New numbers released on Wednesday show 19 people have now died of coronavirus in Connecticut and the state has 875 confirmed cases.
The information was posted on a Department of Public Health website.
The 257 new cases and seven new deaths are both the largest single-day jumps since the crisis began in Connecticut.
The numbers of new cases are expected to rise significantly.
"If we assume 10-percent of our population will get COVID-19 in the first wave, that’s 350,000 people between now and the next 8 to 10 weeks," state epidemiologist Dr. Matthew Cartter said.
He said it is not possible yet to know when the coronavirus epidemic would peak in Connecticut.
Here is how the new numbers break down by county:
- Fairfield County: 546
- New Haven: 127
- Hartford County: 116
- Litchfield County: 33
- Middlesex County: 15
- New London County: 9
- Tolland County: 27
- Windham County: 2
To help prevent the spread of the virus, the governor asked all non-essential businesses and not-for-profits to prohibit all in-person functions.