The CoD as described in hospital registers were retrospectively coded using the ICD-10-CM codes. Cause-specific mortality proportions were derived as the fraction of total deaths possibly associated to specific conditions, using hospital-based ICD-10-CM list diagnoses. Here, owing to the complexity associated with defining infections with pneumococcal aetiology, we limit our perspectives only on pneumococcal-related causes of deaths defined as follow:
ALRI: Diagnosis of pneumonia based on medical declaration as cause of death (i.e. any Acute Lower Respiratory Tract Infection (ALRI) or pneumonia including all diagnosis of ALRI); or
Clinically severe pneumonia: Death resulting from cough or difficult breathing as admission symptoms for child 1-59 months old residing in study area,
A): Clinical pneumococcal infections 
And with either
- A respiratory rate >= 40/minute, or temperature >38.5 C, or refusing to feed, or vomiting and/or lower chest in-drawing
Culture-positive invasive pneumococcal disease
Culture-negative polymerase chain reaction (PCR) or antigen test positive invasive pneumococcal disease
B): Laboratory confirmed infections 
Radiologically confirmed pneumonia i.e. Chest X-ray-Community Acquired Pneumonia compatible with endpoint consolidation
Radiologically confirmed pneumonia i.e. Chest X-ray-Community Acquired Pneumonia with any radiologic abnormality
C): Radiologically confirmed infections 
Clinical cases of pneumococcal infections, which did not meet these criteria, were considered as non-confirmed pneumococcal diseases (unspecified).
D): Causes of deaths not related to pneumococcus 
These included other biologically related causes of under-five deaths apart from those due to pneumococcal infections e.g. Tuberculosis (TB), HIV or malaria and others.
E): Deaths due to injuries 
This consisted of under-five deaths with non-biological causes such as those resulting from injuries or accidents.