% | of unvaccinated people will catch Covid |

% | of everyone will end up getting Covid^{*} |

% | of vaccinated people will get breakthrough Covid |

^{*}not including people who get effectively vaccinated after they get sick

Final Total Immune | % |

Reached Herd Immunity? | |

Immune because of Vaccination | % |

Immune because they got sick | % |

Chance of getting Sick if Unvaccinated | % |

Chance of getting sick if Vaccinated | % |

This page makes the assumption that Covid will continue spreading until we reach herd immunity. This is a reasonable assumption since so far we've seen that if R gets below 1 we relax restrictions until Covid starts spreading again (i.e. R > 1). This will keep happening until R CAN'T be above 1 because we've reached herd immunity.

The herd immunity threshold is related to the reproduction rate:

Immunne threshold = 1 - 1/RThe delta variant is currently estimated at R=7 or 8. Each variant has a been a bit better at spreading, so we may well find ourselves dealing with a higher R before this is over._{0}

The percentage of folks who are immune is

Immune = (%vax * vaxEffectivness) + %sick - %doubleSafePeople who get sick AND then are vaccinated would count twice if we didn't account for them. In the calculation above I DON'T include these people in the "Immune because they got sick" bucket (unless they also fall in the vaccine was ineffective bucket).

The percentage that get sick is

1 - Immunity Thresholdand the total vulnerable is

(1 - vaccinated) + (1 - vaxEffectiveness) * vaccinatedSo the final equation for how likely you are to get sick if unvaccinated

P(sick if unvaxed) = ((1 - 1/R_{0}) - (vax%*vaxEff))/(1 - (vax%*vaxEff))

As you can see from playing around with the sliders, getting to a
high vaccination rate is very important if we want to prevent a lot
of people from getting sick. We also need to quickly stop Covid so
we don't generate new variants with higher R_{0}.