| Abstract: | To determine clinical and epidemiologic differences between influenza caused by
different virus types and subtypes, we identified patients and tested specimens.
Patients were children and adults hospitalized with confirmed influenza and severe
acute respiratory illness (SARI) identified through active, prospective,
hospital-based surveillance from 2009–2012 in South Africa. Respiratory
specimens were tested, typed, and subtyped for influenza virus by PCR. Of 16,005 SARI
patients tested, 1,239 (8%) were positive for influenza virus. Patient age and
co-infections varied according to virus type and subtype, but disease severity did
not. Case-patients with influenza B were more likely than patients with influenza A
to be HIV infected. A higher proportion of case-patients infected during the first
wave of the 2009 influenza pandemic were 5–24 years of age (19%) than were
patients infected during the second wave (9%). Although clinical differences exist,
treatment recommendations do not differ according to subtype; prevention through
vaccination is recommended. |
