OSHA isn't recognizing natural immunity:
"Based on the best available evidence described above, OSHA concludes that
while some individuals who were infected with SARS-CoV-2 may have significant
protection from subsequent infections, the level of protection afforded by infection may
be significantly impacted by the severity of the infection and some previously infected
individuals may have no future protection at all. In addition, given the limitations of the
studies described above, there is considerable uncertainty as to whether any given
individual is adequately protected against reinfection. Furthermore, the level of
protection, if any, provided by a given person’s SARS-CoV-2 infection cannot be
ascertained based on currently-available testing methods. Therefore, OSHA finds that the
requirements of this ETS are necessary to protect unvaccinated individuals who had prior
SARS-CoV-2 infections from the grave danger from exposure to SARS-CoV-2." (page 78)
https://www.federalregister.gov/public-inspection/2021-23643/covid-19-vaccination-and-testing-emergency-temporary-standard
OSHA isn't recognizing natural immunity: "Based on the best available evidence described above, OSHA concludes that while some individuals who were infected with SARS-CoV-2 may have significant protection from subsequent infections, the level of protection afforded by infection may be significantly impacted by the severity of the infection and some previously infected individuals may have no future protection at all. In addition, given the limitations of the studies described above, there is considerable uncertainty as to whether any given individual is adequately protected against reinfection. Furthermore, the level of protection, if any, provided by a given person’s SARS-CoV-2 infection cannot be ascertained based on currently-available testing methods. Therefore, OSHA finds that the requirements of this ETS are necessary to protect unvaccinated individuals who had prior SARS-CoV-2 infections from the grave danger from exposure to SARS-CoV-2." (page 78) https://www.federalregister.gov/public-inspection/2021-23643/covid-19-vaccination-and-testing-emergency-temporary-standard