This is a daily updated tracker website providing time-varying estimated reproduction numbers for COVID-19 in California, based on both daily case counts and wastewater readings.

We estimate transmission rates of COVID–19 using reproduction numbers. A time-varying reproduction number, commonly written R, is the average number of cases infected by a given case over the course of that individual’s disease progression. Of particular interest is the question of whether transmission is supercritical, meaning that R > 1, in which case the epidemic can increase in size, or is subcritical, meaning that R < 1, in which case it will fade out. To eliminate a disease locally, it is not necessary to reduce R to zero, only to reduce it below one for a sustained period.

We use raw data from three sources: new cases by county from California Health and Human Services, (“Cases”, below); wastewater readings from the Cal-SuWers network (“Wastewater (C)”), WastewaterScan (“Wastewater (W)”), and BioBot Analytics (“Wastewater (B)”).

For more details see the Methods section below.

Recent

R estimates

This is a plot of estimated reproduction numbers in the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Alameda County, from NA, 1.00 on April 16, 2024; in Contra Costa County, from NA, 0.99 on April 16, 2024; in Marin County, from NA, 1.00 on April 16, 2024; in Napa County, from NA, 1.02 on April 15, 2024; in San Francisco County, from NA, 0.99 on April 17, 2024; in San Mateo County, from NA, 0.99 on April 17, 2024; in Santa Clara County, from NA, 0.99 on April 17, 2024; in Solano County, from NA, 0.99 on April 16, 2024; in Sonoma County, from NA, 0.97 on April 17, 2024.

This is a plot of estimated reproduction numbers in the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Alameda County, from NA, 1.00 on April 16, 2024; in Contra Costa County, from NA, 0.99 on April 16, 2024; in Marin County, from NA, 1.00 on April 16, 2024; in Napa County, from NA, 1.02 on April 15, 2024; in San Francisco County, from NA, 0.99 on April 17, 2024; in San Mateo County, from NA, 0.99 on April 17, 2024; in Santa Clara County, from NA, 0.99 on April 17, 2024; in Solano County, from NA, 0.99 on April 16, 2024; in Sonoma County, from NA, 0.97 on April 17, 2024.

This is a plot of estimated reproduction numbers in California outside the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Amador County, from NA, 1.01 on December 18, 2023; in Butte County, from NA, 1.01 on December 18, 2023; in Calaveras County, from NA, 1.00 on December 18, 2023; in Colusa County, from NA, 1.00 on December 17, 2023; in Del Norte County, from NA, 0.98 on December 18, 2023; in El Dorado County, from NA, 0.99 on December 18, 2023; in Fresno County, from NA, 0.99 on December 18, 2023; in Glenn County, from NA, 0.98 on December 18, 2023; in Humboldt County, from NA, 0.99 on December 18, 2023; in Imperial County, from NA, 0.99 on December 18, 2023; in Inyo County, from NA, 0.99 on July 08, 2023; in Kern County, from NA, 0.99 on December 18, 2023; in Kings County, from NA, 1.00 on December 18, 2023; in Lake County, from NA, 1.00 on December 17, 2023; in Lassen County, from NA, 0.96 on June 13, 2023; in Los Angeles County, from NA, 1.02 on April 16, 2024; in Madera County, from NA, 0.96 on April 17, 2024; in Mariposa County, from NA, 1.02 on April 24, 2023; in Mendocino County, from NA, 1.02 on December 18, 2023; in Merced County, from NA, 0.98 on April 16, 2024; in Mono County, from NA, 1.00 on April 12, 2024; in Monterey County, from NA, 1.02 on April 15, 2024; in Nevada County, from NA, 1.01 on December 18, 2023; in Orange County, from NA, 0.97 on April 17, 2024; in Placer County, from NA, 1.00 on December 18, 2023; in Plumas County, from NA, 0.98 on June 13, 2023; in Riverside County, from NA, 0.99 on April 15, 2024; in Sacramento County, from NA, 0.96 on April 17, 2024; in San Benito County, from NA, 1.02 on April 15, 2024; in San Bernardino County, from NA, 0.98 on April 17, 2024; in San Diego County, from NA, 1.03 on April 15, 2024; in San Joaquin County, from NA, 0.99 on December 18, 2023; in San Luis Obispo County, from NA, 1.03 on April 16, 2024; in Santa Barbara County, from NA, 1.00 on April 15, 2024; in Santa Cruz County, from NA, 0.97 on April 14, 2024; in Shasta County, from NA, 1.00 on December 18, 2023; in Siskiyou County, from NA, 1.00 on December 18, 2023; in Stanislaus County, from NA, 0.92 on April 17, 2024; in Sutter County, from NA, 1.01 on December 18, 2023; in Tehama County, from NA, 1.01 on December 18, 2023; in Trinity County, from NA, 0.97 on March 13, 2022; in Tulare County, from NA, 1.00 on December 18, 2023; in Tuolumne County, from NA, 0.99 on December 18, 2023; in Ventura County, from NA, 1.01 on December 18, 2023; in Yolo County, from NA, 0.99 on April 17, 2024; in Yuba County, from NA, 0.99 on December 18, 2023.

