The vaccine deployment in December 2020 signaled a turning point in the COVID-19 pandemic. By the end of May 2021, 40% of the U.S. population was fully vaccinated. But as vaccination rates lagged over the summer, new surges of COVID-19 came, including Delta in the summer of 2021, and now the Omicron variant, which comprises the majority of cases in the U.S.

Researchers around the world have reported that Omicron is more transmissible than Delta, making breakthrough and repeat infections more likely.

The United States as of May 4 reached 996,145 COVID-19-related deaths and 81.5 million COVID-19 cases, according to Johns Hopkins University. Currently, 66.2% of the population is fully vaccinated, and 45.9% of vaccinated people have received booster doses.

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Stacker compiled a list of the counties with highest COVID-19 infection rates in California using data from the U.S. Department of Health & Human Services and vaccination data from Covid Act Now. Counties are ranked by the highest infection rate per 100,000 residents within the week leading up to May 3, 2022. Cumulative cases per 100,000 served as a tiebreaker.

Keep reading to see whether your county ranks among the highest COVID-19 infection rates in your state.

#50. Shasta County, CA

– New cases per 100k in the past week: 28 (50 new cases, +194% change from previous week)
– Cumulative cases per 100k: 20,450 (36,826 total cases)
— 12.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 308 (554 total deaths)
— 35.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 46.5% (83,651 fully vaccinated)

#49. Tehama County, CA

– New cases per 100k in the past week: 29 (19 new cases, +217% change from previous week)
– Cumulative cases per 100k: 22,609 (14,715 total cases)
— 3.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 310 (202 total deaths)
— 36.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 43.0% (27,974 fully vaccinated)

#48. Siskiyou County, CA

– New cases per 100k in the past week: 30 (13 new cases, -13% change from previous week)
– Cumulative cases per 100k: 16,613 (7,233 total cases)
— 28.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 186 (81 total deaths)
— 18.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 49.0% (21,337 fully vaccinated)

#47. San Benito County, CA

– New cases per 100k in the past week: 35 (22 new cases, -46% change from previous week)
– Cumulative cases per 100k: 21,510 (13,510 total cases)
— 7.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 156 (98 total deaths)
— 31.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.3% (45,432 fully vaccinated)

#46. Lake County, CA

– New cases per 100k in the past week: 36 (23 new cases, +10% change from previous week)
– Cumulative cases per 100k: 18,092 (11,649 total cases)
— 22.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 213 (137 total deaths)
— 6.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 54.9% (35,377 fully vaccinated)

#45. Kings County, CA

– New cases per 100k in the past week: 37 (57 new cases, +16% change from previous week)
– Cumulative cases per 100k: 36,143 (55,277 total cases)
— 54.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 292 (447 total deaths)
— 28.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 45.1% (68,964 fully vaccinated)

#44. Madera County, CA

– New cases per 100k in the past week: 38 (60 new cases, +329% change from previous week)
– Cumulative cases per 100k: 27,643 (43,490 total cases)
— 18.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 232 (365 total deaths)
— 2.2% more deaths per 100k residents than California
– Population that is fully vaccinated: 54.5% (85,703 fully vaccinated)

#43. Inyo County, CA

– New cases per 100k in the past week: 39 (7 new cases, -53% change from previous week)
– Cumulative cases per 100k: 25,450 (4,591 total cases)
— 9.1% more cases per 100k residents than California
– Cumulative deaths per 100k: 310 (56 total deaths)
— 36.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 62.5% (11,280 fully vaccinated)

#42. Kern County, CA

– New cases per 100k in the past week: 39 (351 new cases, +92% change from previous week)
– Cumulative cases per 100k: 26,522 (238,749 total cases)
— 13.6% more cases per 100k residents than California
– Cumulative deaths per 100k: 252 (2,265 total deaths)
— 11.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.6% (482,790 fully vaccinated)

#41. Yuba County, CA

– New cases per 100k in the past week: 41 (32 new cases, -16% change from previous week)
– Cumulative cases per 100k: 21,795 (17,146 total cases)
— 6.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 154 (121 total deaths)
— 32.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 49.2% (38,732 fully vaccinated)

