Influenza-associated Pediatric Mortality
2004 Case Definition

Clinical Description

An influenza-associated death is defined for surveillance purposes as a death resulting from a clinically compatible illness that was confirmed to be influenza by an appropriate laboratory or rapid diagnostic test. There should be no period of complete recovery between the illness and death. Influenza-associated deaths in all persons aged <18 years should be reported.

A death should not be reported if:

1. There is no laboratory confirmation of influenza virus infection.
2. The influenza illness is followed by full recovery to baseline health status prior to death.
3. The death occurs in a person 18 years or older.
4. After review and consultation there is an alternative agreed upon cause of death.

Laboratory Criteria For Diagnosis

Laboratory testing for influenza virus infection may be done on pre- or post-mortem clinical specimens, and include identification of influenza A or B virus infections by a positive result by at least one of the following:

• Influenza virus isolation in tissue cell culture from respiratory specimens;
• Reverse-transcriptase polymerase chain reaction (RT-PCR) testing of respiratory specimens;
• Immunofluorescent antibody staining (direct or indirect) of respiratory specimens;
• Rapid influenza diagnostic testing of respiratory specimens;
• Immunohistochemical (IHC) staining for influenza viral antigens in respiratory tract tissue from autopsy specimens;
• Four-fold rise in influenza hemagglutination inhibition (HI) antibody titer in paired acute and convalescent sera*.

Confirmed

A death meeting the clinical definition that is laboratory confirmed.

Laboratory or rapid diagnostic test confirmation is required as part of the case definition; therefore, all reported deaths will be classified as confirmed.