This is a plot of estimated reproduction numbers in California outside the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Amador County, from NA, 1.01 on December 18, 2023; in Butte County, from NA, 1.01 on December 18, 2023; in Calaveras County, from NA, 1.00 on December 18, 2023; in Colusa County, from NA, 1.00 on December 17, 2023; in Del Norte County, from NA, 0.98 on December 18, 2023; in El Dorado County, from NA, 0.99 on December 18, 2023; in Fresno County, from NA, 0.99 on December 18, 2023; in Glenn County, from NA, 0.98 on December 18, 2023; in Humboldt County, from NA, 0.99 on December 18, 2023; in Imperial County, from NA, 0.99 on December 18, 2023; in Inyo County, from NA, 0.99 on July 08, 2023; in Kern County, from NA, 0.99 on December 18, 2023; in Kings County, from NA, 1.00 on December 18, 2023; in Lake County, from NA, 1.00 on December 17, 2023; in Lassen County, from NA, 0.96 on June 13, 2023; in Los Angeles County, from NA, 1.02 on April 16, 2024; in Madera County, from NA, 0.96 on April 17, 2024; in Mariposa County, from NA, 1.02 on April 24, 2023; in Mendocino County, from NA, 1.02 on December 18, 2023; in Merced County, from NA, 0.98 on April 16, 2024; in Mono County, from NA, 1.00 on April 12, 2024; in Monterey County, from NA, 1.02 on April 15, 2024; in Nevada County, from NA, 1.01 on December 18, 2023; in Orange County, from NA, 0.97 on April 17, 2024; in Placer County, from NA, 1.00 on December 18, 2023; in Plumas County, from NA, 0.98 on June 13, 2023; in Riverside County, from NA, 0.99 on April 15, 2024; in Sacramento County, from NA, 0.96 on April 17, 2024; in San Benito County, from NA, 1.02 on April 15, 2024; in San Bernardino County, from NA, 0.98 on April 17, 2024; in San Diego County, from NA, 1.03 on April 15, 2024; in San Joaquin County, from NA, 0.99 on December 18, 2023; in San Luis Obispo County, from NA, 1.03 on April 16, 2024; in Santa Barbara County, from NA, 1.00 on April 15, 2024; in Santa Cruz County, from NA, 0.97 on April 14, 2024; in Shasta County, from NA, 1.00 on December 18, 2023; in Siskiyou County, from NA, 1.00 on December 18, 2023; in Stanislaus County, from NA, 0.92 on April 17, 2024; in Sutter County, from NA, 1.01 on December 18, 2023; in Tehama County, from NA, 1.01 on December 18, 2023; in Trinity County, from NA, 0.97 on March 13, 2022; in Tulare County, from NA, 1.00 on December 18, 2023; in Tuolumne County, from NA, 0.99 on December 18, 2023; in Ventura County, from NA, 1.01 on December 18, 2023; in Yolo County, from NA, 0.99 on April 17, 2024; in Yuba County, from NA, 0.99 on December 18, 2023.

Wastewater

This is a plot of individual and smoothed wastewater readings in the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alameda County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.2 as of April 09, 2024, from NA, 11.3 as of April 16, 2024; in Contra Costa County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.4 as of April 09, 2024, from NA, 11.1 as of April 16, 2024; in Marin County, from the state, 3.4 as of April 10, 2024, from NA, 25.6 as of April 16, 2024; in Napa County, from the state, 0.5 as of April 08, 2024, from NA, 6.3 as of April 15, 2024; in San Francisco County, from the state, 3.4 as of April 10, 2024, from NA, 19.3 as of April 17, 2024; in San Mateo County, from the state, 2.4 as of April 10, 2024, from NA, 14.7 as of April 17, 2024; in Santa Clara County, from the state, 1.1 as of April 10, 2024, from NA, 8.1 as of April 17, 2024; in Solano County, from the state, 0.8 as of April 10, 2024, from NA, 5.7 as of April 16, 2024; in Sonoma County, from BioBot, 2.3 as of May 03, 2023, from the state, 1.5 as of April 10, 2024, from NA, 9 as of April 17, 2024.

This is a plot of individual and smoothed wastewater readings in the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alameda County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.2 as of April 09, 2024, from NA, 11.3 as of April 16, 2024; in Contra Costa County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.4 as of April 09, 2024, from NA, 11.1 as of April 16, 2024; in Marin County, from the state, 3.4 as of April 10, 2024, from NA, 25.6 as of April 16, 2024; in Napa County, from the state, 0.5 as of April 08, 2024, from NA, 6.3 as of April 15, 2024; in San Francisco County, from the state, 3.4 as of April 10, 2024, from NA, 19.3 as of April 17, 2024; in San Mateo County, from the state, 2.4 as of April 10, 2024, from NA, 14.7 as of April 17, 2024; in Santa Clara County, from the state, 1.1 as of April 10, 2024, from NA, 8.1 as of April 17, 2024; in Solano County, from the state, 0.8 as of April 10, 2024, from NA, 5.7 as of April 16, 2024; in Sonoma County, from BioBot, 2.3 as of May 03, 2023, from the state, 1.5 as of April 10, 2024, from NA, 9 as of April 17, 2024.

