The CEO of AstraZeneca says it was partly that their vaccination programme was several months in arrears, and so they weren't able to open up in mid-summer. Now they are stuck with a winter wave of delta.
Our scientists think we're unlikely to see a huge wave due to an advanced booster programme, use of AZ which has more staying power and letting the vaccination programme combat delta over the last 4-5 months. Hospitalisation rates are low for people wh have been vaccinated..