Update on the global epidemiology of intussusception: a systematic review of incidence rates, age distributions and case-fatality ratios among children aged <5 years, before the introduction of rotavirus vaccination.

BACKGROUND:In some countries that have introduced oral rotavirus vaccines, a small but elevated risk of intussusception-a rare bowel disorder-has been reported. Updated estimates on the global epidemiology of intussusception are needed to help predict the potential number of intussusception cases that could be caused by the vaccine in different settings. METHODS:We estimated incidence rates, age distributions and case-fatality ratios (CFRs) for intussusception hospital admissions among children aged <5 years, before the introduction of rotavirus vaccines. We included all articles identified in a systematic review between January 2002 and January 2018, and contacted authors for more granular unpublished data on age distributions. RESULTS:We identified 128 articles containing 227 country datasets (61 age distributions, 71 incidence rates and 95 CFRs). The median age of intussusception ranged from 29 weeks in Africa (83% of cases in the first year of life) to 70 weeks in the Western Pacific region (35% of cases in the first year of life). The median (range) annual incidence of intussusception hospital admissions per 100 000 aged <1 year ranged from 34 (13-56) in Africa to 90 (9-380) in the Western Pacific region. We found extreme differences between the CFRs in Africa (1 death in every 10 hospital admissions) and the rest of the world (fewer than 1 death in every 100-2000 hospital admissions). CONCLUSION:Intussusception epidemiology varies by country and region. Understanding and recognizing these differences will be important when assessing the potential number of intussusception cases associated with rotavirus vaccines.