This is a plot of individual and smoothed wastewater readings in California outside the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in El Dorado County, from BioBot, 4.9 as of May 03, 2023; in Fresno County, from the state, 2.2 as of May 01, 2023; in Imperial County, from the state, 1 as of May 08, 2023; in Kern County, from the state, 1.2 as of May 04, 2023; in Kings County, from BioBot, 0.9 as of May 03, 2023; in Lake County, from BioBot, 0.6 as of May 03, 2023, from the state, 0.7 as of April 24, 2023; in Los Angeles County, from BioBot, 2.2 as of May 03, 2023, from the state, 0.4 as of April 09, 2024, from NA, 3.4 as of April 16, 2024; in Madera County, from the state, 0.2 as of April 10, 2024, from NA, 1.3 as of April 17, 2024; in Merced County, from the state, 0.3 as of April 09, 2024, from NA, 2.3 as of April 16, 2024; in Mono County, from the state, 0.6 as of April 10, 2024, from NA, 5 as of April 12, 2024; in Monterey County, from BioBot, 1.4 as of May 03, 2023, from the state, 0.7 as of April 08, 2024, from NA, 7.3 as of April 15, 2024; in Orange County, from the state, 1.7 as of April 10, 2024, from NA, 8.9 as of April 17, 2024; in Placer County, from BioBot, 7 as of December 07, 2022; in Plumas County, from the state, 2.5 as of May 02, 2023; in Riverside County, from BioBot, 1.9 as of May 03, 2023, from the state, 0.2 as of April 08, 2024, from NA, 1.4 as of April 15, 2024; in Sacramento County, from BioBot, 2.1 as of May 03, 2023, from the state, 1.8 as of April 10, 2024, from NA, 9.9 as of April 17, 2024; in San Benito County, from the state, 2.9 as of April 10, 2024, from NA, 6.6 as of April 15, 2024; in San Bernardino County, from the state, 0.3 as of April 08, 2024, from NA, 1.4 as of April 17, 2024; in San Diego County, from BioBot, 2.1 as of May 03, 2023, from the state, 0.3 as of April 08, 2024, from NA, 4.7 as of April 15, 2024; in San Joaquin County, from BioBot, 2 as of May 03, 2023; in San Luis Obispo County, from BioBot, 4.1 as of May 03, 2023, from the state, 0.3 as of April 09, 2024, from NA, 3.1 as of April 16, 2024; in Santa Barbara County, from the state, 0.4 as of April 08, 2024, from NA, 3.7 as of April 15, 2024; in Santa Cruz County, from BioBot, 1.7 as of May 03, 2023, from the state, 2 as of April 07, 2024, from NA, 12.8 as of April 14, 2024; in Stanislaus County, from the state, 0.6 as of April 10, 2024, from NA, 2.3 as of April 17, 2024; in Ventura County, from the state, 1.3 as of May 02, 2023; in Yolo County, from the state, 0.4 as of April 10, 2024, from NA, 3 as of April 17, 2024.

This is a plot of individual and smoothed wastewater readings in California outside the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in El Dorado County, from BioBot, 4.9 as of May 03, 2023; in Fresno County, from the state, 2.2 as of May 01, 2023; in Imperial County, from the state, 1 as of May 08, 2023; in Kern County, from the state, 1.2 as of May 04, 2023; in Kings County, from BioBot, 0.9 as of May 03, 2023; in Lake County, from BioBot, 0.6 as of May 03, 2023, from the state, 0.7 as of April 24, 2023; in Los Angeles County, from BioBot, 2.2 as of May 03, 2023, from the state, 0.4 as of April 09, 2024, from NA, 3.4 as of April 16, 2024; in Madera County, from the state, 0.2 as of April 10, 2024, from NA, 1.3 as of April 17, 2024; in Merced County, from the state, 0.3 as of April 09, 2024, from NA, 2.3 as of April 16, 2024; in Mono County, from the state, 0.6 as of April 10, 2024, from NA, 5 as of April 12, 2024; in Monterey County, from BioBot, 1.4 as of May 03, 2023, from the state, 0.7 as of April 08, 2024, from NA, 7.3 as of April 15, 2024; in Orange County, from the state, 1.7 as of April 10, 2024, from NA, 8.9 as of April 17, 2024; in Placer County, from BioBot, 7 as of December 07, 2022; in Plumas County, from the state, 2.5 as of May 02, 2023; in Riverside County, from BioBot, 1.9 as of May 03, 2023, from the state, 0.2 as of April 08, 2024, from NA, 1.4 as of April 15, 2024; in Sacramento County, from BioBot, 2.1 as of May 03, 2023, from the state, 1.8 as of April 10, 2024, from NA, 9.9 as of April 17, 2024; in San Benito County, from the state, 2.9 as of April 10, 2024, from NA, 6.6 as of April 15, 2024; in San Bernardino County, from the state, 0.3 as of April 08, 2024, from NA, 1.4 as of April 17, 2024; in San Diego County, from BioBot, 2.1 as of May 03, 2023, from the state, 0.3 as of April 08, 2024, from NA, 4.7 as of April 15, 2024; in San Joaquin County, from BioBot, 2 as of May 03, 2023; in San Luis Obispo County, from BioBot, 4.1 as of May 03, 2023, from the state, 0.3 as of April 09, 2024, from NA, 3.1 as of April 16, 2024; in Santa Barbara County, from the state, 0.4 as of April 08, 2024, from NA, 3.7 as of April 15, 2024; in Santa Cruz County, from BioBot, 1.7 as of May 03, 2023, from the state, 2 as of April 07, 2024, from NA, 12.8 as of April 14, 2024; in Stanislaus County, from the state, 0.6 as of April 10, 2024, from NA, 2.3 as of April 17, 2024; in Ventura County, from the state, 1.3 as of May 02, 2023; in Yolo County, from the state, 0.4 as of April 10, 2024, from NA, 3 as of April 17, 2024.

