The Fresno County Department of Public Health says there are currently 22 known cases of the variant in the county.
"The rapid spread of the Delta variant is concerning," says Dr. Rais Vohra, Interim Health Officer.
While the state no longer requires fully vaccinated residents to wear face masks, local health officials are "strongly recommending" all people still wear face masks indoors regardless of vaccination status.
"This Delta variant is spreading fastest in areas with low vaccination rates," says Joe Prado, Interim Assistant Director. "Vaccines provide excellent protection against the Delta variant and other COVID-19 strains."
Thursday afternoon, the Los Angeles County Department of Public Health re-implemented a mandate requiring residents to wear masks while indoors, regardless of their vaccination status.
RELATED: Mask mandate: New LA County health order requires face coverings indoors as COVID cases spike
ABC30 reached out to other local counties for responses.
Phylisha Chaidez, Madera County Public Health Dept. Community Health and Wellness Assistant: "At this time, we are not modifying or developing our own masking guidance outside of CDPH. We encourage everyone to get vaccinated to protect themselves and their family. Those who are not vaccinated need to continue to wear a mask, and those who are vaccinated may continue to do so."
Amalia Madrigal Hernandez: "At this moment we are following the State's guidance."
Eric Sergienko: "We are watching the increase in cases and hospitalizations in the Bay Area and Southern California. We have had one confirmed case of the Delta variant in Mariposa County and likely have more. Based on our current prevalence, we don't recommend or require masking for persons who are already fully vaccinated. That said, if we see increasing cases in the region, we would likely move in that direction. And pending that need, if fully vaccinated persons want to wear masks, we support that action. Bottomline, however, is that there would be a greater benefit if persons who have not been fully vaccinated would wear masks while indoors and get vaccinated.
Carrie E Monteiro Public Information Officer, Tulare County HHSA: "At this time, Tulare County Public Health is following the California State Health Officer's Order and the State's current guidance and recommendations on masking and face coverings. We are concerned about the Delta variant and strongly urge everyone to get vaccinated as soon as possible to minimize and slow the spread of COVID-19 as the vaccine is proven to provide strong protection against the emerging variants."