1/ We developed & validated an oral fluid assay to measure #SARSCoV2 antibodies. Basically it’s a lollipop stick with a sponge that collects oral fluid (saliva) from around cheeks/gums. Kids can do the test themselves & sample can be posted to the lab 🧵👉 medrxiv.org/content/10.110…
2/ Here’s the technical stuff: We used contemporaneous blood & oral fluid samples from ~2,000 kids & adults taking part in our school studies and developed 3 different oral fluid assays for testing & validating: N-antibody, Spike-antibody & RBD-antibody 👉 medrxiv.org/content/10.110…
3/ The N-protein capture assay was the best candidate, sensitivity 75% (95%CI, 71–79%) specificity 99% (95% CI: 78–99%) when compared with paired serum antibodies, but higher sensitivity in kids (80%, 95% CI: 71–88%) than adults (67%, CI: 60%-74%) 👉 medrxiv.org/content/10.110…
4/ The other oral fluid assays using spike protein and RBD antigens were also 99% specific but lower sensitivity in the target population: 78% (95%CI 68%-86%) for Spike and 53% (95%CI, 43%-64%) for RBD assay 👉 medrxiv.org/content/10.110…
5/ Whilst blood remains the best test for antibodies, oral fluids are great for testing 1,000’s of people for population-based studies, like our school infection survey (SIS). We are also improving the assay to test for the virus itself, multiple antibodies & other viruses /End

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More from @ShamezLadhani

16 Jul
1/ We studied the quality,
quantity and persistence of #SARSCoV2 antibodies in primary school students (6-11 year-olds) compared to staff (adults) over 6 months (until ~7-8 months after their #SARSCoV2 infection)

Here’s what we found (pre-print) 🧵

👉 medrxiv.org/content/10.110…
2/ The proportion of students & staff who had #SARSCoV2 antibodies in back June 2020 was similar:

👉 11.5% (95%CI, 9.4-13.9) & 11.3% (95%CI, 9.2-13.6; p=0.88) students had nucleoprotein & RBD antibodies vs 15.6% (95%CI, 13.7-17.6) & 15.3% (95%CI, 13.4-17.3; p=0.83) staff
3/ Live virus neutralising activity (ability of antibody to kill #SARSCoV2) was detected in 79.8% (71/89) of N antibody & 85.5% (71/83) of RBD antibody positive kids. RBD correlated more strongly with neutralising activity (rs=0.75; p<0.0001) than N antibodies (rs=0.37; p<0.0001)
Read 7 tweets
11 Jul
1/9. In England, #SARSCoV2 infection rates in school-aged kids & #COVID19 outbreaks have both ⬆️ in recent weeks (latest data 4 July) but that does not change the narrative on kids & their role in infection/transmission in school

Here’s why … 🧵

👉 assets.publishing.service.gov.uk/government/upl…
2/9. No one has claimed that kids don’t get infected or don’t transmit #SARSCoV2 to others. But the data suggest that lower risk with kids than adults. Eg. We don’t see two-thirds of staff/students infected in a single outbreak as we do in care homes 👉 thelancet.com/journals/eclin…
3/9. We & others have shown that #SARSCoV2 cases & outbreaks reflect community infection rates. Cases in kids generally follow adults *unless* adults are in lockdown & kids continue to go to school. This happened in Nov/Dec 2020 & Mar/Apr 2021. See👇👇

👉 journalofinfection.com/article/S0163-…
Read 9 tweets
10 Jul
1/5. Mental health of Adolescents in the Pandemic: Long-COVID19 or Long-Pandemic Syndrome? (pre-print, thanks @MaryKRe)

Here’s another case-control study on long covid that measured #SARSCoV2 antibodies in teenagers

Here’s what they found … 🧵

👉 medrxiv.org/content/10.110…
2/5. 1560 kids (median age 15y):
- 188 (12%) seropositive (exposed to #SARSCoV2)
- 1365 (88%) seronegative (never exposed)

If you think this sample size is small, try bleeding 1500 teens!

They were asked the same questions ➡️ responses were near-identical in cases & controls
3/5. The authors did a subgroup analysis & found near-identical responses in teenagers who knew their #SARSCoV2 infection status vs those who didn’t

Yes, small samples size, but not even a signal of any difference in mental health status (see table👇)

👉 medrxiv.org/content/10.110…
Read 5 tweets
9 Jul
1/4 Childhood #COVID19 deaths. This preprint by @RCPCHtweets & @PHE_uk provides critical new information about #SARSCoV2 and kids which we didn’t have until now. Here’s why the small numbers in this paper matter 🧵

👉 researchsquare.com/article/rs-689…
2/4 Death is the most objective outcome & can be accurately measured in countries like England. The results show ~3,000 of 12 million kids died in 1 year & only 61 with #SARSCoV2. Detailed medical record analysis showed only 25 (42%) died *of* #COVID19

👉 researchsquare.com/article/rs-689…
3/4. Of the 25 kids who died of #COVID19, 19/25 (76%) had underlying conditions & of these 15/19 (60%) had a life-limiting condition & mostly with 2 or more medical conditions, esp. severe neurological conditions

👉 25 fatalities = 2 per million kids

Read 4 tweets
9 Jul
1/5 Both Pfizer & AZ vaccines are highly protective against severe #COVID19, especially after 2 doses.

Here’s why it’s better to stick to the same vaccine brand for both #COVID19 vaccine doses even after severe reaction following the 1st dose 🧵

👉 papers.ssrn.com/sol3/papers.cf…
2/5 Compared to 2 doses of the same vaccine brand, mixing Pfizer/AZ vaccines was associated with higher rates of severe reactions & requiring medical attention after the 2nd dose: esp. in younger adults, in women & in those with previous #COVID19 🧵

3/5 Adults who had a severe reaction after their 1st dose of #COVID19 were more likely to have a severe reaction after 2nd dose, whichever vaccine they received, but risk of severe reactions increased if 2 different vaccine (AZ/Pfizer) brands given 🧵

👉 papers.ssrn.com/sol3/papers.cf…
Read 5 tweets
21 Jun
1/ News outlets & people on social media have been misinterpreting data on exposures prior to diagnosis as places where people caught #SARSCoV2 (provided in the @PHE_uk Weekly Reports)

Here’s why .…

👉 news.sky.com/story/covid-19… Image
2/. UK has been in lockdown since Nov. In Mar 2021, only schools reopened ➡️ 9 million children & education staff were out in the community. The figure below shows that a person was attending school prior to testing +ve for #SARSCoV2 - not that they caught #SARSCoV2 in school Image
3/ But as we eased into step 3 of opening lockdown, people were more likely to have visited other venues prior to testing +ve for #SARSCoV2

Here’s the same graph for the latest week reported. Eating out & “other” are now more frequent because restaurants & shops are open 👇 Image
Read 4 tweets

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