The Sonoma County Health Officer is recommending that employers should require their workers to have proof of a coronavirus booster shot. Doctor Sundari Mase issued the recommendation yesterday. Dr. Mase also said that employers should require unvaccinated and unboosted employees to wear surgical masks in indoor workplace settings. County employees may soon have to abide by these new guidelines, as the Board of Supervisors intends to adopt the booster requirement for all employees.