Historical

R estimates

This is a plot of estimated reproduction numbers in the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Alameda County, from NA, 1.00 on April 16, 2024; in Contra Costa County, from NA, 0.99 on April 16, 2024; in Marin County, from NA, 1.00 on April 16, 2024; in Napa County, from NA, 1.02 on April 15, 2024; in San Francisco County, from NA, 0.99 on April 17, 2024; in San Mateo County, from NA, 0.99 on April 17, 2024; in Santa Clara County, from NA, 0.99 on April 17, 2024; in Solano County, from NA, 0.99 on April 16, 2024; in Sonoma County, from NA, 0.97 on April 17, 2024.

This is a plot of estimated reproduction numbers in the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Alameda County, from NA, 1.00 on April 16, 2024; in Contra Costa County, from NA, 0.99 on April 16, 2024; in Marin County, from NA, 1.00 on April 16, 2024; in Napa County, from NA, 1.02 on April 15, 2024; in San Francisco County, from NA, 0.99 on April 17, 2024; in San Mateo County, from NA, 0.99 on April 17, 2024; in Santa Clara County, from NA, 0.99 on April 17, 2024; in Solano County, from NA, 0.99 on April 16, 2024; in Sonoma County, from NA, 0.97 on April 17, 2024.

This is a plot of estimated reproduction numbers in California outside the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Amador County, from NA, 1.01 on December 18, 2023; in Butte County, from NA, 1.01 on December 18, 2023; in Calaveras County, from NA, 1.00 on December 18, 2023; in Colusa County, from NA, 1.00 on December 17, 2023; in Del Norte County, from NA, 0.98 on December 18, 2023; in El Dorado County, from NA, 0.99 on December 18, 2023; in Fresno County, from NA, 0.99 on December 18, 2023; in Glenn County, from NA, 0.98 on December 18, 2023; in Humboldt County, from NA, 0.99 on December 18, 2023; in Imperial County, from NA, 0.99 on December 18, 2023; in Inyo County, from NA, 0.99 on July 08, 2023; in Kern County, from NA, 0.99 on December 18, 2023; in Kings County, from NA, 1.00 on December 18, 2023; in Lake County, from NA, 1.00 on December 17, 2023; in Lassen County, from NA, 0.96 on June 13, 2023; in Los Angeles County, from NA, 1.02 on April 16, 2024; in Madera County, from NA, 0.96 on April 17, 2024; in Mariposa County, from NA, 1.02 on April 24, 2023; in Mendocino County, from NA, 1.02 on December 18, 2023; in Merced County, from NA, 0.98 on April 16, 2024; in Mono County, from NA, 1.00 on April 12, 2024; in Monterey County, from NA, 1.02 on April 15, 2024; in Nevada County, from NA, 1.01 on December 18, 2023; in Orange County, from NA, 0.97 on April 17, 2024; in Placer County, from NA, 1.00 on December 18, 2023; in Plumas County, from NA, 0.98 on June 13, 2023; in Riverside County, from NA, 0.99 on April 15, 2024; in Sacramento County, from NA, 0.96 on April 17, 2024; in San Benito County, from NA, 1.02 on April 15, 2024; in San Bernardino County, from NA, 0.98 on April 17, 2024; in San Diego County, from NA, 1.03 on April 15, 2024; in San Joaquin County, from NA, 0.99 on December 18, 2023; in San Luis Obispo County, from NA, 1.03 on April 16, 2024; in Santa Barbara County, from NA, 1.00 on April 15, 2024; in Santa Cruz County, from NA, 0.97 on April 14, 2024; in Shasta County, from NA, 1.00 on December 18, 2023; in Siskiyou County, from NA, 1.00 on December 18, 2023; in Stanislaus County, from NA, 0.92 on April 17, 2024; in Sutter County, from NA, 1.01 on December 18, 2023; in Tehama County, from NA, 1.01 on December 18, 2023; in Trinity County, from NA, 0.97 on March 13, 2022; in Tulare County, from NA, 1.00 on December 18, 2023; in Tuolumne County, from NA, 0.99 on December 18, 2023; in Ventura County, from NA, 1.01 on December 18, 2023; in Yolo County, from NA, 0.99 on April 17, 2024; in Yuba County, from NA, 0.99 on December 18, 2023.

