A large chunk of the news this week has centered on Novak Djokovic’s attempts to remain in Melbourne for the Australian Open. At the core of the controversy is a debate over what constitutes sufficient immunity against Covid-19 infection: Djokovic is not vaccinated against Covid-19 but has been infected within the past six months, which in theory should give him immunity against future illness.
The argument that previous infection with Covid-19 should be considered a substitute for proof of vaccination is a heated one these days as Biden’s vaccine mandate is challenged in numerous courts. I’ve received comments from a number of people arguing that previous Covid-19 infection provides superior immunity to vaccination, and therefore that vaccine mandates are more politically motivated than based in scientific fact. So, what do we know about how levels and duration of immunity from vaccination vs viral infection compare? There are a few important things to know:
If you’ve seen arguments that vaccination provides superior immunity to viral infection or vice versa, both are likely based on credible scientific information. In the past six months, numerous studies comparing chance of infection, severe illness, and hospitalization for vaccinated and previously infected individuals have resulted in impressively conflicting results. For example, a US study across nine states from January to September 2021 found previously infected individuals were 5.5 x more likely to be hospitalized with a new case of Covid-19 than fully…