Just in:
More than 26.8 million first and 2.1 million second doses have now been given in the UK since December.
www.bbc.co.uk
Friday was a record day for Covid vaccinations in the UK, with a combined 711,156 first and second doses given to members of the public.
It means that half of all UK adults - some 26,853,407 people - have now received a first dose of a vaccine.
Health Secretary Matt Hancock said the latest milestone in the rollout marked a "phenomenal achievement".
Prime Minister Boris Johnson - one of those to receive a first dose on Friday - also hailed the landmark.
This is great news, and shows just how great the capacity is, when the supplies are available.
As for the shortage of supplies of the AZ vaccine from India, it turns out the root cause may be due to a shortage of raw materials from the US:
India is lagging behind in its vaccine target as demand falls.
www.bbc.co.uk
The Serum Institute of India (SII) - which produces Novavax and AstraZeneca vaccines - recently raised concerns about raw material shortages.
The firm said it has also faced difficulties importing cell culture media, single-use tubing and specialised chemicals from the US.
Dr John Campbell has stated that there are suggestions that these vaccine components could have been locally produced in India but can't be, because US companies have not made the information available in the public domain, though I cannot find an original source for this.
And in other news, there is some speculation that the reason the AZ vaccine might not be as effective against the South African variant could be because it is not a prefusion vaccine.
Viruses multiply by dumping their genes into our cells and hijacking our cellular machinery to crank out new virus particles. But first, they need a doorway into our cells. Coronaviruses are studded with spikes, which grab hold of proteins decorating our own cells like
doorknobs. Once attached, the spike undergoes a dramatic transformation, stretching before partially turning inside out to forcefully fuse with our cells.
Scientists believe that
for COVID-19 vaccines to be effective, our immune systems must develop antibodies that prevent this fusion. Such antibodies must target the spike protein in its aptly named prefusion conformation. Unfortunately for vaccine developers, spike proteins are liable to spring from their stubby prefusion shape into their elongated postfusion form on a hair trigger.
Fortuitously, Graham and a former postdoc, Jason McLellan, devised a solution to this problem before the pandemic. Through a bit of structural biology and persistent protein engineering,
McLellan discovered that adding two prolines—the most rigid of the 20 amino acids—to a key joint of a vaccine’s spike protein could stabilize the structure’s prefusion shape. This 2P mutation worked in preclinical studies of Graham and Moderna’s MERS vaccine, so they applied it to Moderna’s COVID-19 vaccine.
blogs.sciencemag.org
2nd question: If I recall correctly, both BioNTech and Moderna modified the spike protein RNA so that the spike protein stays locked in the pre-fusion state. In contrast, again if I recall correctly, the Oxford vaccine uses unmodified RNA. Could this result in the protein flipping to the fusion state, making an immune response less effective to the actual virus?
I understand the Oxford team are working on a version of the vaccine that is modified to target the mutations, such as E484K, which occurred independently in both the Brazil and SA variants, but it's not clear to me whether the modifications to the vaccine include making this specific change or not. If anyone knows the answer to this, I'd be interested to hear it.
That said, the effectiveness of the vaccines against variants which include the E484K mutation, are not diminished when measured against severe disease and hospitalisations; it's just that people are more likely to get mild illness when encountering these variants. However some so-called "experts" are desperately trying to scare people into believing the vaccines are not effective. To be clear: they are only "not effective" when measuring effectiveness against mild illness, but who really cares about that, when the aim is to keep people from being seriously ill?
It does frustrate me that the excellent work of vaccine produces is undermined by simpletons such as Andrew Hayward from Sage:
https://www.bbc.co.uk/news/uk-56467813
"I suppose one of the more worrying things about this resurgence is that in some parts of Europe the South African variant is beginning to creep up to higher levels," he told Times Radio.
He said this variant was of "particular concern" because vaccine effectiveness against it was "quite low".
This is completely false messaging; I'd argue it's anti-vax messaging and is dangerous. The vaccine effectiveness is
NOT low, given the aim of any vaccine is to prevent serious illness, and the vaccines do achieve that!
How can it be that I, as a layperson who has simply listened to various podcasts made by experts, understand this better than someone who is on Sage?! Why are people on Sage allowed to spread a misleading anti-vax message? I find this to be deeply concerning.
On the subject of variants and modifications to vaccines, it is certainly the case that a booster could be made available in the Autumn if required. I am not convinced that it will be required though, as we still have good effectiveness against severe disease even with the variants, but time will tell. I don't think it is anything to be concerned about; we'll do it if we need to do it, but it may be the case that we don't.