Thread by @dgurdasani1

Rather disappointed by the reporting of what is a heavily flawed study in the media to suggest that long COVID is rare in children. There are many issues with this study that I'm sure long COVID researchers & patients will flag, but here's my analysis🧵
thelancet.com/journals/lanch…

1. Let's look at the context of the study. It's proxy reporting for children by parents through the Zoe symptom tracker. The study acknowledges that those using the app are more likely to be white & higher socio-economic status, both associated with reduced risk of poor outcomes

2. Even among those sampled and found to be PCR positive, only 24% appear to have had information deemed complete enough for analysis. Are those who were deemed to have more complete information logged likely to have been different from everyone using the app? Very possibly.

3. The app relies on parents proxy logging symptoms themselves, with some limited information through direct questions. In fact, the direct question list seems to have been revised in Nov 2020, but for some reason these were not included in analysis.

4. Any long COVID researcher, or person with lived experience looking at the list would immediately see that the list excludes important symptoms that are quite common in those with long COVID including children- particularly neuro-cognitive symptoms.

5. In fact, in a later analysis (not the main analysis) that does look at when broader questions were asked systematically, symptoms like brain fog were found in 6% of younger children and 11% of older children. So common known symptoms with long COVID were not directly assessed.

This is problematic. Any long COVID researcher who has done surveys, and included an 'other' descriptive option for free text knows that symptoms are often underreported unless they are asked for specifically.

6. A key limitation of this study is the lack of understanding of the relapsing and remitting nature of disease which makes me seriously question whether there was adequate patient involvement, because symptoms were deemed to end if there was a more than 1 wk gap between them.

7. There is extensive research now that shows that children (and adults) can have longer asymptomatic periods in the middle, and may even be largely asymptomatic at the start of infection for weeks before later symptoms occur.

8. Even among the few parents that participated in the study many stopped logging symptoms after some time, including those with prolonged symptoms. This was taken to mean symptoms had resolved.

We know from ONS data & long COVID research that significant number of children have symptoms even lasting>1 yr. ONS estimates 9000 children with this currently. Would anyone expect parents to keep logging symptoms on an app for long periods of time with a sick child?

Duration was calculated using this anyway, which will very likely not just underestimate the incidence of long COVID but also the duration. In fact, some of this doesn't even pass basic scrutiny. Neuro-cognitive symptoms have been found the most persistent with long COVID.

This study suggests brain fog symptoms lasted for a median of 1-3 days. Once again, want to stress how relapsing and remitting these symptoms are and any person with lived experience could've really contributed to improving methodology here.

It's no surprise that the study estimates are out of line with the ONS long COVID study - which is nationally representative, asked a wider range of questions, and considered in a better way the relapsing & remitting nature of disease, also engaging with researchers & patients.

I also want to question the characterisation of 'rare'. Even if one believes the results are valid, and 4.4% of cases develop long COVID - let's extrapolate this just from last week-

If one even considers an average 300/100K/wk incidence in under 18s (this rate is >600/100K/wk in 10-19 yr olds), that's 42000 under 18 cases in 1 wk and ~1800 cases of long COVID in a week in children. Is this acceptable? No.

It's vital that long COVID research includes patients, and engages with their real experiences, also to improve the design of the research, so its limitations, and validity can be understood in the context of what we know about this syndrome.

While this study can be deemed exploratory analysis of data that are available, this has not actually designed as an adequate survey or evaluation of long COVID - by not assessing symptoms systematically or accounting for the nature of illness.

Adding to this the high levels of missing data (only 24% participated, and many didn't have complete information - with assumptions of completeness made that are almost certainly not accurate) - and the lack of representativeness brings validity of results into serious question.

Also, parents with children with long COVID, or even in households with long COVID (unsurprisingly there are households with long COVID) are very unlikely to be motivated to report even common symptoms (esp when many are not assessed directly) - for long periods of time.

Surveys of long COVID that have been patient led, or patient informed have worked very hard to get past many of these biases, as far as possible, because without these, it is very hard to quantify the incidence of a syndrome that is relapsing and remitting.

At the very least comparisons with other studies in children would've revealed that many common symptoms weren't even assessed which almost certainly led to underreporting here. The authors themselves have highlighted brain fog- which was common but not included.

I honestly really worry about how these flawed studies that ultimately end up minimising the real experiences of children and parents impact those who struggle with this day-to-day. They have been gaslit extensively, having to fight for their suffering to just be recognised.

They are suffering from a new disease we don't understand or have treatment for. The very least we can do is to design research well to capture their reality, working with them to improve their lives, rather than minimise their experiences, and add to their suffering.