This is a plot of estimated reproduction numbers in California outside the Bay Area. For the complete timeseries, see the csv data linked below. The latest estimates are as follows: in Amador County, from NA, 1.01 on December 18, 2023; in Butte County, from NA, 1.01 on December 18, 2023; in Calaveras County, from NA, 1.00 on December 18, 2023; in Colusa County, from NA, 1.00 on December 17, 2023; in Del Norte County, from NA, 0.98 on December 18, 2023; in El Dorado County, from NA, 0.99 on December 18, 2023; in Fresno County, from NA, 0.99 on December 18, 2023; in Glenn County, from NA, 0.98 on December 18, 2023; in Humboldt County, from NA, 0.99 on December 18, 2023; in Imperial County, from NA, 0.99 on December 18, 2023; in Inyo County, from NA, 0.99 on July 08, 2023; in Kern County, from NA, 0.99 on December 18, 2023; in Kings County, from NA, 1.00 on December 18, 2023; in Lake County, from NA, 1.00 on December 17, 2023; in Lassen County, from NA, 0.96 on June 13, 2023; in Los Angeles County, from NA, 1.02 on April 16, 2024; in Madera County, from NA, 0.96 on April 17, 2024; in Mariposa County, from NA, 1.02 on April 24, 2023; in Mendocino County, from NA, 1.02 on December 18, 2023; in Merced County, from NA, 0.98 on April 16, 2024; in Mono County, from NA, 1.00 on April 12, 2024; in Monterey County, from NA, 1.02 on April 15, 2024; in Nevada County, from NA, 1.01 on December 18, 2023; in Orange County, from NA, 0.97 on April 17, 2024; in Placer County, from NA, 1.00 on December 18, 2023; in Plumas County, from NA, 0.98 on June 13, 2023; in Riverside County, from NA, 0.99 on April 15, 2024; in Sacramento County, from NA, 0.96 on April 17, 2024; in San Benito County, from NA, 1.02 on April 15, 2024; in San Bernardino County, from NA, 0.98 on April 17, 2024; in San Diego County, from NA, 1.03 on April 15, 2024; in San Joaquin County, from NA, 0.99 on December 18, 2023; in San Luis Obispo County, from NA, 1.03 on April 16, 2024; in Santa Barbara County, from NA, 1.00 on April 15, 2024; in Santa Cruz County, from NA, 0.97 on April 14, 2024; in Shasta County, from NA, 1.00 on December 18, 2023; in Siskiyou County, from NA, 1.00 on December 18, 2023; in Stanislaus County, from NA, 0.92 on April 17, 2024; in Sutter County, from NA, 1.01 on December 18, 2023; in Tehama County, from NA, 1.01 on December 18, 2023; in Trinity County, from NA, 0.97 on March 13, 2022; in Tulare County, from NA, 1.00 on December 18, 2023; in Tuolumne County, from NA, 0.99 on December 18, 2023; in Ventura County, from NA, 1.01 on December 18, 2023; in Yolo County, from NA, 0.99 on April 17, 2024; in Yuba County, from NA, 0.99 on December 18, 2023.

Case counts

This is a plot of daily and smoothed counts of new cases per ten thousand population per day in the Bay Area. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alameda County, 0.5 as of December 18, 2023; in Contra Costa County, 0.5 as of December 18, 2023; in Marin County, 0.4 as of December 18, 2023; in Napa County, 0.4 as of December 18, 2023; in San Francisco County, 0.5 as of December 18, 2023; in San Mateo County, 0.5 as of December 18, 2023; in Santa Clara County, 0.5 as of December 18, 2023; in Solano County, 0.5 as of December 18, 2023; in Sonoma County, 0.4 as of December 18, 2023.

This is a plot of daily and smoothed counts of new cases per ten thousand population per day in the Bay Area. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alameda County, 0.5 as of December 18, 2023; in Contra Costa County, 0.5 as of December 18, 2023; in Marin County, 0.4 as of December 18, 2023; in Napa County, 0.4 as of December 18, 2023; in San Francisco County, 0.5 as of December 18, 2023; in San Mateo County, 0.5 as of December 18, 2023; in Santa Clara County, 0.5 as of December 18, 2023; in Solano County, 0.5 as of December 18, 2023; in Sonoma County, 0.4 as of December 18, 2023.

This is a plot of daily and smoothed counts of new cases per ten thousand population per day in California outside the Bay Area. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alpine County, 9 as of October 18, 2023; in Amador County, 0.8 as of December 18, 2023; in Butte County, 0.3 as of December 18, 2023; in Calaveras County, 0.6 as of December 18, 2023; in Colusa County, 0.6 as of December 17, 2023; in Del Norte County, 0.5 as of December 18, 2023; in El Dorado County, 0.3 as of December 18, 2023; in Fresno County, 0.4 as of December 18, 2023; in Glenn County, 0.5 as of December 18, 2023; in Humboldt County, 0.3 as of December 18, 2023; in Imperial County, 0.6 as of December 18, 2023; in Inyo County, 0.5 as of July 08, 2023; in Kern County, 0.2 as of December 18, 2023; in Kings County, 0.5 as of December 18, 2023; in Lake County, 0.4 as of December 17, 2023; in Lassen County, 0.4 as of June 13, 2023; in Los Angeles County, 0.4 as of December 18, 2023; in Madera County, 0.3 as of December 18, 2023; in Mariposa County, 0.8 as of April 24, 2023; in Mendocino County, 0.3 as of December 18, 2023; in Merced County, 0.4 as of December 18, 2023; in Modoc County, 1.1 as of July 02, 2023; in Mono County, 0.7 as of April 27, 2023; in Monterey County, 0.2 as of December 18, 2023; in Nevada County, 0.4 as of December 18, 2023; in Orange County, 0.4 as of December 18, 2023; in Placer County, 0.5 as of December 18, 2023; in Plumas County, 0.5 as of June 13, 2023; in Riverside County, 0.3 as of December 18, 2023; in Sacramento County, 0.5 as of December 18, 2023; in San Benito County, 0.6 as of December 18, 2023; in San Bernardino County, 0.4 as of December 18, 2023; in San Diego County, 0.4 as of December 18, 2023; in San Joaquin County, 0.5 as of December 18, 2023; in San Luis Obispo County, 0.3 as of December 18, 2023; in Santa Barbara County, 0.4 as of December 18, 2023; in Santa Cruz County, 0.3 as of December 18, 2023; in Shasta County, 0.3 as of December 18, 2023; in Sierra County, 3.2 as of November 20, 2023; in Siskiyou County, 0.5 as of December 18, 2023; in Stanislaus County, 0.5 as of December 18, 2023; in Sutter County, 0.5 as of December 18, 2023; in Tehama County, 0.7 as of December 18, 2023; in Trinity County, 0.7 as of December 08, 2023; in Tulare County, 0.2 as of December 18, 2023; in Tuolumne County, 0.9 as of December 18, 2023; in Ventura County, 0.5 as of December 18, 2023; in Yolo County, 0.3 as of December 18, 2023; in Yuba County, 0.5 as of December 18, 2023.

This is a plot of daily and smoothed counts of new cases per ten thousand population per day in California outside the Bay Area. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alpine County, 9 as of October 18, 2023; in Amador County, 0.8 as of December 18, 2023; in Butte County, 0.3 as of December 18, 2023; in Calaveras County, 0.6 as of December 18, 2023; in Colusa County, 0.6 as of December 17, 2023; in Del Norte County, 0.5 as of December 18, 2023; in El Dorado County, 0.3 as of December 18, 2023; in Fresno County, 0.4 as of December 18, 2023; in Glenn County, 0.5 as of December 18, 2023; in Humboldt County, 0.3 as of December 18, 2023; in Imperial County, 0.6 as of December 18, 2023; in Inyo County, 0.5 as of July 08, 2023; in Kern County, 0.2 as of December 18, 2023; in Kings County, 0.5 as of December 18, 2023; in Lake County, 0.4 as of December 17, 2023; in Lassen County, 0.4 as of June 13, 2023; in Los Angeles County, 0.4 as of December 18, 2023; in Madera County, 0.3 as of December 18, 2023; in Mariposa County, 0.8 as of April 24, 2023; in Mendocino County, 0.3 as of December 18, 2023; in Merced County, 0.4 as of December 18, 2023; in Modoc County, 1.1 as of July 02, 2023; in Mono County, 0.7 as of April 27, 2023; in Monterey County, 0.2 as of December 18, 2023; in Nevada County, 0.4 as of December 18, 2023; in Orange County, 0.4 as of December 18, 2023; in Placer County, 0.5 as of December 18, 2023; in Plumas County, 0.5 as of June 13, 2023; in Riverside County, 0.3 as of December 18, 2023; in Sacramento County, 0.5 as of December 18, 2023; in San Benito County, 0.6 as of December 18, 2023; in San Bernardino County, 0.4 as of December 18, 2023; in San Diego County, 0.4 as of December 18, 2023; in San Joaquin County, 0.5 as of December 18, 2023; in San Luis Obispo County, 0.3 as of December 18, 2023; in Santa Barbara County, 0.4 as of December 18, 2023; in Santa Cruz County, 0.3 as of December 18, 2023; in Shasta County, 0.3 as of December 18, 2023; in Sierra County, 3.2 as of November 20, 2023; in Siskiyou County, 0.5 as of December 18, 2023; in Stanislaus County, 0.5 as of December 18, 2023; in Sutter County, 0.5 as of December 18, 2023; in Tehama County, 0.7 as of December 18, 2023; in Trinity County, 0.7 as of December 08, 2023; in Tulare County, 0.2 as of December 18, 2023; in Tuolumne County, 0.9 as of December 18, 2023; in Ventura County, 0.5 as of December 18, 2023; in Yolo County, 0.3 as of December 18, 2023; in Yuba County, 0.5 as of December 18, 2023.

