I'd just like to comment on the frequent claims in the media that all of the vaccines "prevent" severe illness and death. Unfortunately, this is not true. The clinical trials did not have sufficient sample size for any conclusions on this. However real-world data shows that while the risk is significantly reduced, vulnerable people who have been vaccinated are still dying.
Data from Israel
https://www.nejm.org/doi/full/10.1056/NEJMoa2101765
Data from Scotland:
Only prevention of transmission will stop people from dying!
Seems to provide evidence for going with a single dose --- reduction in hospitalisations 95%? I wonder if this will encourage the the UK Westminster Government to further delay second doses i.e. to get more people a first dose.
Still, only sure approach to avoid severe illness/death is not getting the virus!
If you were responsible for the decision @Snow Leopard would this data suggest the optimal time for the second dose is e.g. 28 days -- or is it still not clear?