It’s everywhere nearly. The UK variant (called “Alpha”) has become the dominant strain (see that graph far below). But now the Indian V2 variant (the Delta strain) is taking over from the UK strain. It is rapidly spreading in Russia, Bangladesh and Portugal.
The Nextstrain country comparison site shows which variants are most common — prevalence of the strain — not the absolute numbers. There are “only” 5,000 new cases a day in the UK at the moment (far down from the peak of 60,000 cases a day). But they are increasingly the Indian variant.
In the USA there are only 12,000 new cases a day, and only a hint of the Indian Delta variant.
The rate of increase is easier to see if the other variants are deselected.
There are some ominous looking trajectories there.
It’s the slope of the trend change in the Delta variant that matters. (The last week of data in India is probably an anomaly.)
The Indian Delta variant has also spread to China, which is doing what it always does, mass testing and lockdowns. The Chinese presumably know more about the design of Covid than anyone, and they are not aiming for herd immunity..
The rate of spread or R0 of the Delta strain is around 5, meaning one person infects five others on average. This is twice as fast as the original Covid spread was in 2020. It is quite a different disease. It means that once it gets loose in the community, we’d need stricter restrictions to reduce the R0 to 1 or less. — the point where the number of cases starts to shrink. It will be much harder to put back in its box.
Hotel quarantine has to keep up with the variants
The more easily these viruses spread, the more stringent the hotel quarantines will have to be. Victoria, Australia was probably lucky (in one sense) that the newest hotel breach occurred at the same time as restrictions were already running. So one lockdown has slowed both escaped strains. Like a two-for-one deal. Hopefully poor suffering Victorians will get more freedom back on Friday.
Given the astronomical costs and pain of another lockdown — we could throw a billion dollars at building new facilities for quarantine and still come out far ahead. China built hospitals in ten days. Can’t we put mining demountables or Glam-camping type tents in a hot dry location and prevent the breaches?
Coronavirus: Double-strength Delta strain to dominate
Natasha Robinson, The Australian
The Delta variant, also known as B.1.617.2, is about 50 per cent more infectious than the Alpha strain that first emerged in Britain last year, according to the latest data from Public Health England. The Alpha strain was about 40 per cent more infectious than the original Wuhan strain, making the Delta strain almost twice as infectious as the original wild type of the virus.
The Delta variant emerged in India around October last year and has now spread to 100 countries. It has emerged as the dominant strain of the virus in the UK owing to its increased transmissibility, with 12,431 cases of the Delta variant detected in Britain since the strain first arrived from India in January. Delta variant case numbers rose by 5472 in the week up to June 3, much faster than any of the other variants of concern.
The UK variant took over in most places:
Just to show how fast the UK strain spread, see these graphs and ponder that the Indian variant spreads more easily that this one.
The big (sad) question is whether there be another wave in the UK
I didn’t want to even ask this question. But cases are rising again there up 90% in a week. But three quarters of UK adults have had at least one vaccine dose and at least 5 million have suffered through Covid (and probably a lot more) and have some protection. But its a race – newer variants mean older vaccines don’t work as well. In lab tests, protection (whatever that is defined as) against the Indian strain was only 33% after one dose of the Astra Zenica or Pfizer vaccine which was quite a bit lower than 51% for the old UK variant. It improves after the second jab substantially.
At least in hospitals in the UK, the vaccine seems to be useful, so far:
Three-quarters of cases of the Delta strain in Britain have been among unvaccinated people, with only 3.7 per cent of cases in people who were fully vaccinated.
But the virus will keep mutating, and without a cocktail of drugs to reduce it dramatically, sooner or later a variant will arise that can get around the vaccine defenses. Using antivirals like Ivermectin or Hydroxychloroquine would dramatically slow the mutation rate.
Newer variants are coming. Time to embarrass journalists for not even asking…
June 8, 2021