• Les maths permettent de toujours bien comprendre cette #pandémie.
    Ici, les maths te disent qu’une #variante + contagieuse de 50%, c’est une bien plus mauvaise nouvelle qu’une variante 50% + mortelle. #covid
    https://twitter.com/AdamJKucharski/status/1343567425107881986

    Why a SARS-CoV-2 variant that’s 50% more transmissible would in general be a much bigger problem than a variant that’s 50% more deadly. A short thread... 1/

    As an example, suppose current R=1.1, infection fatality risk is 0.8%, generation time is 6 days, and 10k people infected (plausible for many European cities recently). So we’d expect 10000 x 1.1^5 x 0.8% = 129 eventual new fatalities after a month of spread... 2/

    What happens if fatality risk increases by 50%? By above, we’d expect 10000 x 1.1^5 x (0.8% x 1.5) = 193 new fatalities. 3/

    Now suppose transmissibility increases by 50%. By above, we’d expect 10000 x (1.1 x 1.5)^5 x 0.8% = 978 eventual new fatalities after a month of spread. 4/

    The above is just an illustrative example, but the key message: an increase in something that grows exponentially (i.e. transmission) can have far more effect than the same proportional increase in something that just scales an outcome (i.e. severity). 5/5