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 11 reached 998,305 COVID-19-related deaths and 82.1 million COVID-19 cases, according to Johns Hopkins University. Currently, 66.3% of the population is fully vaccinated, and 46.1% 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 10, 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. Lassen County, CA
– New cases per 100k in the past week: 36 (11 new cases, +450% change from previous week)
– Cumulative cases per 100k: 32,277 (9,868 total cases)
— 37.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 213 (65 total deaths)
— 6.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 29.0% (8,880 fully vaccinated)
#49. Lake County, CA
– New cases per 100k in the past week: 37 (24 new cases, +4% change from previous week)
– Cumulative cases per 100k: 18,130 (11,673 total cases)
— 22.8% 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: 55.0% (35,436 fully vaccinated)
#48. Shasta County, CA
– New cases per 100k in the past week: 40 (72 new cases, +44% change from previous week)
– Cumulative cases per 100k: 20,490 (36,898 total cases)
— 12.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 313 (563 total deaths)
— 37.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 46.5% (83,742 fully vaccinated)
#47. Kings County, CA
– New cases per 100k in the past week: 42 (64 new cases, +12% change from previous week)
– Cumulative cases per 100k: 36,185 (55,341 total cases)
— 54.2% 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: 45.2% (69,165 fully vaccinated)
#46. Kern County, CA
– New cases per 100k in the past week: 44 (393 new cases, +12% change from previous week)
– Cumulative cases per 100k: 26,565 (239,142 total cases)
— 13.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 254 (2,287 total deaths)
— 11.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.7% (483,610 fully vaccinated)
#45. Sutter County, CA
– New cases per 100k in the past week: 46 (45 new cases, +12% change from previous week)
– Cumulative cases per 100k: 23,570 (22,856 total cases)
— 0.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 232 (225 total deaths)
— 2.2% more deaths per 100k residents than California
– Population that is fully vaccinated: 60.6% (58,736 fully vaccinated)
#44. Mariposa County, CA
– New cases per 100k in the past week: 47 (8 new cases, -11% change from previous week)
– Cumulative cases per 100k: 15,364 (2,643 total cases)
— 34.5% 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: 45.1% (7,754 fully vaccinated)
#43. Butte County, CA
– New cases per 100k in the past week: 47 (102 new cases, +3% change from previous week)
– Cumulative cases per 100k: 18,254 (40,010 total cases)
— 22.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 192 (421 total deaths)
— 15.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 53.3% (116,933 fully vaccinated)
#42. Merced County, CA
– New cases per 100k in the past week: 54 (149 new cases, +16% change from previous week)
– Cumulative cases per 100k: 25,675 (71,294 total cases)
— 9.4% 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: 51.9% (144,193 fully vaccinated)
#41. Inyo County, CA
– New cases per 100k in the past week: 55 (10 new cases, +43% change from previous week)
– Cumulative cases per 100k: 25,506 (4,601 total cases)
— 8.7% 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: 62.7% (11,305 fully vaccinated)
#40. Calaveras County, CA
– New cases per 100k in the past week: 59 (27 new cases, -25% change from previous week)
– Cumulative cases per 100k: 16,813 (7,718 total cases)
— 28.4% 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: 53.6% (24,616 fully vaccinated)
#39. Mono County, CA
– New cases per 100k in the past week: 62 (9 new cases, +200% change from previous week)
– Cumulative cases per 100k: 21,635 (3,125 total cases)
— 7.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 42 (6 total deaths)
— 81.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 62.6% (9,040 fully vaccinated)
#38. Amador County, CA
– New cases per 100k in the past week: 63 (25 new cases, -22% change from previous week)
– Cumulative cases per 100k: 23,199 (9,222 total cases)
— 1.2% 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: 52.7% (20,938 fully vaccinated)
#37. Stanislaus County, CA
– New cases per 100k in the past week: 64 (352 new cases, +27% change from previous week)
– Cumulative cases per 100k: 24,661 (135,799 total cases)
— 5.1% 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: 57.1% (314,419 fully vaccinated)
#36. Sierra County, CA
– New cases per 100k in the past week: 67 (2 new cases, 0% change from previous week)
– Cumulative cases per 100k: 10,782 (324 total cases)
— 54.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 133 (4 total deaths)
— 41.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 52.5% (1,579 fully vaccinated)
#35. Yuba County, CA
– New cases per 100k in the past week: 72 (57 new cases, +78% change from previous week)
– Cumulative cases per 100k: 21,868 (17,203 total cases)
— 6.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 155 (122 total deaths)
— 31.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 49.3% (38,784 fully vaccinated)
#34. Fresno County, CA
– New cases per 100k in the past week: 72 (723 new cases, +28% change from previous week)
– Cumulative cases per 100k: 25,691 (256,677 total cases)
— 9.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 276 (2,754 total deaths)
