Background According to the WHO, over 300 people drown every week in Nigeria. However, this figure excludes drownings caused by watercraft accidents and flood disasters. Research indicates that the WHO vastly underestimates drowning mortality because of this. Understanding the true extent of the drowning crisis in Nigeria is crucial to engaging stakeholders to implement prevention strategies.

Aim To assess the extent of underreporting of drowning mortality by the WHO in Nigeria.

Methods Vanguard news online database was searched for articles reporting fatal drowning incidents between 2009–2019. The causes or circumstances of each incident were extracted to create a sample of drowning victims. Causes of drowning were coded according to the ICD-10, with inclusion of all-cause drowning codes. Drownings caused by codes classified by the WHO as drowning deaths were compared to all-cause drowning deaths to estimate the extent of underreporting.

Results 346 drowning victims were sampled from 98 articles. 54.9% (n=175) of drownings were caused by watercraft accidents. Flood disasters, intentional causes and land transport accidents caused 5.3% (n=17), 1.5% (n=5) and 1.3% (n=4) of drownings respectively. The cumulative proportion of drownings caused by activities or circumstances not classified by the WHO as drowning deaths was 63.0% (n=201).

Conclusion & Learning Outcomes The WHO underestimates the drowning burden in Nigeria by at least 50%. All-cause drowning codes must be included in mortality statistics to state the true extent of the global drowning crisis. Watercraft accidents are a major cause of drowning in Nigeria; immediate targeted prevention strategies are needed