socially distance, either completely, or enough to avoid infection.

I've been thinking about this and wondering could it be explained by the fact that in those hotspots it all happened so fast that the immunity didn't have chance to have an effect. If it takes a few weeks after infection for antibodies to kick in then essentially the virus spread through those "virgin" places with no blockers. However now, maybe the 1 in 10 or 1in 5 people it encounters who have immunity and break the chains of transmission are enough to have a significant effect (perhaps in tandem with social distancing, isolating with symptoms and few super spreader events).

And to add to the above, especially since that 10-20% of people are not random. They are likely to be:

• the people most susceptible to the virus
• very sociable people who have lots of contacts hence caught it initially
• those who work in professions where they could spread it to the most people and to the most vulnerable people (medics, care home workers etc)
• super spreaders

This must all help in changing the course of the epidemuc curve a subsequent time

I think a lot comes down to how people behave and how scared they are, particularly the most vulnerable people.

For example a lot of swedes changed their behaviour to similar semi-lockdown even though it wasn’t imposed (eg www.thelocal.se/20200409/how-people-in-sweden-have-changed-their-behaviour-to-avoid-the-coronavirus )

There was another study that showed how many people did lockdown without it being imposed by the central government. The same thing is causing the lower death rate at the moment compared to March - people in care homes etc are being far far more careful. I would expect the same is happening in Brasil.

Found an interesting link for Brasil

This paper was written on 28th May, predicting the future of Brasil’s pandemic numbers based on the restrictions they already had in place and how well they were working to reduce transmission in May.

www.tandfonline.com/doi/full/10.1080/22221751.2020.1785337

From what I can see (figure 1, reading log plots by eye), their prediction looks identical to the current data on worldometer. So it’s not unexpected.

I’m not sure how much is government mandated rules on masks etc and how much is individuals making their own decisions to stay home (anyone from Brasil on here?) but it is not unexpected.

I have a member of staff from Brazil. This is what she has told me...

Their President is an authoritarian version of Trump (that's not a secret, so I already knew that). There is little in the way of formal guidance or rules in place. The middle and upper classes are operating by their own versions of cautionary actions as far as they can, so social distancing, masks, hand washing etc. However, large numbers of the poor are unable to do so - they need to work. Plus many live in conditions where there is overcrowding and little sanitation - running water can be a luxury.

To the north of the country, US loggers etc., are still operating in and out of the country, bringing the virus to isolated areas and first peoples, and there is a real risk that some of the first people, who already have limited immunity to first world diseases, may be wiped out. There have been reports, although these cannot be verified, that attempts are being made to deliberately wipe out the Amazonian people by exposing them to the virus. Given Bolsonaro has been accused - with cause - of such actions in the past, and has made no secret of wishing to eradicate the indigenous peoples, this would not be a stretch to believe it; and the US has form for similar measures in the past.

Oh, and to add, she also said that despite all this there is little hysteria about it mostly. Brazil - and especially the poor - have more than enough things that can kill them. This is just another risk. So there is a more sanguine attitude. If you've survived malaria, zika, poverty, the government, the gangs, this is just another thing to get past...

@Mummabeary

I agree. There will be significant numbers of people in large cities who were able to isolate, hunker down and work from home as the storm broke. In NYC, I read that a deprived part of Brooklyn has antibodies levels of over 70%, whereas in more wealthy areas, it was more like 10% (which is still very high but NYC was hit worse than any other major city). If everyone went back entirely to their pre-March lives in London, NYC, Stockholm and Madrid, I’d be astonished if there wasn’t a big infection spike - perhaps not as steep as the first one, but sizeable and longer lasting (if no counter measures are put in place
to mitigate the rise as happened in March). As for other areas, broadly speaking, they are nowhere near herd immunity levels.

Herd immunity is not a thing.

People keep mentioning antibodies but as I understand it, not everyone develops them or retains them for that long, and its T cells that confer longer term immunity.
So antibody tests will understate the number of people who have had covid.

@onelinelinda

Herd immunity may not completely eradicate Covid, but if a significant enough proportion of the population were to be infected, it would drastically reduce Covid’s spread to the level that suppression measures would be unnecessary.

@MaxNormal

That’s true, but there have been many studies that have shown very high levels of antibodies (60-90%) in diverse populations from Peru, Mumbai and NYC neighbourhoods. This indicates that most people will produce antibodies, even if t-cells have an important role.

Don’t a lot of Swedish people go to their holiday homes in the summer so that might have had an impact on their figures, so leave the higher density areas and work places and go to more rural areas?

Don’t a lot of Swedish people go to their holiday homes in the summer so that might have had an impact on their figures, so leave the higher density areas and work places and go to more rural areas?

I can remember back in April, the news saying that the Swedish health officials strongly urged those in Stockholm not to go into the country over Easter.... I expect that advice may have relaxed over the summer.

It was too late in April, I know several old colleagues who'd all gone in early March because offices that could work remotely switched over. I don't think any of them were ill, but nobody knew that, and it sounded like a sensible plan for riding out the spring and summer nicely distanced. It's the same with all our uni students (including those who were kicked out of halls); they travelled home and it didn't seem like a bad idea in March, lock down with your family instead of alone. But of course it will have helped spread in many cases.

@onlinelinda

Herd immunity is not a thing.

Yes it is. That’s why people who can’t have vaccines are protected by other people having them.