#40. Sutter County, CA

– New cases per 100k in the past week: 41 (40 new cases, +135% change from previous week)
– Cumulative cases per 100k: 23,524 (22,811 total cases)
— 0.8% more cases per 100k residents than California
– Cumulative deaths per 100k: 231 (224 total deaths)
— 1.8% more deaths per 100k residents than California
– Population that is fully vaccinated: 60.5% (58,669 fully vaccinated)

#39. Butte County, CA

– New cases per 100k in the past week: 45 (99 new cases, +36% change from previous week)
– Cumulative cases per 100k: 18,207 (39,908 total cases)
— 22.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 191 (418 total deaths)
— 15.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 53.2% (116,693 fully vaccinated)

#38. Merced County, CA

– New cases per 100k in the past week: 46 (129 new cases, -10% change from previous week)
– Cumulative cases per 100k: 25,621 (71,145 total cases)
— 9.8% more cases per 100k residents than California
– Cumulative deaths per 100k: 295 (818 total deaths)
— 30.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.8% (143,904 fully vaccinated)

#37. Stanislaus County, CA

– New cases per 100k in the past week: 50 (277 new cases, +7% change from previous week)
– Cumulative cases per 100k: 24,597 (135,447 total cases)
— 5.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 298 (1,643 total deaths)
— 31.3% more deaths per 100k residents than California
– Population that is fully vaccinated: 57.0% (313,933 fully vaccinated)

#36. Mariposa County, CA

– New cases per 100k in the past week: 52 (9 new cases, -47% change from previous week)
– Cumulative cases per 100k: 15,317 (2,635 total cases)
— 34.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 174 (30 total deaths)
— 23.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 44.9% (7,722 fully vaccinated)

#35. Fresno County, CA

– New cases per 100k in the past week: 56 (563 new cases, -30% change from previous week)
– Cumulative cases per 100k: 25,618 (255,954 total cases)
— 9.8% more cases per 100k residents than California
– Cumulative deaths per 100k: 275 (2,748 total deaths)
— 21.1% more deaths per 100k residents than California
– Population that is fully vaccinated: 61.2% (611,326 fully vaccinated)

#34. Riverside County, CA

– New cases per 100k in the past week: 57 (1,413 new cases, +42% change from previous week)
– Cumulative cases per 100k: 25,193 (622,412 total cases)
— 8.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 261 (6,457 total deaths)
— 15.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 58.7% (1,450,332 fully vaccinated)

#33. Del Norte County, CA

– New cases per 100k in the past week: 58 (16 new cases, -16% change from previous week)
– Cumulative cases per 100k: 21,721 (6,041 total cases)
— 6.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 180 (50 total deaths)
— 20.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 47.8% (13,308 fully vaccinated)

#32. Nevada County, CA

– New cases per 100k in the past week: 60 (60 new cases, +40% change from previous week)
– Cumulative cases per 100k: 17,376 (17,333 total cases)
— 25.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 127 (127 total deaths)
— 44.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 63.2% (62,999 fully vaccinated)

#31. El Dorado County, CA

– New cases per 100k in the past week: 64 (124 new cases, +158% change from previous week)
– Cumulative cases per 100k: 15,653 (30,186 total cases)
— 32.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 109 (210 total deaths)
— 52.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 60.9% (117,363 fully vaccinated)

#30. Plumas County, CA

– New cases per 100k in the past week: 64 (12 new cases, +200% change from previous week)
– Cumulative cases per 100k: 17,605 (3,311 total cases)
— 24.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 69 (13 total deaths)
— 69.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 55.0% (10,337 fully vaccinated)

#29. Placer County, CA

– New cases per 100k in the past week: 65 (260 new cases, +11% change from previous week)
– Cumulative cases per 100k: 17,762 (70,750 total cases)
— 23.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 157 (625 total deaths)
— 30.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.0% (266,863 fully vaccinated)

#28. Orange County, CA

– New cases per 100k in the past week: 74 (2,354 new cases, +33% change from previous week)
– Cumulative cases per 100k: 18,709 (594,132 total cases)
— 19.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 220 (6,998 total deaths)
— 3.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.6% (2,305,143 fully vaccinated)

