On 18th March, Johnson said that 'a single dose of either Pfizer or AstraZeneca vaccine provides a 60 percent prevention from Covid-19 [he didn't specify which variant, not sure if that makes a difference] and that it reduces hospitalisation by 80 percent, as well as death by 85 percent'.
What did the PM say in his speech tonight, Thursday, March 18?
Two questions:
2. If we're 60% protected against contracting the virus, but the virus is now 50-70% more contagious than this time last year, aren't we back where we were last April in terms of likely spread? R seems to have risen to around 1 in England at the top end of the estimate, now.
Thanks if you can clarify any of this. Oh, and I don't want to know it's unimportant etc, just clarification on the stats.
Confused of Cardiff.
Your 2nd question
Although the Kent variant is more contagious and has a higher mortality rate especially for the young. Most data indicates that the current vaccines are equally effective at preventing serious infection from it as they did for the early variants.
So simple answer is , we are in a much better position than a year ago. A US study indicates that the AZ vaccine, after 3 weeks is close to 100% effective at preventing death and serous illness - that is way higher than the PMs March claim. Also UK data indicates that where there have been deaths and serous cases post vaccine, all the cases were from people with symptoms in the first week of taking the vaccine. They were either pre-infected, infected at the centre or shortly afterwards. Both AZ and Pfizer seem to be about as effective against the Kent variant as the previous strains of COVID.
A recent study in South Africa indicates the Pfizer vaccine is 80% effective against the SA strain, its probably safe to assume the AZ one will be as it produced anti-bodies against the spike protein as does Pfizer. Lab work had shown Pfizer to produce about 1/8th the antibodies to the SA variant compared to the normal variants, however the vaccines are so effective at producing antibodies that this lower number seems to be sufficient. The AZ vaccine tends to bost the T cells response which should help with immune memory - we will have to wait to see if this is borne out.
I have some experience of the vaccine programme, my company is working on the new variant vaccines. There seem to be several reasons to be optimistic going forward despite the appearance of more infectious variants and the expectation of still more variants.
- The virus mutates relatively slowly, much slower than flu, but faster than measles, so chances are the vaccines will hold up for a few more months by which time cases will be lower and the WHO etc will be able to focus on countries like Brazil where there are serous outbreaks
- Secondly new variant vaccines would be rolled out quite quickly. The mRNA technology is relatively quick to modify.
- We now know that vaccines are effective, 12 months ago its was an educated gamble - UK government put £13bn into the vaccine programme not knowing what would work, now the whole world industry is expanding rapidly. Within the next 12 months we will have global capacity to rapidly vaccinate the world population, which means we will get on top of the virus. At present there is not enough supply, that will change in a few months, the US and EU will have surplus supply and be exporting to the developing world. Once that happens new variants wont be produced so quickly and in such numbers.
- This was a new decease to mankind 12 months ago, so we had low natural immunity and it could produce bad symptoms, we know how to teat is better, we will carry residual immunity from vaccines which should reduce the seriousness of infection (CF Spanish flue) and we have medical treatments that are effective in reducing complications. We have better isolation practices and more available PPE
- we have effective assays to do test and trace at scale so can more effectively quarantine those with new variants and hence not to need the sledgehammer of a national lockdown so often if at all - we may see more draconian approaches to quarantine in the UK if other European countries find it effective as time goes on.
- even after lockdown has ended, we can still practice social distancing and continue to take sensible precautions until the disease is under control
So for all these reason we are in a much better place than 12 months ago, let the vaccine programme roll out and we should start to get on top of the disease. It will remain for a few years, but it should be consolable. There is a small chance that a variant will totally escape the vaccines, especially as that will be the evolutionary driver for the virus, but that worry seems a low probability, does seem to be the medical establishments biggest worry.