Living on Plague Island

On Thursday morning I received an email from the UK Office for National Statistics explaining that following on from the pausing of the world respected COVID-19 Infection Survey, they are ‘changing the survey’. This in effect is a significant scaling down and the letter went on to request that previous participants like myself continue to be part of the sample but with will be no financial reward for doing so.

I could not quite believe my eyes so I turned to the ONS website and, sure enough brief details of the new Covid-19 and respiratory Infections survey is all laid out in black and white.

The previous survey involved a monthly PCR swab test to measure COVID prevalence and a finger prick test to measure anti bodies as well as an on-line questionnaire that covered behaviours, wearing of face masks, health, infections, and prevalence of long covid. The new survey will consist of a 10-15 on-line questionnaire covering: health in general, including any recent symptoms or vaccinations against COVID-19 and flu; how much health has impacted on participants usual activities or use of health services; work, or education. .

No testing is proposed so it is unclear how we will they know if people actually have Covid or not? We will not know whether Covid-19 is actually the culprit, let alone whether a new dangerous variant is at work.

Some people might argue that it is better than nothing and on the face of it I would agree because at least it will, I assume, record lateral flow tests done by participant at their own expense as well as providing a measure of ill health and long Covid. However, this is only possible if the survey continues to be representative of the population.

Unfortunately I don’t think this will be the case in future. Participation in the old survey was rewarded with a £20 voucher every month. ONS want participants to continue to take part in the new survey for nothing – not even a small TY voucher from time to time. My own view is this will lead to a significant drop out rate from the survey resulting in very significant bias. People like myself with a keen interest in the subject will continue to participate but what about people who think Covid is over and were only ever doing it for the money, or people who are so time pressured with multiple jobs and responsibilities who will not regard it as a priority if they are not being rewarded? These are the very people who are most likely to catch and spread Covid and the new survey is in serious danger of failing to pick this up.  

There may well be alternative ways of measuring the prevalence of Covid. Analysis of wastewater is one potential way. Indeed it was wastewater analysis which picked up the prevalence of polio in parts of London in summer 2022 and lead to a vaccination campaign aimed at children. Unfortunately the authorities in England stopped analysing wastewater later in the summer and a key question is would it be worth starting this again and extending it so that we might have good local level data.

Professor Christina Pagel explored the issue very briefly in her presentation to Independent Sage on Friday 28 April 2023. This needs further work but is an interesting one to watch, possibly drawing on experience from the USA where there is a weekly wastewater tracker ….