(1/12) The #CovidToes mystery deepens again.
It looks like they are caused by #SARSCoV2 after all, but people have been looking with the wrong test.
It seems pretty conclusive now that #COVID19 cases in children are being missed.
A short thread...
It looks like they are caused by #SARSCoV2 after all, but people have been looking with the wrong test.
It seems pretty conclusive now that #COVID19 cases in children are being missed.
A short thread...
(2/12) First, the paper which started it all.
Doctors in Italy noticed "an epidemic of acroischemic lesions of some toes and fingers in asymptomatic children and adolescents", at the height of the epidemic but weren’t able to do testing.
Doctors in Italy noticed "an epidemic of acroischemic lesions of some toes and fingers in asymptomatic children and adolescents", at the height of the epidemic but weren’t able to do testing.
(3/12) Subsequent research found that at least some children with #CovidToes test positive (by RT-PCR) for #SARSCoV2.
This suggested that the phenomenon might be a way to spot some of the children who might be asymptomatic carriers.
This suggested that the phenomenon might be a way to spot some of the children who might be asymptomatic carriers.
(4/12) But larger studies from Spain and Belgium suggested that #CovidToes might just be a coincidence.
These children were negative by RT-PCR and serology in Spain, and negative by RT-PCR in Belgium.
Biopsies were negative by RT-PCR in Belgium, too.
These children were negative by RT-PCR and serology in Spain, and negative by RT-PCR in Belgium.
Biopsies were negative by RT-PCR in Belgium, too.
(5/12) At this point, I wasn't sure. Maybe it was just coincidence. If you go looking for something, you might start finding unrelated things just by chance. Maybe this phenomenon could be explained by behavioural and environmental factors associated with the pandemic.
(6/12) But what happens with an alternative testing method?
In this case series of 7 children aged 11-17 years, all who were tested for #SARSCoV2 by RT-PCR (n=6) were negative. But monoclonal antibody tests of biopsies were positive for all 7 children.
onlinelibrary.wiley.com/doi/full/10.11…
In this case series of 7 children aged 11-17 years, all who were tested for #SARSCoV2 by RT-PCR (n=6) were negative. But monoclonal antibody tests of biopsies were positive for all 7 children.
onlinelibrary.wiley.com/doi/full/10.11…
(7/12) The biopsy from one child was examined with an electron microscope, and virus-like particles were found.
(8/12) The authors concluded: "the presence of SARS‐CoV‐2 in the endothelium of dermal vessels in skin biopsies of children and adolescents with acute chilblains confirms that these lesions are a manifestation of COVID‐19."
(9/12) A similar case was just reported in an 81-year-old woman with a widespread rash.
She tested negative for #SARSCoV2 by RT-PCR and serology (the latter performed 6 weeks later), but biopsy of the lesions was positive (by RT-PCR).
thelancet.com/journals/lance…
She tested negative for #SARSCoV2 by RT-PCR and serology (the latter performed 6 weeks later), but biopsy of the lesions was positive (by RT-PCR).
thelancet.com/journals/lance…
(10/12) This suggests a couple of things.
First, #CovidToes probably is a symptom of #COVID19 in most cases. We just haven’t been doing the right tests.
Second, some people (particularly children) do not seem to test positive for #COVID19 and may not produce antibodies.
First, #CovidToes probably is a symptom of #COVID19 in most cases. We just haven’t been doing the right tests.
Second, some people (particularly children) do not seem to test positive for #COVID19 and may not produce antibodies.
(11/12) False negatives in the case of nasopharyngeal swabs could be caused by poor swab technique. I’ve commented on how children might not be properly tested before.
(12/12) The lack of antibodies is more interesting, and needs urgent research.
There’s a lot more to the immune system than antibodies, but it does raise questions about whether some people develop sufficient immunity after infection.
There’s a lot more to the immune system than antibodies, but it does raise questions about whether some people develop sufficient immunity after infection.