#27. Ventura County, CA

– New cases per 100k in the past week: 75 (635 new cases, +38% change from previous week)
– Cumulative cases per 100k: 21,757 (184,065 total cases)
— 6.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 176 (1,486 total deaths)
— 22.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.1% (610,066 fully vaccinated)

#26. Calaveras County, CA

– New cases per 100k in the past week: 78 (36 new cases, +64% change from previous week)
– Cumulative cases per 100k: 16,754 (7,691 total cases)
— 28.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 261 (120 total deaths)
— 15.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.5% (24,560 fully vaccinated)

#25. San Joaquin County, CA

– New cases per 100k in the past week: 78 (591 new cases, +98% change from previous week)
– Cumulative cases per 100k: 23,188 (176,728 total cases)
— 0.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 292 (2,225 total deaths)
— 28.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 61.5% (469,001 fully vaccinated)

#24. Amador County, CA

– New cases per 100k in the past week: 80 (32 new cases, +14% change from previous week)
– Cumulative cases per 100k: 23,136 (9,197 total cases)
— 0.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 216 (86 total deaths)
— 4.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 52.5% (20,887 fully vaccinated)

#23. Yolo County, CA

– New cases per 100k in the past week: 91 (200 new cases, -22% change from previous week)
– Cumulative cases per 100k: 18,333 (40,425 total cases)
— 21.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 142 (314 total deaths)
— 37.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 70.5% (155,464 fully vaccinated)

#22. San Luis Obispo County, CA

– New cases per 100k in the past week: 92 (260 new cases, +76% change from previous week)
– Cumulative cases per 100k: 20,106 (56,923 total cases)
— 13.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 168 (477 total deaths)
— 26.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.1% (181,569 fully vaccinated)

#21. Santa Barbara County, CA

– New cases per 100k in the past week: 94 (418 new cases, +12% change from previous week)
– Cumulative cases per 100k: 20,533 (91,679 total cases)
— 12.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 154 (688 total deaths)
— 32.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.2% (308,820 fully vaccinated)

#20. San Bernardino County, CA

– New cases per 100k in the past week: 95 (2,077 new cases, -19% change from previous week)
– Cumulative cases per 100k: 27,240 (593,862 total cases)
— 16.7% more cases per 100k residents than California
– Cumulative deaths per 100k: 330 (7,191 total deaths)
— 45.4% more deaths per 100k residents than California
– Population that is fully vaccinated: 56.9% (1,240,838 fully vaccinated)

#19. Tuolumne County, CA

– New cases per 100k in the past week: 103 (56 new cases, +133% change from previous week)
– Cumulative cases per 100k: 24,391 (13,288 total cases)
— 4.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 332 (181 total deaths)
— 46.3% more deaths per 100k residents than California
– Population that is fully vaccinated: 52.4% (28,566 fully vaccinated)

#18. San Diego County, CA

– New cases per 100k in the past week: 103 (3,451 new cases, +24% change from previous week)
– Cumulative cases per 100k: 24,392 (814,292 total cases)
— 4.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 157 (5,238 total deaths)
— 30.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 80.3% (2,682,311 fully vaccinated)

#17. Mendocino County, CA

– New cases per 100k in the past week: 108 (94 new cases, +62% change from previous week)
– Cumulative cases per 100k: 18,815 (16,322 total cases)
— 19.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 142 (123 total deaths)
— 37.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 68.8% (59,671 fully vaccinated)

#16. Monterey County, CA

– New cases per 100k in the past week: 108 (467 new cases, +74% change from previous week)
– Cumulative cases per 100k: 21,665 (94,041 total cases)
— 7.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 168 (731 total deaths)
— 26.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.9% (316,248 fully vaccinated)

#15. Solano County, CA

– New cases per 100k in the past week: 112 (503 new cases, +125% change from previous week)
– Cumulative cases per 100k: 19,676 (88,078 total cases)
— 15.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 100 (449 total deaths)
— 55.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.2% (300,903 fully vaccinated)

