Starting Tuesday, Saint Agnes Medical Center and Valley Children's Hospital employees must be vaccinated against COVID-19.
Two-thousand nine-hundred employees at Saint Agnes need to make sure they're vaccinated.
Officials say exemptions are available for those with religious or health reasons, but they must be formally requested and approved.
At Valley Children's, vaccinations are required for all staff, physicians, vendors and those conducting business in the hospital.
Kaiser Permanente has a target date of September 30 for all its employees to be fully vaccinated.
Action News spoke with their senior vice president last month about the move.
"Our hope is that our employees who have not yet been vaccinated, as they are understanding what is happening with the delta variant, as they are seeing our hospitals fill up again, as we are preparing for our fourth surge," said Michelle Gaskill-Hames.
As the highly contagious delta variant spreads in the Central Valley and across the U.S., health officials and medical staff are struggling to keep up with the surge in cases, especially among those unvaccinated.