This calculator attempts to estimate the true proportion of a population that have immunity against COVID-19. Given just the natural infection rate and vaccination rate, one can estimate the total population immunity against COVID-19 in any region.

Traditional immunity estimates only look at a single metric: vaccination rate. But there are two main issues with this:

Not all vaccinated individuals are protected (since vaccine efficacy is not 100%) They do not take into account acquired immunity from those who have previously been infected with COVID-19. This calculator attempts to correct for these two major issues to give a more accurate representation of the total population immunity. for the spreadsheet behind the calculators (including raw formulas). ## Inputs

Natural infection rate (% already infected): % (US reference: ~30-40%) Total population vaccination rate (with 1+ dose): % (US reference: ~55%) Vaccination rate among previously infected individuals (should be slightly lower than the total vaccination rate): % (US reference: ~45%) ## Total Population Immunity:

Note: Even if population immunity is at or near herd immunity, local outbreaks are still possible (and even likely given new variants). Even if protection is not 100%, vaccines are near 100% effective at protecting against hospitalizations & deaths.

## Efficacy Constants

These are best estimates based on the latest research, taking into account the variants.

Average vaccine efficacy: Average natural immunity efficacy: Average vaccine + natural immunity efficacy: