S.F. exploring potential mandate requiring vaccination proof for entry to indoor restaurants, gyms FacebookTwitterEmail Doorman Jason Voisine checks a patron’s proof of vaccination at the Latin America Club in San Francisco. It is one of many bars and restaurants in the city that are now requiring proof of vaccination before entering.Nick Otto/Special to The Chronicle San Francisco is weighing a mandate that could be similar to one New York City announced on Tuesday requiring people there to show proof of COVID-19 vaccination to enter indoor restaurants, gyms and concerts. “We’re exploring that,” San Francisco Health Director Dr. Grant Colfax said Tuesday at a news event highlighting in-home vaccination options. The city is looking into whether there is need to go beyond its encouragement of businesses that have voluntarily instituted their own requirements that customers show proof of vaccination.