I've been projecting UK vaccine roll-out timings on the assumption that we proceed down the age-groups until all adults are offered a dose.

But this is not what we should do.

We should open booking to all 18-39s and run a dual-track system: an AZ arm and a Pfizer + Moderna arm.

The logic for proceeding down the age-groups: 75+ make up the majority of deaths - we did them first.

45-64 represent the majority of the burden on the NHS (ICU admissions) - we did them next.

Now we're into diminishing returns, and focus should shift to disrupting transmission

To get better age-discrimination than above, we can look at the latest ONS survey, and examine antibody levels (dark blue lines) before the vaccination campaign got going. This indicates where the cases were.

Vaccinatating 16-35 year olds gets the biggest bang for your jab.

I estimate 5.6m Pfizer & Moderna doses are sitting UK warehouses today. Some are being used, but most are being held back in anticipation of <30s who may request a non-AZ jab.

And this is true. If we give too many Pfizer doses to the 40+s now, we'll not have enough for <30s.

But vaccines are not going to disrupt anything sitting in a warehouse. And in three weeks we will open indoor hospitality.

The best place to store these doses is in arms.

Open booking to 18-39s, run down stockpiles and get breaks in those transmission chains before mid-May

A few Health Boards are on this already (as always, it's the Welsh ahead of the game). They are operating a version of this dual-track distribution strategy.

I think this should be UK-wide. https://www.leaderlive.co.uk/news/19248654.two-vaccination-streams-running-north-wales-amid-new-covid-19-advice/