Ever since Santa Clara County reported the first patient with the coronavirus in the Bay Area earlier this year, the disease has spread throughout all nine counties in the region, with the number of confirmed cases escalating at a rapid pace. Since officials issued a shelter-at-home order, cases in the Bay Area jumped from 798 on March 17 to 154,162 on Dec. 1, with Santa Clara County accounting for about a fifth of the region’s patients and a quarter of the region’s 1,969 deaths. San Mateo County has reported the fifth-highest number of cases in the region after Santa Clara, Alameda, Contra Costa and San Francisco counties. County health leaders have said the number of confirmed cases is expected to rise as more testing becomes available. Palo Alto Online, the Mountain View Voice and the Almanac have put together this series of charts to help you understand the proliferation of COVID-19 infections on the Peninsula. The charts, which can only be viewed from a Google Chrome browser, will be updated weekly on Tuesdays. Editor’s note: Data on cases, deaths and testing are incomplete due to a problem with the state’s reporting system for communicable diseases.

SANTA CLARA COUNTY

According to data from the county Public Health Department, men and women have been equally vulnerable to infection.  

Men accounted for 50% of the 35,457 confirmed cases and 53% of the 482 deaths reported in Santa Clara County on Dec. 1.

Women accounted for 50% of the cases and 47% of all deaths reported on Dec. 1.

SAN MATEO COUNTY

As of Nov. 30, women accounted for 50% of the county’s 14,614 confirmed cases and 50% of the county’s 170 deaths while men accounted for 50% of all cases and 50% of all deaths.

CASES AND DEATHS BY AGE

Santa Clara and San Mateo counties are also tracking coronavirus cases and deaths by age.

In both counties, residents in every age group, from those 20 years old and younger to those 90 years and older, have been infected by the virus.

In Santa Clara and San Mateo counties, people ages 20-29 represent the largest segment of the population infected with the virus.

The rate of infection does not appear to ascend with age in Santa Clara County, according to the county’s data. Those ages 80 and older have fewer reported cases than those ages 70-79, who have fewer reported cases than those ages 60-69.

In San Mateo County, those in the 30-39 age group represent the second-largest segment of the population infected with the virus.

Those ages 80-89 account for 27% of the deaths in Santa Clara County, followed by those over 90 years old, which represent 22% of the death toll.

In San Mateo County, no one under age 29 has died from the disease, according to statistics from the county Health Department. Those ages 80 to 89 account for 32% of the county’s deaths.

Find comprehensive coverage on the Midpeninsula’s response to the new coronavirus by Palo Alto Online, the Mountain View Voice and the Almanac here.