Thread by @chrischirp

THREAD on latest PHE report on vaccine waning (and need for boosters):

Important new report from @PHE_uk on vaccine waning by age and at risk status - basically yes there's waning, but still good protection against severe disease for most people. 1/9

Firstly, protection against symptomatic infection starts waning against Delta (orange) about 10 weeks after 2nd dose (70 days).

Waning with both vax, but AZ starts and ends with lower protection. 2/9

Protection against hospitalisation is much higher and stays stronger - particularly for Pfizer. Some waning in AZ from about 20 weeks (5 months/140 days) after dose 2 but even so efficacy remains at about 80% for AZ after 20 weeks 3/9

Looking again at protection against hospitalisation (severe disease) by age, protection a little lower in over 65s compared to 40-64 yr olds - and mainly for AZ.

Very similar levels of effectiveness in both age groups for Pfizer and minimal waning. 4/9

For people aged 40-64 who received AZ, waning is mainly coming from those in a clinical risk group. Little waning in either category for Pfizer in that age group.
(Note all these charts are effectiveness against hospitalisation, not infection). 5/9

In older adults (65+), there is evident waning for Pfizer after about 20 weeks if they are clinically extremely vulnerable. For AZ, there is waning in both groups - wide confidence intervals since many adults in these categories received Pfizer. 6/9

Finally, for over 80s (who mostly received Pfizer), there is clear waning in efficacy against hospitalisation from about 10 weeks after 2nd dose - although it still remains good at 70% protection. 7/9

So I guess the boosters are addressing mainly the waning against severe disease in over 50s and those in a clinical risk group - particularly those who received AZ vaccine.
Plus it should come with added benefit of increasing protection against infection & transmission. 8/9

Finally - protection in adults 40-65 who are not in a clinical risk group remains *very* high (almost 100%) for both vaccines out to 20 weeks - although most 40-somethings had their second dose only 8-12 weeks ago. 9/9

PHE report here:
assets.publishing.service.gov.uk/government/upl…

PS we seem to be seeing less waning with Pfizer than Israel has - perhaps because of the longer dose interval (8-12 weeks vs 3 weeks)?