We can’t achieve herd immunity by letting Covid spread (or with the current vaccines)

[Turquoisesol]

It isn’t really possible to reach herd immunity and Britain will not do this by deliberately infecting large numbers of people. Many people seem to be under the impression that by letting it rip we will eventually reach herd immunity but it almost certainly won’t happen.

www.nature.com/articles/d41586-021-00728-2

Yes, different strains of flu have different starting values for R. One of the factors influencing that is pre-existing exposure to similar flu strains. It doesn’t ‘drop over time’ all by itself, if drops because there are fewer susceptible people to infect.

Surely the R0 of a novel virus will always be initially very high as every individual will be entirely susceptible. As immunity grows, the R value decreases.

Flu has been endemic for hundred of years and even new strains of flu will be tempered by the widespread immunity in the community.

Covid is no longer novel and levels of immunity are increasing all the time. That is bound to have an impact.

Yes the point I was trying to make, not very clearly, that the starting value with no immunity of 1.8 in the 2018 pandemic was a lot lower than the starting value for delta of 6.

It will be fine eventually as we understand more about the virus and have better vaccines and treatments. It will just take time. Its still early days.

@Indigopearl

Yes the point I was trying to make, not very clearly, that the starting value with no immunity of 1.8 in the 2018 pandemic was a lot lower than the starting value for delta of 6.

But it would be, because there is a huge amount of immunity to flu in the population. It might have been a new variant of flu but previous exposure to other variants will still have impacted R0.

@IcedPurple

Would anyone else like to ban the expression 'letting it rip'?

Absolutely yes.

Right some more sensible stuff:

James Ward@jamesward73
I think I'm going to let you make your own judgements on this one. (note I've included specimen dates up to 15th July, so the last couple of data points are incomplete, but I think the pattern is already clear)

in case you're in any doubt that this is mostly a football-linked spike in cases, see the gender divide in case growth rates over the last few days:

A few points around that

Oliver Johnson @bristoliver
Resolutely sticking to the view that I don't know when and how large the UK peak will be, and that the range of the uncertainty around any reasonable forecast probably includes both "it's basically fine" and "we have a very serious problem".

I don't think this is a complete cop out, because we genuinely don't know how Monday goes. Paradoxically, if enough people believe it'll all be fine it may well not be, but if enough people believe it won't it might be. Try modelling that.

Definitely we are currently in a phase of exponential growth for cases, admissions and deaths, and you can easily extrapolate that growth rate forward six weeks and hit some scary numbers.

But equally, the point about the "grains of rice on a chessboard" thing was that the guy ran out of rice. In other words, this thing has to curve at some stage, but the hard part is telling when and by how much.

You can make all kinds of convincing arguments based on football, school holidays, weather and back of envelope calculations about immunity. But we've been making these arguments for a few months (and I'm guilty of that too) and still we're on a pretty straight line.

So, as usual, I think it turns into an argument about the precautionary principle. I'm not hearing as many people saying January admissions levels (4k/day) are downright impossible as I used to, and even a small probability of a really bad outcome affects the risk balance a lot.

The problem is really one of running out of road, I think. When I got this charming email t.co/tAVjhnCP2o we'd just hit 100 admissions, so had more than five doublings to play with before hitting 4k. That's now under three, and one of those may be baked in from case lag.

I'm not offering any solutions, just advocating humility in the face of uncertainty (because small changes in growth rate make a big difference over a month), and to always look at the error bars and not just the central forecast. (Oh, and get vaxxed and stay outside if you can).

Peter Rankin @rankinpeter
For those in England worried that rates look like they are going through the roof, just remember that it can turn around VERY quickly once schools break up and you're out of the football!!

A good sign is that the rate of growth is slowing in areas which were early hotspots in England (particularly the NW).

This isnt being picked up in a lot of data because there are more places which are still on high rates of growth.

This could be because so many kids have already been kicked out of school (which wouldn't bode well for the autumn) though.

The Netherlands found that opening nightclubs was a disaster too.

But for the most part im not too worried about next week because so many people haven't exactly been following the rules in the last few weeks...

Those who say there's no other option than letting it spread exponentially (as we're doing now) or lockdown - have you really not seen what's been achieved in other countries?

