Quantifying the incidence of severe-febrile-illness hospital admissions in sub-Saharan Africa

Abstract

Severe-febrile-illness (SFI) is a common cause of morbidity and mortality across sub-Saharan Africa (SSA). The burden of SFI in SSA is currently unknown and its estimation is fraught with challenges. This is due to a lack of diagnostic capacity for SFI in SSA, and thus a dearth of baseline data on the underlying etiology of SFI cases and scant SFI-specific causative-agent prevalence data. To highlight the public health significance of SFI in SSA, we developed a Bayesian model to quantify the incidence of SFI hospital admissions in SSA. Our estimates indicate a mean population-weighted SFI-inpatient-admission incidence rate of 18.4 (6.8-31.1, 68% CrI) per 1000 people for the year 2014, across all ages within areas of SSA with stable Plasmodium falciparum transmission. We further estimated a total of 16,200,337 (5,993,249-27,321,779, 68% CrI) SFI hospital admissions. This analysis reveals the significant burden of SFI in hospitals in SSA, but also highlights the paucity of pathogen-specific prevalence and incidence data for SFI in SSA. Future improvements in pathogen-specific diagnostics for causative agents of SFI will increase the abundance of SFI-specific prevalence and incidence data, aid future estimations of SFI burden, and enable clinicians to identify SFI-specific pathogens, administer appropriate treatment and management, and facilitate appropriate antibiotic use.

Fig 1. Final fitted relationship between incidence of IPD admissions for severe-febrile-illness (all ages) and estimated prevalence of community-acquired febrile illness (<5 years of age).

The median of the final fitted relationship is represented by the black line, with 68% and 95% credible intervals overlain in increasingly light grey. The overlain points are the observations of the 45 country-years of the incidence of severe-febrile-illness (all ages) versus the national estimated prevalence of community-acquired fever (<5 years of age).

Fig 2. Incidence rate (per 1000 people) of SFI-IPD admissions for severe-febrile-illness in 2014 for each sub-Saharan African country within areas of stable P. falciparum malaria transmission.

Fig 3. Incidence rate (per 1000 people) of 2014 IPD admissions for severe-febrile-illness due to all illnesses other than severe malaria (but including admissions for uncomplicated malaria) for each sub-Saharan African country within areas of stable P. falciparum transmission.

Estimates for severe malaria IPD admissions were unavailable for Equatorial Guinea, South Africa, South Sudan, and eSwatini, thus these countries were not included in this section of the analysis.

Fig 4. Incidence rate (per 1000 people) of 2014 IPD admissions for severe malaria (not including uncomplicated malaria) for each sub-Saharan African country within areas of stable P. falciparum malaria transmission.

These estimates were produced by Camponovo et al. [46]. Estimates for severe malaria IPD admissions were unavailable for Equatorial Guinea, South Africa, South Sudan, and eSwatini, thus these countries were not included in this section of the analysis.

Fig 5. The proportion of 2014 IPD admissions for severe-febrile-illness that were causally due to illnesses other than severe malaria for each sub-Saharan African country within areas of stable P. falciparum transmission.

Illnesses other than severe malaria include admissions for uncomplicated malaria. Estimates for severe malaria IPD admissions were unavailable for Equatorial Guinea, South Africa, South Sudan, and eSwatini, thus these countries were not included in this section of the analysis.