Testing showed a 12-year-old girl in Bergen County, who died in January, had influenza.
Health Department spokeswoman Donna Leusner tells The Record newspaper the girl had underlying medical conditions that made her more vulnerable to complications of the flu.
Officials also linked influenza to the deaths of a 14-year-old boy in Ocean County and an 8-month-old boy in Camden. Both had underlying conditions.
No other conditions were found in a 14-year-old boy in Westfield who died on the flu.
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