We have family in a US state - no lockdown after the first and their case rate is 1 in 100k over 7 days. They did all this with mask mandates and proper mitigations in schools (ventilation, air filtration, smaller class sizes, social distancing, blended learning and every child got a free state provided laptop). Excellent testing system and contact tracing suppressing any outbreaks quickly and effectively. More recently vaccines, but they didn't have the winter surge like we had - rates went up a bit, and they tightened their measures and got control again.

Obviously far less death and disability.

Loads and loads of countries have managed to live with the virus with good contact tracing, testing, properly funded and supported isolation, and decent mitigations.

Why people aren't demanding this level of public health measures I don't know. If you want to avoid further lockdown it's the only way.

That article is saying vaccine hesitancy and the logistics of getting the world vaccinated quickly enough looks like it will make herd immunity impossible

If we had 90+,% of the world ( including children) vaccinated very quickly we could to all intents and purposes eradicate Covid.

Since that seems unachievable, we will need to settle for turning it into a disease that only kills the quite old and fairly vulnerable in large numbers in a short space of time to one that kills the very old and very vulnerable but not all in one go, more spread out over many years

@GoldenOmber

And for comparison, R for covid the UK right now is about 1.3, and that’s mostly not because of restrictions but because of how much population immunity we have now thanks to the vaccine programme (and a bunch of previous infections). We won’t ever see the unchecked R for delta in this country, because we’ve checked it.

Good point

I thought the idea was to force a peak in August rather than later when schools are. back and winter pressures have begun. I don't think they have claimed it is anything to do with herd immunity recently. I also think they are regretting not opening up in June when figures where lower and the peak would have been earlier. I'm in a area that was one of the first noted for having the delta variant and has one of the highest rates in the country. Although cases are still rising they aren't actually increasing that much so I think we are probably nearing the top of the peak now, although the rest of the country may be up to a month behind us. Deaths are almost non existent and although local hospitals have recently cancelled elective surgery this is due to the self isolation rules, so there are plenty of empty beds but too many staff off as their kids are isolating to man them.

Not liking the look of that deaths graph.

Exponential growth, just as I've been warning everyone for weeks.

just as I've been warning everyone for weeks

Except 'everyone' has been for weeks over all these 'warnings', not really understanding what you are trying to do. Do you have a bet on at the bookies?

Given there is waning immunity from vaccines, what exactly is the point of vaccinating people then protecting them from exposure to covid? Surely there is an argument that you retain good immunity by continued exposure to the real thing? As we’re not ever going to eradicate covid, it actually is pretty pointless vaccinating then not mixing, imvho. So, what is the solution? How much mixing is acceptable? Who should and should not be able to mix, and from which age groups, from a public health perspective rather than an individual “fairness” perspective? How much mitigation is necessary to ensure control over the situation???

@Sparklingbrook

just as I've been warning everyone for weeks

Except 'everyone' has been for weeks over all these 'warnings', not really understanding what you are trying to do. Do you have a bet on at the bookies?

I've been trying to warn people that our government's roadmap is a one way ticket to a devastating Third Wave.

No one listened.

And it turned out I was right.

There will be increase in cases due to removal of restrictions

It’s happening in Summer rather than Winter for reasons Chris Whitty outlined

I have no idea why people are posting as pp unless it’s a need for constant attention

I've been trying to warn people that our government's roadmap is a one way ticket to a devastating Third Wave.

No one listened.

And it turned out I was right

At last something to makes you happy. The glee that comes across in your post is tangible. I guess (hope), your work here is done.

I've been trying to warn people that our government's roadmap is a one way ticket to a devastating Third Wave.

No one listened.

Yes, I've seen your extensive daily warnings, they appear on every thread. What I don't understand is why you are so obsessed with 'warning' everyone. Why does it matter if someone on the internet is right or wrong? Unless there's a huge prize maybe?

I don’t get why the pp thinks it was unexpected though?

It’s obvious cases will rise that’s the point of doing it now but winter

I don’t see there’s anything to gloat about

@Sunshinegirl82

The human race is nothing if not tenacious! We've survived every major infectious disease thrown at us as a species for thousands of years.

I understand people are anxious but the way people talk you'd think it was 100% lethal and this was the end of time. I do think we need to keep a bit of perspective.

Yep. Some of the comments on here are quite ridiculous. Body bags, end times.

@NannyAndJohn

Seriously you need help

It is frustrating continually watching the government make these wrong decisions though. Sometimes it is just a need to discuss is the reason for posting?