Onondaga County confirmed 21 new cases of coronavirus Wednesday, the largest single-day jump in the county.

The novel coronavirus causes COVID-19, a respiratory disease that has infected over 470,900 people and killed over 21,200 globally. New York state has confirmed over 33,000 cases of the virus.

The county has confirmed 81 total cases of COVID-19 as of Wednesday afternoon, County Executive Ryan McMahon said at a media briefing. 5% of all COVID-19 tests conducted in the county have been positive, he said.

“We know we’re going to have some busy days coming up,” McMahon said at Wednesday’s county COVID-19 briefing, “and we have one”

Ten of the county’s patients are hospitalized, with three in critical condition, McMahon said. Over 248 people are under mandatory isolation and quarantine, he said. 

41% of the county’s COVID-19 patients are under 40 years old, McMahon said. Twenty patients in the county are in their 20s, the age demographic with the most cases.

“We really need people in this demographic to really reflect on their behavior,” McMahon said.