On Vaccinations Programmes and Normality in September 2021

[danieldwilliam]

My thoughts on a vaccine roll out. It will be September 2021 before anything close to normality returns.
(This is one of those blogposts mostly to layout my thinking and force myself to think something through rather than an attempt to Dunning-Krueger myself or to be oracular.)
The noises from vaccine developers seem muted but nobody has reported a massive failure. Certainly not everybody has reported a massive failure yet.
So we are probably 12 months in to an 18 month process.
That would indicate some sort of effective vaccine being announced in January / February with large scale access to it starting in February / March.
My assumptions for the first round of vaccines are
1) they have limited effectiveness compared to our usual experience of vaccines - fewer people than normal will find them protective and the protection will be less than we usually expect.
2) they will have a more time-bounded effectiveness than we are used to - perhaps six months, or 12 months
3) they will have more side-effects than we usually see, making them either unpleasant for some people or unsuitable for some people.
So useful but not a complete answer to the problem.
I'm assuming that production in the West will be geared up to provide vaccines for their entire populations over a 12-month period with say 10% surplus to be shared / exported / donated with the not-West. China will probably sort itself out quicker. Ditto the South East Asian countries with experience of SARS. Other countries will sort themselves out slower.
There will be a second round of vaccines following on about a year from the first round, these will be better in terms of protection, duration and side-effects.
By the time the vaccination programme starts in the UK I think we'll have had about 5% of the population having had the virus in a way that confers some on-going immunity from the point when the vaccine programme starts. (I'm assuming here lots of asymptomatic cases which have not been spotted.) But I'm also assuming enough churn in immunity to keep that number at 5% through out.
Assume the UK has access to a total of 60 million doses over a 12-month period, or 5 million a month, or 7% of the population a month. Then our immunity level starting in March is 5%. It rises to 12% by the end of April. By the end of September 2021, it's a 60%.
In September we start to see people who only gained a short period of immunity from the vaccine they had in March / April / May become less immune. So, our rate of increase in immunity levels slows.
60% - 70% is probably not enough for herd immunity to kick in. I believe a figure of 80% of the population having some form of immunity is required for a disease as contagious as COVID-19. However, it does mean the spread will be slower. This should help Track and Trace operations.
It would also allow those who have been vaccinated to move around with more liberty and for the country to preferentially vaccinate those who are a) at the most risk of dying b) those at the most risk of spreading the disease.
So, we might see a a limited return to normality around September next year.

Comments

[woodpijn.livejournal.com]

How are we 12 months into an 18-month process when the pandemic hasn't been going on for 12 months? Do you mean 6 months into it?

[danieldwilliam]

Maybe not 12 months. I'd misremembered when China had first detected the virus as a bit earlier than December 2019. 10 months in to an 18 month process.