While the state doesn't track each and every case of confirmed influenza, there's no doubt this flu season in New Jersey is more severe than last.

Piotr Marcinski, ThinkStock

Based on only samples from schools, nursing homes, hospitals and other areas, the latest report from the state Department of Health points to at least 8,243 positive flu tests since early October. The number of positive tests was 765 the same week last year.

Influenza activity has been "high" in every New Jersey county since the start of 2017, according to state data.

The department said it's impossible to tell how much of the flu increase is due to better reporting or an increase in the actual illness. More labs are submitting data to the state this year.

The Centers for Disease Control and Prevention announced this week the flu vaccine has been 48 percent effective, compared to 59 percent last flu season.

"Having these nice days to be outside may give you a little bit of a reprieve, but it certainly doesn't mean you can't still get influenza. It is circulating," said Jennifer Crawford, supervisor of Ocean County Health Department's communicable disease unit.

Data show 553 confirmed influenza cases in Ocean County so far. And those are just the cases reported to the state.

Crawford said her unit has regular interaction with school nurses, and they're seeing increases in student absenteeism, in line with what they usually see this time of year.

At 1,542, Bergen County came in with the greatest amount of confirmed cases, based on samples, followed by Passaic and Monmouth counties.