Story highlights 3 out of 4 children who died from the flu had not gotten a flu vaccine

Widespread activity continues through 48 states

(CNN) The deaths of 22 more children from flu-related causes were reported Friday by the US Centers for Disease Control and Prevention in its weekly surveillance report.

Those deaths bring the total number of children reported to have died to 84 since October, when the current flu season began. Three out of four children who died from the flu had not gotten a flu vaccine, the acting director of the CDC said in a Thursday news conference.

"We continue to recommend parents get their children vaccinated even though it's late in the season," Dr. Anne Schuchat said. The season may continue for several more weeks, she added.

Caused by viruses, flu is a contagious respiratory illness with mild to severe symptoms that can sometimes lead to death.

The vaccine's performance in children was "better than we expected," Schuchat said after the release of the CDC's midseason report of estimated vaccine effectiveness rates.

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