The focus here is on Western Massachusetts, other states have departments of health that provide locally relevant information (March 7, 2020 Update)
(1) Massachusetts Department of Public Health (Mass DPH):
https://www.mass.gov/guides/information-on-the-outbreak-of-2019-novel-coronavirus-covid-19
Information about the current status of the disease in Massachusetts and elsewhere and instructions for voluntary quarantines by people who have recently returned to the Commonwealth from known affected areas.
(2) Western Massachusetts Hospitals:
Cooley Dickinson Hospital:
https://www.cooleydickinson.org/2020/03/coronavirus-q-a/
Berkshire Health Systems:
https://www.berkshirehealthsystems.org/body.cfm?id=4261&fr=true
Baystate Medical Center:
https://www.baystatehealth.org/covid19
(3) Centers for Disease Control (CDC):
Seasonal flu: https://www.cdc.gov/flu/index.htm
Covid-19: https://www.cdc.gov/coronavirus/2019-ncov/index.html
(4) Johns Hopkins Bloomberg School of Public Health/Center for Health Security
Covid-19: http://www.centerforhealthsecurity.org/resources/COVID-19/
Wide range of diverse information including opportunity to sign up for daily newsletter. Fact sheets, travel advisories, also included are links to newspaper coverage and political aspects of what has been happening.
(5) European Resources:
World Health Organization (WHO):
Covid-19: https://www.who.int/emergencies/diseases/novel-coronavirus-2019
The EU Center for Disease Control (info about situation in European countries): https://www.ecdc.europa.eu/en/novel-coronavirus-china/sources-updated
(6) For data nerds:
World-o-Meters: world and country-by-country statistics from a great number of perspectives including data on testing. This one looks quite accurate:
https://www.worldometers.info/coronavirus/
Corona Virus Dashboard (prepared by Avi Schiffmann. a high schooler in Washington State), a compendium of statistics about the numbers of cases and their status throughout the world plus preparedness info and other data-driven material:
https://ncov2019.live/data?fbclid=IwAR1zIUd0oR7PlxyNCn3c4Oc7ooBuilJ5zonHiM61TkV5N-Lh5M9JaJLom3o
(7) Miscellaneous sources:
Various online news and information sources have daily coverage from different perspectives
The BBC: https://www.bbc.com/news/world
CNN: https://www.cnn.com/
Wall Street Journal (may have paywall): https://www.wsj.com/
The Week: https://theweek.com/
The New York Times (may have paywall): https://www.nytimes.com/
The Washington Post (may have paywall): https://www.washingtonpost.com/