General Motors has deployed a confidential survey to its employees about vaccination status. GM has required all their U.S. salaried employees to confidentially disclose their vaccination status. The company will be using this information to assess their immunity levels and guide their safety protocols. GM’s CEO said the company is going to use this survey data to decide whether to institute a vaccination mandate.
See "GM surveyed its workers on their vaccination status", Michael Wayland, CNBC, August 27, 2021