Coronavirus

[Muddy Retriever]

My thoughts for what they are worth:

Covid 19 reacting T cells would be a more accurate description surely - and how do we know this is not cross reactivity with other Coronaviruses? And they have no antibodies, as that is an easier and more specific test - and they have not yet had Covid 19.

Most have not yet had it; whenever Covid 19 is given a chance - particularly inside with lots of vocal activity - it takes it. The idea that more must have had it is widespread, but I think its proponents under estimate the changes that most people have made to reduce their risk - partly voluntary, partly imposed.

I know the WHO have got a lot wrong, but I think their most recent report was about right.

Do remember - people without symptoms can and do spread it; 2 metres is better than 1 metre - 5 metres is better still; mixing with others inside is much riskier than doing so outside.

Not sure if I'm understanding what you're saying in your first point.

According to the Swedish study

“Moreover, roughly 30 per cent of the blood donors who’d given blood in May 2020 had COVID-19-specific T cells, a figure that’s much higher than previous antibody tests have shown.”

So these are all people who had been in contact with the virus.

https://news.ki.se/immunity-to-covid...sts-have-shown

I suspect that you're right when you say that the majority have not had the virus (although they may have in some of the early hot spots like New York). But I'm open to the possibility that a lot more have had it than official estimates suggest based on antibody tests alone.

[Witton Park]

The idea that more must have had it is widespread, but I think its proponents under estimate the changes that most people have made to reduce their risk - partly voluntary, partly imposed.

I don't under-estimate the changes at all. BUt there was a long time before we made any changes.

We had the virus here for over two months before anyone made any changes other than a week or two's hand washing in mid March prior to lockdown.

No one has yet give an inkling to how an R=4 ish virus has free rein in a population for up 10 weeks and hasn't infected more people, and that's before we get to add those that have caught it since lockdown.

[Oracle]

Steph FYI, quite apart from the clear lack of viable test sets or proper testing of the antibody tests which were rushed through: so are not properly validated and all numbers are suspect)

the premise of these Tcell studies is that antibodies are NOT necessarily formed at all, but the Tcells remain as specific resistance with long term memory by identifying and reacting to covid specific peotides: even in population not exposed to covid itself. If that is true ( and the jury is still out) then antibody testing can never give estimates of herd immunity.

The possibility is past epidemics have left non specific resistance, and since many of these bugs start in bat/ bird populations in China, it can be supposed that resistance spreads to areas that interact with them.
That could be why China, South Korea and Hong Kong numbers are low compare to more distant populations like us.

There is a lot still unknown. That populations have reacted so differently, implies one countries policies are not the only indeed may not be the major contributor.

Ps - my thoughts are gleaned from OH, who ran a biotech lab as tech director, so knows a thing or two!

The anti body testing data is not robust enough at the moment to provide accurate numbers on those who have been infected or what immunity can be expected.

The statistical reports out there from the scientific community advise up to a 30% infection rate for England, others have suggested about half that, I think the govt put a figure of nearly 20% for London back in May with the rest of the country lower, but certainly more than 5%, all very interesting stuff but you know what they say about stats.

[Mike T]

Not sure if I'm understanding what you're saying in your first point.

According to the Swedish study

“Moreover, roughly 30 per cent of the blood donors who’d given blood in May 2020 had COVID-19-specific T cells, a figure that’s much higher than previous antibody tests have shown.”

So these are all people who had been in contact with the virus.

https://news.ki.se/immunity-to-covid...sts-have-shown

I suspect that you're right when you say that the majority have not had the virus (although they may have in some of the early hot spots like New York). But I'm open to the possibility that a lot more have had it than official estimates suggest based on antibody tests alone.

It looks like the T cells are "specific" for Covid 19, but they might be reacting to an identical or similar epitope - shape - on a different Coronavirus - so called cross reactivity. So they may not have been in contact with Covid 19, but one of the Coronaviruses that can cause the "common cold".

[Graham Breeze]

Not to pick over would or could

Mmmh.

So I could die if I jump off this cliff and I would die if I jump off this cliff are pretty much the same to you?

[Muddy Retriever]

It looks like the T cells are "specific" for Covid 19, but they might be reacting to an identical or similar epitope - shape - on a different Coronavirus - so called cross reactivity. So they may not have been in contact with Covid 19, but one of the Coronaviruses that can cause the "common cold".

That isn't what they are saying.

New research from Karolinska Institutet and Karolinska University Hospital shows that many people with mild or asymptomatic COVID-19 demonstrate so-called T-cell-mediated immunity to the new coronavirus, even if they have not tested positively for antibodies. According to the researchers, this means that public immunity is probably higher than antibody tests suggest.

[Witton Park]

Mmmh.

So I could die if I jump off this cliff and I would die if I jump off this cliff are pretty much the same to you?

I can go back a few years to should and must, but I think it best not to

[Mike T]

That isn't what they are saying.

New research from Karolinska Institutet and Karolinska University Hospital shows that many people with mild or asymptomatic COVID-19 demonstrate so-called T-cell-mediated immunity to the new coronavirus, even if they have not tested positively for antibodies. According to the researchers, this means that public immunity is probably higher than antibody tests suggest.

Thanks for the correction - cross reactive immunity is almost certainly better than none.

[Mike T]

I don't under-estimate the changes at all. BUt there was a long time before we made any changes.

We had the virus here for over two months before anyone made any changes other than a week or two's hand washing in mid March prior to lockdown.

No one has yet give an inkling to how an R=4 ish virus has free rein in a population for up 10 weeks and hasn't infected more people, and that's before we get to add those that have caught it since lockdown.

I can only speak with certainty about myself and those I know - but my partner and I started changing our behaviour quite dramatically in early March, and I was advising those I know - club members, B+B owners, yoga attendees - to do the same; there will have been plenty of others doing this I'm sure. Of course there were those who refused to change their ways except where they had to, but they will have still been reducing their risk, even if they tried not to do so.

The situation in the US shows what can happen if you let it.

[Mike T]

So they have been hiding the local pillar 2 data!

https://www.ft.com/content/301c847c-...b-8e66933d423a