Wastewater

This is a plot of individual and smoothed wastewater readings in the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alameda County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.2 as of April 09, 2024, from NA, 11.3 as of April 16, 2024; in Contra Costa County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.4 as of April 09, 2024, from NA, 11.1 as of April 16, 2024; in Marin County, from the state, 3.4 as of April 10, 2024, from NA, 25.6 as of April 16, 2024; in Napa County, from the state, 0.5 as of April 08, 2024, from NA, 6.3 as of April 15, 2024; in San Francisco County, from the state, 3.4 as of April 10, 2024, from NA, 19.3 as of April 17, 2024; in San Mateo County, from the state, 2.4 as of April 10, 2024, from NA, 14.7 as of April 17, 2024; in Santa Clara County, from the state, 1.1 as of April 10, 2024, from NA, 8.1 as of April 17, 2024; in Solano County, from the state, 0.8 as of April 10, 2024, from NA, 5.7 as of April 16, 2024; in Sonoma County, from BioBot, 2.3 as of May 03, 2023, from the state, 1.5 as of April 10, 2024, from NA, 9 as of April 17, 2024.

This is a plot of individual and smoothed wastewater readings in the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in Alameda County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.2 as of April 09, 2024, from NA, 11.3 as of April 16, 2024; in Contra Costa County, from BioBot, 2.4 as of May 03, 2023, from the state, 1.4 as of April 09, 2024, from NA, 11.1 as of April 16, 2024; in Marin County, from the state, 3.4 as of April 10, 2024, from NA, 25.6 as of April 16, 2024; in Napa County, from the state, 0.5 as of April 08, 2024, from NA, 6.3 as of April 15, 2024; in San Francisco County, from the state, 3.4 as of April 10, 2024, from NA, 19.3 as of April 17, 2024; in San Mateo County, from the state, 2.4 as of April 10, 2024, from NA, 14.7 as of April 17, 2024; in Santa Clara County, from the state, 1.1 as of April 10, 2024, from NA, 8.1 as of April 17, 2024; in Solano County, from the state, 0.8 as of April 10, 2024, from NA, 5.7 as of April 16, 2024; in Sonoma County, from BioBot, 2.3 as of May 03, 2023, from the state, 1.5 as of April 10, 2024, from NA, 9 as of April 17, 2024.

This is a plot of individual and smoothed wastewater readings in California outside the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in El Dorado County, from BioBot, 4.9 as of May 03, 2023; in Fresno County, from the state, 2.2 as of May 01, 2023; in Imperial County, from the state, 1 as of May 08, 2023; in Kern County, from the state, 1.2 as of May 04, 2023; in Kings County, from BioBot, 0.9 as of May 03, 2023; in Lake County, from BioBot, 0.6 as of May 03, 2023, from the state, 0.7 as of April 24, 2023; in Los Angeles County, from BioBot, 2.2 as of May 03, 2023, from the state, 0.4 as of April 09, 2024, from NA, 3.4 as of April 16, 2024; in Madera County, from the state, 0.2 as of April 10, 2024, from NA, 1.3 as of April 17, 2024; in Merced County, from the state, 0.3 as of April 09, 2024, from NA, 2.3 as of April 16, 2024; in Mono County, from the state, 0.6 as of April 10, 2024, from NA, 5 as of April 12, 2024; in Monterey County, from BioBot, 1.4 as of May 03, 2023, from the state, 0.7 as of April 08, 2024, from NA, 7.3 as of April 15, 2024; in Orange County, from the state, 1.7 as of April 10, 2024, from NA, 8.9 as of April 17, 2024; in Placer County, from BioBot, 7 as of December 07, 2022; in Plumas County, from the state, 2.5 as of May 02, 2023; in Riverside County, from BioBot, 1.9 as of May 03, 2023, from the state, 0.2 as of April 08, 2024, from NA, 1.4 as of April 15, 2024; in Sacramento County, from BioBot, 2.1 as of May 03, 2023, from the state, 1.8 as of April 10, 2024, from NA, 9.9 as of April 17, 2024; in San Benito County, from the state, 2.9 as of April 10, 2024, from NA, 6.6 as of April 15, 2024; in San Bernardino County, from the state, 0.3 as of April 08, 2024, from NA, 1.4 as of April 17, 2024; in San Diego County, from BioBot, 2.1 as of May 03, 2023, from the state, 0.3 as of April 08, 2024, from NA, 4.7 as of April 15, 2024; in San Joaquin County, from BioBot, 2 as of May 03, 2023; in San Luis Obispo County, from BioBot, 4.1 as of May 03, 2023, from the state, 0.3 as of April 09, 2024, from NA, 3.1 as of April 16, 2024; in Santa Barbara County, from the state, 0.4 as of April 08, 2024, from NA, 3.7 as of April 15, 2024; in Santa Cruz County, from BioBot, 1.7 as of May 03, 2023, from the state, 2 as of April 07, 2024, from NA, 12.8 as of April 14, 2024; in Stanislaus County, from the state, 0.6 as of April 10, 2024, from NA, 2.3 as of April 17, 2024; in Ventura County, from the state, 1.3 as of May 02, 2023; in Yolo County, from the state, 0.4 as of April 10, 2024, from NA, 3 as of April 17, 2024.

