https://www.mercurynews.com/2020/05/23/coronavirus-new-cases-spike-in-san-mateo-contra-costa-counties/

As state-wide data showed 90,000 people across California have tested positive for coronavirus, new confirmed infections in San Mateo and Contra Costa counties jumped significantly Saturday over recent daily averages, health officials reported.

While San Mateo had no new deaths Saturday, it saw 50 new cases, bringing its total number of confirmed infections to 1,833. During the previous seven days, the daily average was 30 new cases. The number of people recorded as dead from the virus in San Mateo County remained at 76.