— 21.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 61.3% (612,293 fully vaccinated)
#33. El Dorado County, CA
– New cases per 100k in the past week: 78 (151 new cases, +22% change from previous week)
– Cumulative cases per 100k: 15,731 (30,337 total cases)
— 33.0% 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: 61.0% (117,598 fully vaccinated)
#32. San Bernardino County, CA
– New cases per 100k in the past week: 78 (1,704 new cases, -18% change from previous week)
– Cumulative cases per 100k: 27,318 (595,566 total cases)
— 16.4% more cases per 100k residents than California
– Cumulative deaths per 100k: 335 (7,306 total deaths)
— 47.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 57.0% (1,243,365 fully vaccinated)
#31. Nevada County, CA
– New cases per 100k in the past week: 83 (83 new cases, +38% change from previous week)
– Cumulative cases per 100k: 17,459 (17,416 total cases)
— 25.6% 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: 63.3% (63,168 fully vaccinated)
#30. Placer County, CA
– New cases per 100k in the past week: 83 (329 new cases, +27% change from previous week)
– Cumulative cases per 100k: 17,844 (71,079 total cases)
— 24.0% 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: 67.1% (267,380 fully vaccinated)
#29. Imperial County, CA
– New cases per 100k in the past week: 87 (158 new cases, 0% change from previous week)
– Cumulative cases per 100k: 36,765 (66,624 total cases)
— 56.6% more cases per 100k residents than California
– Cumulative deaths per 100k: 506 (917 total deaths)
— 122.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 95.0% (172,356 fully vaccinated)
#28. Riverside County, CA
– New cases per 100k in the past week: 88 (2,183 new cases, +54% change from previous week)
– Cumulative cases per 100k: 25,282 (624,595 total cases)
— 7.7% more cases per 100k residents than California
– Cumulative deaths per 100k: 262 (6,467 total deaths)
— 15.4% more deaths per 100k residents than California
– Population that is fully vaccinated: 58.9% (1,454,835 fully vaccinated)
#27. Alpine County, CA
– New cases per 100k in the past week: 89 (1 new cases, 0% change from previous week)
– Cumulative cases per 100k: 11,160 (126 total cases)
— 52.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 0 (0 total deaths)
— 100.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 63.7% (719 fully vaccinated)
#26. Orange County, CA
– New cases per 100k in the past week: 93 (2,968 new cases, +26% change from previous week)
– Cumulative cases per 100k: 18,802 (597,100 total cases)
— 19.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 221 (7,007 total deaths)
— 2.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.8% (2,310,948 fully vaccinated)
#25. San Benito County, CA
– New cases per 100k in the past week: 102 (64 new cases, +191% change from previous week)
– Cumulative cases per 100k: 21,612 (13,574 total cases)
— 7.9% 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: 72.5% (45,514 fully vaccinated)
#24. Ventura County, CA
– New cases per 100k in the past week: 102 (863 new cases, +36% change from previous week)
– Cumulative cases per 100k: 21,859 (184,928 total cases)
— 6.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 176 (1,491 total deaths)
— 22.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.3% (611,299 fully vaccinated)
#23. Sacramento County, CA
– New cases per 100k in the past week: 104 (1,612 new cases, -43% change from previous week)
– Cumulative cases per 100k: 20,122 (312,309 total cases)
— 14.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 194 (3,016 total deaths)
— 14.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.7% (1,051,318 fully vaccinated)
#22. San Joaquin County, CA
– New cases per 100k in the past week: 106 (810 new cases, +37% change from previous week)
– Cumulative cases per 100k: 23,294 (177,538 total cases)
— 0.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 292 (2,229 total deaths)
— 28.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 61.7% (469,930 fully vaccinated)
#21. Mendocino County, CA
– New cases per 100k in the past week: 108 (94 new cases, 0% change from previous week)
– Cumulative cases per 100k: 18,924 (16,416 total cases)
— 19.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 143 (124 total deaths)
— 37.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 68.9% (59,749 fully vaccinated)
#20. Santa Barbara County, CA
– New cases per 100k in the past week: 112 (499 new cases, +19% change from previous week)
– Cumulative cases per 100k: 20,645 (92,178 total cases)
— 12.0% less cases per 100k residents than California
– Cumulative deaths per 100k: 155 (692 total deaths)
— 31.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.3% (309,600 fully vaccinated)
#19. San Luis Obispo County, CA
– New cases per 100k in the past week: 114 (323 new cases, +24% change from previous week)
– Cumulative cases per 100k: 20,220 (57,246 total cases)
— 13.9% 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: 64.3% (182,015 fully vaccinated)
#18. Monterey County, CA
– New cases per 100k in the past week: 124 (538 new cases, +15% change from previous week)
– Cumulative cases per 100k: 21,789 (94,579 total cases)
— 7.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 169 (733 total deaths)
— 25.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 73.0% (316,908 fully vaccinated)
#17. San Diego County, CA
