CDC Urges Flu Vaccinations as Pediatric Deaths Rise CDC Director Dr. Brenda Fitzgerald said of the 30 U.S. children who've died from the flu this winter season, 85 percent were not vaccinated. Dr. Brenda Fitzgerald, CDC Director The CDC reported that 32 states have had cases of the H3N2 influenza strain, which is one of the most severe forms of the virus. According to the CDC, the vaccine is only 30 percent effective against this particular strain, but it would decrease the severity of symptoms and number of days in the hospital.