Hey Ken. At a talk last night by a functional med/environmental doc, she said that recent research has shown that 21% of the population has MCAS (Mast Cell Activation Syndrome). Apparently, she said, MCAS is finally being recognised by the medical profession. She went on to say that if someone with MCAS gets Covid, they almost always get Long COVID. Can you draw any conclusions between the microbiome and MCAS as you have with other conditions, and maybe relate it to your other research into Long Covid?

The joy of a citizen science site with lots of contributed data is that we can get informal insight. For more information about the probable bacteria involved see Multiple Chemical Sensitivity (MCS) – A Cause Found?

Q: Does 21% of the population has MCAS (Mast Cell Activation Syndrome)?

A: We have 336 samples annotated with MCAS or histamine issues out of 1747 annotated samples. That is 19.2%. Conclusion: We are in agreement with the research.

Q: if someone with MCAS gets COVID, they almost always get Long COVID?

A: This is a bit of a chicken and an egg question. People with CFS/ME gets MCAS. Looking at uploads prior to Long COVID appearing, we actually have 30.5% of all samples with MCS; 16.5% of samples with ME/CFS (104). The incidence of MCAS in this ME/CFS population was 58%.

We have 190 samples annotated with Long COVID but only 13 reporting MCAS. My conclusion is that all of the people she saw with MCAS were borderline ME/CFS or ME/CFS already. A likely correct statement is that someone with ME/CFS and MCAS is likely to get Long COVID. All that COVID is likely to do is to push the person further into the ME/CFS spectrum. We cannot separate Long COVID from ME/CFS.

Doing filtering of people with MCAS without ME/CFS and then Long COVID, we get a 6.4% incident rate. This suggests that MCAS without being comorbid with ME/CFS does not always get Long COVID.