The data represented in this graph are dynamic and may change over time.

Since March 20, the Cambridge Public Health Department (CPHD) has provided data regarding COVID-19 case counts based on the date that the Massachusetts Public Health Department (MDPH) reported the case to CPHD (known as report date).

Beginning March 31, 2020, CPHD began providing COVID-19 case counts based on the onset time -- the date of a positive diagnosis -- which is preferable for studying disease patterns over time. Both sets of data provide the same number of total cases. CPHD often receives onset time (positive COVID-19 diagnosis) after the report date. Thus, the graph displaying onset time is recommended as a representation of the case counts per day.

Daily case counts reflect the total number of cases to date, including active and recovered individuals.