Israel explained:

1.7M vaccinated (20% of pop.)

>70% of all 60+ years old

Currently a major surge, but we project a plateau in critically ill in a week

Despite all this, Israel tightened its 3rd lockdown today

A thread on why this was the right decision to make now

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In 1-2 weeks, we expect a plateau in the critically ill due to:

1. Effect of the less strict lockdown imposed 10 days ago

2. Start of the vaccines effect

3. Striking similarity in critically ill rise in the 2nd and 3rd lockdowns. If a rerun, then plateau is a few days away

There are early signs for our projection of a plateau in the coming 1-2 weeks, since the Arab sector has already plateaued, and in the other sectors despite a >60% weekly rise in cases in children, 60+ rose only 10%

May also be the first effects of the vaccines. Too early to say

However, in the background of all this, the UK variant B.1.1.7 is here and spreading

Current estimates are for ~5-10% prevalence, and even at 5% this means dominance in ~4 weeks and ~20K daily cases in ~6 weeks

Look at the outbreak in the orthodox

16-fold increase in cases in 4 weeks. Doubling every week for 4 weeks, from 100 to 1600 daily cases per million

Such rapid growth was never seen here and is likely partly due to the UK variant, estimated to be ~20% prevalence in the orthodox

We modeled two scenarios:

1. Removing the lockdown next week
2. Extending the lockdown next week

We took vaccine pace and effect into account, and model each patient's trajectory including hospitalizations and deaths

Great work by my students @H_Rossman @tomer1812

The model outcomes left no choice. With a 5% prevalence for the UK variant, and even when assuming only a 50% rise in infectiousness and an R of 1, the rise in cases, critically ill, and the death toll were overwhelmingly more, outpacing even the rapid vaccination rate of Israel

Two additional weeks of lockdown combined with rapid vaccination allow a much more manageable response to the UK variant

What was striking is that the difference between extending and removing the lockdown next week was not just quantitative but qualitative:

Removing the lockdown next week results in a short term plateau but a major surge afterwards that extends to March

Extending the lockdown suppresses the UK variant and these extra weeks, when combined with rapid vaccination, allows the suppression of the surge in critically ill

Much is unknown, but these differences left no choice. A 50% increase in infectiousness is just all too powerful