– New cases per 100k in the past week: 139 (4,644 new cases, +35% change from previous week)
– Cumulative cases per 100k: 24,531 (818,936 total cases)
— 4.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 157 (5,244 total deaths)
— 30.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 74.3% (2,479,539 fully vaccinated)
#16. Yolo County, CA
– New cases per 100k in the past week: 141 (311 new cases, +55% change from previous week)
– Cumulative cases per 100k: 18,474 (40,736 total cases)
— 21.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 143 (315 total deaths)
— 37.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 70.7% (155,921 fully vaccinated)
#15. Solano County, CA
– New cases per 100k in the past week: 141 (633 new cases, +26% change from previous week)
– Cumulative cases per 100k: 19,817 (88,711 total cases)
— 15.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 101 (450 total deaths)
— 55.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.4% (301,645 fully vaccinated)
#14. Tuolumne County, CA
– New cases per 100k in the past week: 152 (83 new cases, +48% change from previous week)
– Cumulative cases per 100k: 24,544 (13,371 total cases)
— 4.6% 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: 52.6% (28,635 fully vaccinated)
#13. Los Angeles County, CA
– New cases per 100k in the past week: 157 (15,752 new cases, +31% change from previous week)
– Cumulative cases per 100k: 28,685 (2,879,735 total cases)
— 22.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 316 (31,738 total deaths)
— 39.2% more deaths per 100k residents than California
– Population that is fully vaccinated: 73.4% (7,367,140 fully vaccinated)
#12. Napa County, CA
– New cases per 100k in the past week: 163 (224 new cases, -10% change from previous week)
– Cumulative cases per 100k: 20,016 (27,571 total cases)
— 14.7% 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: 79.2% (109,030 fully vaccinated)
#11. Del Norte County, CA
– New cases per 100k in the past week: 169 (47 new cases, +194% change from previous week)
– Cumulative cases per 100k: 21,890 (6,088 total cases)
— 6.7% 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: 48.0% (13,342 fully vaccinated)
#10. Contra Costa County, CA
– New cases per 100k in the past week: 172 (1,979 new cases, +21% change from previous week)
– Cumulative cases per 100k: 18,011 (207,757 total cases)
— 23.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 113 (1,302 total deaths)
— 50.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 82.4% (950,886 fully vaccinated)
#9. Alameda County, CA
– New cases per 100k in the past week: 184 (3,072 new cases, +17% change from previous week)
– Cumulative cases per 100k: 16,737 (279,734 total cases)
— 28.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 111 (1,855 total deaths)
— 51.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.8% (1,367,114 fully vaccinated)
#8. Humboldt County, CA
– New cases per 100k in the past week: 190 (258 new cases, +35% change from previous week)
– Cumulative cases per 100k: 15,110 (20,483 total cases)
— 35.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 108 (146 total deaths)
— 52.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.4% (89,998 fully vaccinated)
#7. Sonoma County, CA
– New cases per 100k in the past week: 200 (987 new cases, +21% change from previous week)
– Cumulative cases per 100k: 18,021 (89,082 total cases)
— 23.2% 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: 78.7% (388,955 fully vaccinated)
#6. Marin County, CA
– New cases per 100k in the past week: 216 (560 new cases, +7% change from previous week)
– Cumulative cases per 100k: 14,632 (37,872 total cases)
— 37.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 113 (292 total deaths)
— 50.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 87.6% (226,609 fully vaccinated)
#5. Santa Clara County, CA
– New cases per 100k in the past week: 232 (4,470 new cases, +32% change from previous week)
– Cumulative cases per 100k: 17,534 (338,035 total cases)
— 25.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 119 (2,287 total deaths)
— 47.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 85.7% (1,651,957 fully vaccinated)
#4. San Mateo County, CA
– New cases per 100k in the past week: 260 (1,992 new cases, +8% change from previous week)
– Cumulative cases per 100k: 17,633 (135,173 total cases)
— 24.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 92 (709 total deaths)
— 59.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 84.6% (648,688 fully vaccinated)
#3. Plumas County, CA
– New cases per 100k in the past week: 261 (49 new cases, +308% change from previous week)
– Cumulative cases per 100k: 17,866 (3,360 total cases)
— 23.9% 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% (10,344 fully vaccinated)
#2. San Francisco County, CA
– New cases per 100k in the past week: 293 (2,583 new cases, +26% change from previous week)
– Cumulative cases per 100k: 16,050 (141,492 total cases)
— 31.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 98 (861 total deaths)
— 56.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 83.7% (738,276 fully vaccinated)
#1. Santa Cruz County, CA
– New cases per 100k in the past week: 305 (834 new cases, +49% change from previous week)
– Cumulative cases per 100k: 18,972 (51,834 total cases)
— 19.2% 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: 75.5% (206,315 fully vaccinated)
