15 May Modeling in France and UK - Kawaski syndrome - diagnosis and exit

1. Interesting modeling from France (see Science paper):
   • % of total population infected = 4.4 %
   • of infected hospitalized = 3.6 %
   • IFR = 0.7 %:  of infected die (but 10 % in 80+)
   • Effect lockdown: decrease of R0 from 2.9 to 0.67 

See very nice figure p. 5 and 6

Caveats:            

- Not based on serology, but rather an extrapolation of Diamond Princess cruise ship.

- 9000 deaths in retirement homes were excluded

A modeling exercise in UK (paper too big, will be send in a second mail) finds a similar reduction in R0 2.8 before lockdown to 0.8 after 1 month.  However, they presume that unreported cases could by 200 times higher than reported ones and come up with a figure of 29 % of the population, already infected!!

2. Epidemics of Kawasaki-like syndrome in children (London, Bergamo, New York….) https://www.bbc.com/news/health-52648557

Definition: Kawasaki disease is an acute and usually self-limiting vasculitis of the medium caliber vessels, which almost exclusively affects children

Symptoms: unrelenting fever (38–40°C), rash, conjunctivitis, peripheral oedema, and generalized extremity pain with significant gastrointestinal symptoms, followed by shock.

Cause: unknown, but infectious trigger suspected to elicit a hyperinflammation, macrophage

activation syndrome (MAS),…. In genetically predisposed individuals…

Treatment: hemodynamic support, intravenous Ig, aspirin, corticosteroids

Prognosis: most infants survive, but death possible.

Data from London: Children originally negative for SARS-CoV-2 PCR, but many exposed and l              ater positive for SARS-CoV-2 antibodies.  6/8 were Afro-Caraibian; 5/8 boys

Bergamo: 7/10 boys, 8/10 antibodies to SARS-CoV-2; no data on ethnicity.

Nice comparison of Kawasaki before end during COVID:

1. Massive increase in incidence (30X)
2. Late onset of the disease compared with the primary infection, due to the host immune response.
3. Older, had respiratory and gastrointestinal involvement, meningeal signs, and signs of cardiovascular involvement
4. Lymphopenia, thrombocytopenia, and increased ferritin, as well as markers of myocarditis.
5. More resistant to IV immunoglobulin treatment

3. Diagnosis and contact tracing. See review and editorial

The review discusses the various tests and provides a good definition of what is considered a “contact”.  A contact is a person who experienced any one of the following exposures during the 2 days before and the 14 days after the onset of symptoms of a probable or confirmed case:

1. Face-to-face contact with a probable or confirmed case within 1 m and for more than 15 min.

2. Direct physical contact with a probable or confirmed case.

3. Direct care for a patient with probable or confirmed COVID-19 disease without using proper personal protective equipment.

For confirmed asymptomatic cases, the period of contact is measured as the 2 days before through the 14 days after the date on which the sample was taken, which led to confirmation.

The Editorial stresses the importance of massive testing: they propose 2 % of population daily, with preference for high risk (HCW, elderly…). For Belgium that would mean 230,000 tests per day ! Only possible if easier sampling (e.g. saliva ?), more rapid testing (e.g. CRISPR-Cas?) and pooling is applied.

They also point to the limitations of the antibody tests and plead for the application of Apps in contact tracing…..?

Best wishes,

Guido