Scotland where data from care home residents and 85+ were vaxxed 1st. Follow up time after 5 weeks means age will confound VE. With few absolute events adjustment for age becomes statistically underpowered (and doesn't capture full care home risk). Hence wide confidence interval
Also interesting to think about vax tech.
Oxford uses chimp adenovirus vector. Although engineered not to replicate, it's tough and can persist for weeks-months before cleared. Continuing to stimulate immune response by causing Sars-Cov2 spike protein production.
Pfizer however is a piece of mRNA in fatty bubble. It can be cleared much quicker by body in days. The actual stimulation phase may last <1 week. Completed immune response/maturation will continue for over a month tho.
But cf Oxford stimulates AND matures immunity for months.
Expecting increasing efficacy trend to be stronger in Oxford vax.
(But both showing trend upto 4-6 weeks especially older pop where immune response slower)
Dream of 100% Oxford hosp VE remains alive after 6 week fwiw (low confidence :p)
Some seasonality expected for resp viruses, hard to say how much. England had unique circumstance Feb 7-13th.
- week long cold snap across country of similar magnitude
- no change in restrictions
- no increase in daily mobility
1/
Due to variables being reasonably controlled we can estimate how temperature may affect general transmission dynamics.
Note Seasonality: viruses transmit at ALL times of year but climate affects biology and behaviour which impacts on how much transmission occurs.
2/
Cases by specimen date in England showed a marked deceleration in the rate of decline the week after the cold period. From more than -5% per day to less than -2%.
(daily change adjusted for day of the week effect in testing)
But Ab tires don't increase until 2nd dose for Pfizer, especially in the older age cohort who are the priority vaccine targets. How much protection are we giving them?👇
The 86% is a pooled estimate of all ages with younger population dominating.