R value - what does it mean?

Thanks, Alexa.

PS I quoted Rockgran

"I don't think the virus is alive as such -it is more like a poison. It becomes active when it has a host. Without a host it decays. If we could stop passing it around it might just disappear."

I like the analogy with poison! Unlike mice that have baby mice, or bacteria that split themselves up into more bacteria, virus uses virally "poisoned" cells from a host to multiply.

As any relaxation of the lockdown will inevitably lead to a rise in R, there should be no relaxation until R is at 0.5 or thereabouts. Relaxation measures should be introduced gradually and the effect of each measure monitored.

If we had a second wave of infection, it is unlikely that the public would be so co-operative about lockdown as we were, at least until the Cummings scandal.

Surely the whole point of lockdown was to hinder the spread of infection, thus lowering the R number - the rate of its spreading.
Having done that, we shouldn't be too hasty about getting unlocked again, imo.

If the R is 0.5, it means that, on average, two people will infect one person. One person transmits the infection, while the other one is isolated quickly enough not to pass on the infection.

fevertree

"If the R remains below 1, that means fewer than one person is being infected "... how does that work, does half a person get infected?

Viruses don't behave in the same way as bacteria.

They're not alive and need a host. In the case of coronavirus, the host is ACE2.

If people were strict about social distancing, it would not be able to spread.

I agree with you rockgran.

I don't think the virus is alive as such -it is more like a poison. It becomes active when it has a host. Without a host it decays. If we could stop passing it around it might just disappear.

That's what I was thinking MawB.
The virus is a living creature, looking for means to reproduce.
If we deprive it of means to live it will die - or mutate and adapt to other means of survival. God forbid.
I think most of us underestimate the implications.
Look what has happened to the resistance of bacteria to antibiotics.
Sorry to be so depressing.

I don’t think there is any actual medical evidence that the virus is weakening . It may be mutating but it could as easily be getting stronger.
It is the spread which makes the difference. Fewer people who are positive infecting even fewer people who in turn infect even fewer people is the way forward.
The virus exists for one purpose - to reproduce itself. No positive cases? >No host for the virus.> Virus dies out.

The problem is that although the R value may be on average, just below 1, it varies in different parts of the country. In some regions it is certainly still above 1 and so it is very dangerous for the lockdown to be relaxed everywhere right now.

I'm afraid I'm rather pessimistic on this, I believe the R value is low because of the effects of lockdown. Would like to believe it was because of the virus losing its power but I very much doubt it, not yet anyway.

So less than one, it could either be because of the effects of lockdown, or the virus is losing its power?
or other things.

If the R remains below 1 then it means that each infected person is passing the disease onto fewer than one person which is good.

If the R figure were 2, the number of infections would be 4, then 8, then 16, then 32. Doubling up to high figures very quickly.

I think it means the reproduction number and is a way of rating a disease's ability to spread.

It's the number of people that one infected person will pass the virus on to, on average. So if it is over 1 the virus is still spreading and if it's less than 1 it's slowing down.