Latest ONS estimates report previous Covid infection reduces chance of testing positive by 80%, exactly the same as having 3 vaccines and a bigger risk reduction than that given by any other vaccination status …

In most cases, the difference is statistically significant (note where the 95% confidence intervals don’t overlap).

For example, the reduction in risk from previous infection is twice that from AZ vaccine even if given within the past 3 months …

And do those previously infected boost their immunity further by getting vaccinated?

ONS reports that being double vaccinated has no effect on the risk of re-infection …

Note the ONS modelled estimates suggest being double vaccinated still gives some protection from testing positive even after 6 months. Levels of risk reduction are not too far off those implied by the UKHSA Vaccine Surveillance Reports for all ages …

Although ONS results include age as a control, they don't estimate how risk reduction from vaccination varies by age.
UKHSA suggest *adult* infection rates are similar for vaxed & unvaxed, possibly even higher amongst vaccinated depending on which population estimates used ...

Both ONS estimates & the UKHSA Reports have serious implications for policy.

They give an insight into why vax passports have proved so disastrous in Ireland, Germany, Austria etc.

Pretty clear sacking unvaccinated carers & nurses will be similarly ineffective …

In fact, based on the ONS estimates, if you really wanted to minimise infection risk, you would be better off placing restrictions on the double vaccinated rather than restricting the unvaccinated but previously infected!
Here is the link for the ONS estimates
(the table on impact of vaccination on reinfection risk is from the 3 Nov edition as this estimate was not updated in the 17 Nov edition).…

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More from @cricketwyvern

17 Nov
It’s hard to think of a policy* which has unravelled so completely & spectacularly as vaccine passports.

They have caused huge harm & division, yet nearly every European country that has introduced them has seen unprecedented increases in Covid infections within a few months …
Note that doesn't mean vax passports have *caused* those increases but, in contrast to what people were promised, they have done absolutely nothing to prevent them.

(that said, it is quite plausible that they do make things marginally worse rather than better) ...
If Government scientific advisors had any integrity, they would be banging on Number 10’s door to demand that vaccine passports are ruled out for England under any circumstances …
Read 5 tweets
11 Nov
Hard to think of a better argument against England’s *Plan B* than Ireland’s situation.
They have had vax passports for months, v high vax rates & never-ending mask laws.
This has done nothing to stop case rates rising hugely over the past few weeks, now well above England* …

Using % positivity to control for higher UK testing makes for an even starker comparison.

Rather than questioning whether vaccine passports & mask laws are actually effective, there are suggestions ROI may go for even stricter vax passports. You really couldn’t make it up ...
As always, cases will come down in Ireland irrespective of whether or not they go for tighter restrictions, just as they have recently in England.

Politicians everywhere seem remarkably resistant to learning lessons from the past 18 months.
Read 4 tweets
11 Nov
The latest @UKHSA Vaccine Surveillance shows 78% of infections in working age adults (18-59) occurred in the fully vaccinated.

Estimated take up for this age group is between 70% (using NIMS population estimates) & 81% (using ONS) ...
Remember NIMS probably understates take up overall whilst ONS probably overstates (may be different for some ages).

So at best, vaccinated are currently testing positive at only a slightly lower rate than unvaccinated, but quite possibly higher ...
Remember also that care home workers manage risks to residents by isolating when symptomatic and regular testing.

How on earth can Govt continue to claim that sacking unvaccinated carers makes things safer for residents?
Read 4 tweets
3 Nov
A reminder why there will be little or no benefit on infection from sacking unvaccinated carers.

89% of care workers in elderly care homes are already double vaccinated. Many of remaining 11% will have been previously infected so high level of immunity ……

Even if the small % who are unvaxed & not previously infected have a higher risk of infection, they still take other control measures, e.g. isolating if symptomatic & regular testing. Any marginal additional risk reduction from sacking unvaccinated will be tiny.
But …

whether vaccinated are actually at less risk of getting infected unclear. We know there is significant waning of effectiveness against infection. Results vary, but some studies conclude VE goes to zero after as little as 4 months for AZ, 7 for Pfizer ……
Read 6 tweets
27 Oct
About this article by @whippletom on HSA surveillance data:
Using the NIMS population may underestimate unvaccinated case rates, but the data still raise serious questions about real world vaccine effectiveness which need investigating not dismissing ……

If we look at age 18-59 (most affected by vaccine mandates), HSA data suggest vaccinated case rate is 58% higher than unvaccinated.

Using the alternative ONS population estimates, rate amongst vaccinated is lower but only by 27%.
The true value will be somewhere in between …

On the face of it, those data are devastating for the case for vaccine mandates.

Rather than criticising @UKHSA for publishing data, far better to try to work out what is going on.

And rather than lobbying for the info to be suppressed, why not push for even more data? …
Read 5 tweets
22 Oct
The latest Public Health England Vaccine Surveillance report is very striking.

They report 80% of adult *cases* in past 4 weeks were fully vaccinated, up from 56% in 9 Sept report.

That doesn’t necessarily mean vaccinated are testing positive at a higher *rate* ...

PHE report adult rates are 40% higher amongst vaccinated overall: higher for all ages >29 & more than double for 40-79 year olds.

But PHE use NIMS population estimates which probably overestimate population meaning PHE unvaccinated case rate may be too low ...

The alternative is ONS population which has the opposite problem (i.e. unvaccinated rates using this may be too high). The true rate is probably somewhere in between.

Here are the case rates & implied vaccine effectiveness (VE) using NIMS & ONS population denominators …
Read 13 tweets

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