#14. Los Angeles County, CA

– New cases per 100k in the past week: 120 (12,029 new cases, +15% change from previous week)
– Cumulative cases per 100k: 28,528 (2,863,983 total cases)
— 22.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 316 (31,712 total deaths)
— 39.2% more deaths per 100k residents than California
– Population that is fully vaccinated: 73.2% (7,352,633 fully vaccinated)

#13. Tulare County, CA

– New cases per 100k in the past week: 140 (653 new cases, -16% change from previous week)
– Cumulative cases per 100k: 29,122 (135,763 total cases)
— 24.8% more cases per 100k residents than California
– Cumulative deaths per 100k: 313 (1,458 total deaths)
— 37.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 54.5% (254,102 fully vaccinated)

#12. Humboldt County, CA

– New cases per 100k in the past week: 141 (191 new cases, +53% change from previous week)
– Cumulative cases per 100k: 14,920 (20,225 total cases)
— 36.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 107 (145 total deaths)
— 52.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.3% (89,808 fully vaccinated)

#11. Contra Costa County, CA

– New cases per 100k in the past week: 142 (1,638 new cases, +61% change from previous week)
– Cumulative cases per 100k: 17,839 (205,778 total cases)
— 23.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 113 (1,301 total deaths)
— 50.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 82.3% (949,461 fully vaccinated)

#10. Alameda County, CA

– New cases per 100k in the past week: 157 (2,624 new cases, +47% change from previous week)
– Cumulative cases per 100k: 16,553 (276,662 total cases)
— 29.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 111 (1,851 total deaths)
— 51.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.6% (1,364,573 fully vaccinated)

#9. Sonoma County, CA

– New cases per 100k in the past week: 164 (813 new cases, +48% change from previous week)
– Cumulative cases per 100k: 17,821 (88,095 total cases)
— 23.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 99 (488 total deaths)
— 56.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 78.6% (388,314 fully vaccinated)

#8. Santa Clara County, CA

– New cases per 100k in the past week: 175 (3,381 new cases, +45% change from previous week)
– Cumulative cases per 100k: 17,302 (333,565 total cases)
— 25.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 118 (2,281 total deaths)
— 48.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 85.5% (1,649,116 fully vaccinated)

#7. Glenn County, CA

– New cases per 100k in the past week: 176 (50 new cases, +900% change from previous week)
– Cumulative cases per 100k: 23,319 (6,621 total cases)
— 0.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 169 (48 total deaths)
— 25.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 55.3% (15,698 fully vaccinated)

#6. Napa County, CA

– New cases per 100k in the past week: 181 (250 new cases, +31% change from previous week)
– Cumulative cases per 100k: 19,853 (27,347 total cases)
— 14.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 104 (143 total deaths)
— 54.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 79.0% (108,824 fully vaccinated)

#5. Sacramento County, CA

– New cases per 100k in the past week: 182 (2,828 new cases, +19% change from previous week)
– Cumulative cases per 100k: 20,018 (310,697 total cases)
— 14.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 194 (3,007 total deaths)
— 14.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.6% (1,049,419 fully vaccinated)

#4. Marin County, CA

– New cases per 100k in the past week: 203 (525 new cases, -19% change from previous week)
– Cumulative cases per 100k: 14,416 (37,312 total cases)
— 38.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 112 (291 total deaths)
— 50.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 87.4% (226,121 fully vaccinated)

#3. Santa Cruz County, CA

– New cases per 100k in the past week: 204 (558 new cases, +37% change from previous week)
– Cumulative cases per 100k: 18,667 (51,000 total cases)
— 20.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 96 (262 total deaths)
— 57.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 75.3% (205,790 fully vaccinated)

#2. San Francisco County, CA

– New cases per 100k in the past week: 233 (2,057 new cases, +46% change from previous week)
– Cumulative cases per 100k: 15,757 (138,909 total cases)
— 32.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 98 (860 total deaths)
— 56.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 83.6% (736,825 fully vaccinated)

#1. San Mateo County, CA

– New cases per 100k in the past week: 242 (1,852 new cases, +18% change from previous week)
– Cumulative cases per 100k: 17,374 (133,181 total cases)
— 25.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 92 (705 total deaths)
— 59.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 84.4% (647,347 fully vaccinated)