This is a plot of individual and smoothed wastewater readings in California outside the Bay Area. All values are gene copies per ten thousand copies of the pepper moth virus control detected. For the complete timeseries, see the csv data linked below. The latest smoothed readings are as follows: in El Dorado County, from BioBot, 4.9 as of May 03, 2023; in Fresno County, from the state, 2.2 as of May 01, 2023; in Imperial County, from the state, 1 as of May 08, 2023; in Kern County, from the state, 1.2 as of May 04, 2023; in Kings County, from BioBot, 0.9 as of May 03, 2023; in Lake County, from BioBot, 0.6 as of May 03, 2023, from the state, 0.7 as of April 24, 2023; in Los Angeles County, from BioBot, 2.2 as of May 03, 2023, from the state, 0.4 as of April 09, 2024, from NA, 3.4 as of April 16, 2024; in Madera County, from the state, 0.2 as of April 10, 2024, from NA, 1.3 as of April 17, 2024; in Merced County, from the state, 0.3 as of April 09, 2024, from NA, 2.3 as of April 16, 2024; in Mono County, from the state, 0.6 as of April 10, 2024, from NA, 5 as of April 12, 2024; in Monterey County, from BioBot, 1.4 as of May 03, 2023, from the state, 0.7 as of April 08, 2024, from NA, 7.3 as of April 15, 2024; in Orange County, from the state, 1.7 as of April 10, 2024, from NA, 8.9 as of April 17, 2024; in Placer County, from BioBot, 7 as of December 07, 2022; in Plumas County, from the state, 2.5 as of May 02, 2023; in Riverside County, from BioBot, 1.9 as of May 03, 2023, from the state, 0.2 as of April 08, 2024, from NA, 1.4 as of April 15, 2024; in Sacramento County, from BioBot, 2.1 as of May 03, 2023, from the state, 1.8 as of April 10, 2024, from NA, 9.9 as of April 17, 2024; in San Benito County, from the state, 2.9 as of April 10, 2024, from NA, 6.6 as of April 15, 2024; in San Bernardino County, from the state, 0.3 as of April 08, 2024, from NA, 1.4 as of April 17, 2024; in San Diego County, from BioBot, 2.1 as of May 03, 2023, from the state, 0.3 as of April 08, 2024, from NA, 4.7 as of April 15, 2024; in San Joaquin County, from BioBot, 2 as of May 03, 2023; in San Luis Obispo County, from BioBot, 4.1 as of May 03, 2023, from the state, 0.3 as of April 09, 2024, from NA, 3.1 as of April 16, 2024; in Santa Barbara County, from the state, 0.4 as of April 08, 2024, from NA, 3.7 as of April 15, 2024; in Santa Cruz County, from BioBot, 1.7 as of May 03, 2023, from the state, 2 as of April 07, 2024, from NA, 12.8 as of April 14, 2024; in Stanislaus County, from the state, 0.6 as of April 10, 2024, from NA, 2.3 as of April 17, 2024; in Ventura County, from the state, 1.3 as of May 02, 2023; in Yolo County, from the state, 0.4 as of April 10, 2024, from NA, 3 as of April 17, 2024.

Downloads

R estimates and smoothed case counts and wastewater readings.

Methods

Daily new cases by county are downloaded daily from the California Health and Human Services Open Data Portal.

Wastewater readings are downloaded from the data.ca.gov Open Data Portal and from WastewaterScan each day. Counts of the n and s gene targets are used, normalized to counts of the pepper mottle virus. Counts for which the PPMoV control is not present are excluded. Each count is used in all counties included in its wastewater collection region. The wastewater estimates published by BioBot Analytics are included as well, because they include some additional locations. Exceptionally high wastewater counts are indicated by ^ signs at the top of each plot.

We apply kernel density smoothing with a Gaussian kernel with bandwidth of 14 days to both wastewater and case counts, to de-emphasize day-to-day fluctuations and pick out longer-term changes.

The Wallinga-Teunis technique is used to estimate reproduction numbers, corrected for right censoring of the case detection data, and a small number of the earliest days are trimmed from the estimates to avoid artifacts due to left censoring. Periods when case numbers are less than 2 per day in a county are excluded from estimation from case numbers. The generation interval distribution used for estimation is that estimated here. The generation time estimate for the Delta variant is used for dates before Dec. 24, 2021, and for Omicron is used thereafter. Thus the estimates may have a small bias in the case of variants with other transmission intervals.

Credits

Lee Worden, F.I. Proctor Foundation,
Alex Y. Ge, UCSF School of Medicine
Micaela Neus, Woodlamp Technology
Jennifer C. Kwan, Woodlamp Technology
Nathan Murthy, Tesla
Jianda Monique
Eugene T. Richardson, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, Department of Global Health and Social Medicine, Harvard University, Boston, MA
Rae Wannier, F.I. Proctor Foundation, UCSF Dept. of Epidemiology and Biostatistics
Travis Porco, F.I. Proctor Foundation, UCSF Dept. of Epidemiology and Biostatistics

This is not an official UCSF website. The opinions or statements expressed herein should not be taken as a position of or endorsement by the University of California, San Francisco.

Last updated : 2024-04-19 01:11:26 PDT