Thread by @Jean__Fisch

Could a different vaccination strategy by 🇧🇪 have a had an impact on the current 3rd wave hitting the country?

Answer: "A little bit, but not structurally. AZ delivering according to its initial planning would have though”

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1/ Is BEL slow at vaccinating? Actually not really: It has put roughly as many jabs into arms as other EU countries

A few countries are ahead but they have structurally more doses (e.g. Denmark, Malta, etc.)

2/ Could 🇧🇪 have better focused its efforts on the vulnerable (>80s)? Clearly, other countries have achieved this better

3/ Why is this? Without a deep look by country, it is hard to tell

However, 🇧🇪 followed a sequential approach
1 Care homes
2 Healthcare
3 >65

Other countries do this in parallel (I did not check all) but there was pressure in 🇧🇪 to have a firm date for healthcare

4/ Could 🇧🇪 have administered more 1st doses? Yes but

With the need to provide the 2d dose 4 wks later, going all out in Jan would have meant Feb was for 2d doses only

So impact is essentially on the vaccination strategy in March

5/ Given the delivery uncertainties on AZ and Moderna, it is impossible to apply a zero stock approach on them (yet)

It can only be on Pfizer, for which we received 700m doses in March

6/ So a more aggressive 1st dose strategy by 🇧🇪 essentially means that it could have jabbed 700k with 1st doses in March instead of 500k (with 200k reserved for second doses)

7/ Lets suppose that all these 200k additional doses would have been for the >80s

The >80s represent 650k in 🇧🇪

So we could have increased the penetration by 30% in this group

8/ The >80s are disproportionally representing deaths and hospitalizations

In 🇧🇪, they represented roughly

50% of deaths
40% of hospitalizations

9/ According to the 🇬🇧, one dose of vaccine gives roughly

85% protection against death
80% against hospitalization

assets.publishing.service.gov.uk/government/upl…

10/ So the impact of a more aggressive 1st dose strategy on the overall risk of death and hospitalization in 🇧🇪 could amount to

Deaths: 30% * 85% * 50% = 13%

Hospitalizations: 30% * 80% * 40% = 10%

11/ So a more aggressive approach on 1st doses could have reduced the risk of death & hospitalization by 10% during 4-5 weeks (One then needs to give the 2d jab)

This is of course great (and 🇧🇪 is applying this now)

It is too small to have any big effect on the 3rd wave

12/ As a reference, the delivery of the doses initially indicated by AZ (70m instead of 25m in Q1) would have had a real impact

➡️generated 1000k more doses for 🇧🇪
➡ (more than) allowed to fully protect all >80s
➡reduce death risk by 50% and hospitalization risk by 40%

13/ In summary

➡️A more aggressive vaccination strategy in
🇧🇪 may have generated a 10% benefit for 4 wks
➡️This benefit would not have had any material impact on the 3rd wave
➡️A delivery by AZ according to its original (NB: indicative) planning would have had a material impact