Two people died of the flu in the latest week of statistics released by the Monroe County public health department.
Both deaths were people older than 75, according to the report, which runs through Jan. 25. They bring the total death toll of this flu season to four.
The first local death of the season was a child younger than 4.
"As a general rule, the very young and the very old are especially prone to severe complications, including death" from the flu, said Emil Lesho, the health care epidemiologist at Rochester Regional Health.
Hospitals have been implementing visitor restrictions incrementally as the flu spreads through the Rochester region.
Rochester Regional Health, which put restrictions in place in at Rochester General Hospital and Unity Hospital in Greece on Dec. 31, had restricted visitors at all five of its hospitals by the end of January.
No deaths were recorded at this time last season, and the number of confirmed cases was much lower.
This flu season in upstate New York has been characterized by the prevalence of influenza B, a strain that normally appears much later in the season.
"Everything about the flu is unpredictable sometimes, from year to year. It's just its very nature that it's different every year," Lesho said.
Lesho said those differences arise from small mutations that accumulate over time. "That's the reason why we need to get the flu vaccine every year."
Still, he and other public health officials have said those differences shouldn’t change how people approach flu prevention.
"Get your flu shot. Wash your hands. Stay home if you're sick. Try not to go to work or to school so that you're not spreading it around," Ontario County public health director Mary Beer told WXXI News last month.