2nd Spike - any evidence?

[SoberCurious]

Does anyone have any links to scientific arguments for there being a second peak soon please?

[Derbygerbil]

@larrygrylls

Although a CFR of 0.2% is almost certainly too low for the population at large (NYC Covid deaths are 0.26% and although a significant proportion have antibodies, it’s highly improbable that they have achieved herd immunity), the CFR amongst the young is far lower, so yes, a combination of it beginning it’s spread amongst the young and the possible lack of super-spreading events in the early days, could have meant it was here weeks earlier than the earliest reported case... these would be part of the first (and hopefully only) wave though.

[Derbygerbil]

it’s highly improbable that they have achieved herd immunity

By that I mean complete herd immunity sufficient to stop any more infection in NYC.

[pfrench]

I think Israel are seeing an increase in cases

A friend in Israel say that they are particularly seeing raises in cases in young people and school staff. This person is not a member of school staff, so I'm not sure how skewed that bit of information is.

Did anyone look at the tweet I linked about Florida? Opened up, the line has changed. It's not a 'spike', it's a raise in number of cases.

[larrygrylls]

Derby,

'Although a CFR of 0.2% is almost certainly too low for the population at large ....'

You will notice that I used IFR rather than CFR; there is a subtle but important difference. The IFR includes those who become infected but are asymptomatic.

There are still so many unanswered questions. For instance, are there people who are immune to infection without having specific antibodies? That might mean we can achieve herd immunity based on far fewer antibody-positive tests (as from an epidemiological perspective, if you cannot become infected and transmit on, regardless of reason, you are immune).

I do think that we should err on the side of caution with regard to reopening society but, equally, a gradual reopening seems sensible, as it can always be reversed if necessary.

[Haenow]

Genuine question, what’s the difference between an increase in cases vs a second wave/spike? I would think there is always going to be an increase in cases and people mix somewhat more. I don’t think this can be prevented. As long as it’s not an overwhelming number, it’s natural, surely? Lockdown was to flatten the curve, it was never intended that we’d be on a constantly downward motion.

[Derbygerbil]

@larrygrylls

You will notice that I used IFR rather than CFR; there is a subtle but important difference. The IFR includes those who become infected but are asymptomatic.

I agree with what you wrote, but to be pedantic, if total deaths in NYC from Covid are 0.26% of the total population, it’s reasonable to assume that the IFR and the CFR are both above 0.2%!

Regarding antibody tests, I’m increasingly thinking this doesn’t tell us nearly as much as I did only a couple of weeks ago, for the reason you give.

Regarding t-cells, I wonder whether they offer a degree of protection rather than immunity... For instance, in a young, healthy person, they might be enough to fight a low infectious dose without the need for antibodies if otherwise well, but wouldn’t be enough if that person was exposed to a high infectious dose and also run down, in much the same way that we’re all more susceptible to colds and other infections when we’re run down. But I’m no immunologist so can’t speak confidently on this.

[LilyPond2]

covid.joinzoe.com/post/second-wave-covid
This webinar from Zoe app people has a discussion about the likelihood of a second wave.

[peonypower]

The US CDC give an IFR of 0.26pct
This is a conservative figure as it assumes an asymptomatic rate of 35pct, when many studies have shown 50-80pct of people are asymptomatic.

IFR is probably around 0.2pct, comparable to a 'bad' flu season

Given variation in testing rates and the ways in which deaths are recorded differing between countries - and even within countries over time - the only true measure of a spike is excess mortality. We have not seen a second spike anywhere as yet.

There is increasing evidence that only 20pct of populations are susceptible as others have T cell immunity or residual immunity from a prior coronavirus infection (aka a cold)
Even on the Diamond Princess, only around a third of passengers and crew caught the virus despite the average age being higher than average and innate and adaptive immunity weakening with age. Care homes will be higher due to the advanced years of their occupants and their depleted immune system. This is why they need protecting (which is the precise opposite of what has been done in the UK and why our excess mortality is so high)

Anyway, in normal healthy young people we are likely at herd immunity in places like London and a second wave is unlikely.

Stop the insanity now.

(And no, I am not a doctor. Many doctors are surprisingly dense, and of the epidemiologists I work with, far too great a proportion have a vested interest in bigging up the panic. Statisticians are the people speaking sense right now - listen to them)