California's success in limiting the impact of the Covid-19 pandemic - will we continue to behave? was title of a post here on October 6.
Looking at the graph above (click on it to see a larger version), apparently the answer to that question about continued behavior is "no". This is confirmed by news stories such as 11 California counties fall back to more restrictive tiers as COVID-19 surges and California counties return to restrictive Covid rules amid hospitalization surge.
The state instituted for counties a four-tier performance rating system based primarily upon the 7-day Covid-19 positivity rate (percentage of county residents who test positive for the virus of all individuals who are tested) for the week ending 7 days prior.
Yesterday we learned that residents in Amador, Contra Costa, El Dorado, Modoc, Placer, Sacramento, San Diego, Santa Cruz, Siskiyou, Stanislaus, and Trinity counties failed to protect each other resulting in them falling into less favorable tiers. It appears that other counties will see this next week and that no county improved.
Over the last 14 days hospitalizations have increased 31.6% and the number of patients admitted to intensive care units with infections has increased 29.6%.
Indications are that a significant cause is gatherings of family and friends which not only result in spreading within the gathering participants but subsequently also to others. People say they haven't experienced symptoms nor have they tested positively "recently", but that offers little or no protection for getting together with people outside your well-established pod.
How Californians will behave over the holidays - from Thanksgiving through New Year's Day - will determine how many counties will find themselves in the purple at the beginning of the year:
All businesses and schools can do is hope that people will behave. While you might look at the tiers and say the objective is to limit cases, the deeper objective is to limit hospitalizations...and deaths. That is the outcome of bad behavior.