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expert reaction to latest data from the ONS COVID-19 Infection Survey looking at antibody and vaccination data for the UK

The Office for National Statistics (ONS) have released the latest data from their COVID-19 Infection Survey, including antibody and vaccination data for the UK.


Prof Kevin McConway, Emeritus Professor of Applied Statistics, The Open University, said:

“The latest fortnightly ONS bulletin on antibody and vaccination levels in the UK community population, based on the ONS Covid-19 Infection Survey (CIS), takes the data up to 29 August. The results generally show either little change from the previous release, or a continuation of previous trends or of patterns seen in other data. On antibodies against the virus that causes Covid-19, it’s still true that the overall estimated percentage of people testing positive for antibodies remains high across the UK, with over 9 in 10 adults estimated to test positive in each of the four UK countries. The overall level hasn’t changed much since the last release. There have been some increases in the percentage testing positive in the youngest age groups included – that could be from new vaccinations or new infections, because the antibody test results reported here don’t distinguish between the two. There have also been some falls in the percentage testing positive in the oldest age groups. That might well be because of so-called ‘waning’ of antibodies, though ONS make it clear that antibody positivity isn’t the only aspect of immunity, and the falls are in any case rather small, so that the great majority remain antibody positive even in the oldest groups.

“The data on vaccination levels are presented in this report, according to ONS, to allow easy comparison with the antibody figures, and data on vaccinations are available elsewhere. But the charts in this report do make the picture clear. In particular they show continuing rises in the percentage vaccinated in the two youngest age groups, 16-24 and 25-34. (In older groups the levels were already very high anyway.)  For the 16-24 group, there has been a fast increase in the percentage having received at least one dose – that must have a lot to do with the recent availability of jabs to young people aged 16 and 17. The percentage in this age group who are double jabbed is going up pretty fast too, at between a third and a half of the age group in the different UK countries, though it’s still a lot smaller than in older age groups. Those increases aren’t yet clearly showing up in the form of really fast increases in the antibody figures, but that’s probably just because it takes a few weeks after vaccination for antibodies to become detectable. For the 25-34 group, the percentage who have received at least one dose was already high in the previous release, but this time it’s clear that the percentage fully vaccinated in this age group was continuing to rise fast. All good news.

“We’d know more about what’s going on if ONS had started publishing results that distinguish between antibodies arising from vaccinations and antibodies arising from vaccination. They have been measuring two types of antibody levels in the CIS samples since March, but no results have appeared yet. I asked ONS about this, and was told that they are doing exploratory analysis on this, which will be reported on later this year. I’d certainly like to know some results.”


All our previous output on this subject can be seen at this weblink:


Declared interests

Prof Kevin McConway: “I am a Trustee of the SMC and a member of its Advisory Committee.  I am also a member of the Public Data Advisory Group, which provides expert advice to the Cabinet Office on aspects of public understanding of data during the pandemic.  My quote above is in my capacity as an independent professional statistician.”

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