BACKGROUND:

Estimates of influenza-associated outpatient consultations and hospitalizations are severely limited in low- and middle-income countries, especially in Africa.

METHODS:

We conducted active prospective surveillance for influenza-like illness (ILI) and severe acute respiratory illness (SARI) at 5 healthcare facilities situated in Kinshasa Province during 2013-2015. We tested upper respiratory tract samples for influenza viruses using a reverse transcription polymerase chain reaction assay. We estimated age-specific numbers and rates of influenza-associated ILI outpatient consultations and SARI hospitalizations for Kinshasa Province using a combination of administrative and influenza surveillance data. These estimates were extrapolated to each of the remaining 10 provinces accounting for provincial differences in prevalence of risk factors for pneumonia and healthcare seeking behavior. Rates were reported per 100,000 population.

RESULTS:

During 2013-2015 the mean annual national number of influenza-associated ILI outpatient consultations was 1,003,212 (95% Confidence Incidence [CI]: 719,335-1,338,050 - Rate: 1,205.3; 95% CI: 864.2-1,607.5); 199,839 (95% CI: 153,563-254,759 - Rate: 1,464.0; 95% CI: 1,125.0-1,866.3) among children aged <5 years and 803,374 (95% CI: 567,772-1,083,291 - Rate: 1,154.5; 95% CI: 813.1-1,556.8) among individuals aged ≥5 years. The mean annual national number of influenza-associated SARI hospitalizations was 40,361 (95% CI: 24,014-60,514 - Rate: 48.5; 95% CI: 28.9-72.7); 25,452 (95% CI: 19,146-32,944 - Rate: 186.5; 95% CI: 140.3-241.3) among children aged <5 years and 14,909 (95% CI: 4,868-27,570 - Rate: 21.4; 95% CI: 28.9-72.7) among individuals aged ≥5 years.

CONCLUSIONS:

The burden of influenza-associated ILI outpatient consultations and SARI hospitalizations was substantial and was highest among hospitalized children aged <5 years