Global Trends of Seroprevalence and Universal Screening Policy for Chagas Disease in Donors: a systematic review and meta-analysis
Authors: Kim Jenny Yeon Hee , Ledien Julia , Rodriguez-Monguí Eliana , Dobson Andy , Basáñez María-Gloria , Cucunubá Zulma M. 
Published: December 2019

Background

Screening for Trypanosoma cruzi among blood and organ donors is essential to reduce Chagas disease transmission. The World Health Organization (WHO) has prioritised curtailing transmission in blood banks (BBs) and transplantation centres (TCs) by 50% by 2025 and 100% by 2030. This study aims to update the situation on T. cruzi screening strategies in BBs and TCs to evaluate the evolution of seroprevalence and the achievement of screening milestones globally.

Methods

We used published articles and government reports on seroprevalence data and screening policies in BBs and TCs across the world. We conducted meta-analyses of T. cruzi seroprevalence estimates by who region, endemicity status, and country, and used meta-regression to identify the covariates influencing the estimates. Publication bias and sensitivity analyses were also conducted.

Results

Based on 99 studies and reports and found a global pattern of increased universal screening policies (USPs) in BBs from 1990 to 2018. We found information for 50 countries, of which 44 (88%) have implemented USPs and 21 (42%) achieved 100% coverage by 2015. Out of the 21 Chagas-disease endemic countries, 20 are in advanced USPS stages, and 18 achieved 100% coverage by 2015. Latin America (LA) was the first region to start USPS since the 1990s and 19 countries are in advanced stages of implementation and by 2015 there is evidence of 100% coverage in 15 LA countries. In the Caribbean Region, USPs are still in early implementation stages and by 2015 only five out of 24 countries have achieved 100% coverage. Outside Latin America and the Caribbean, there are USPs only in the USA, which initiated in 2007 and with 100% coverage in 2016. In Europe, there are no USPs, but some countries have implemented selective screening of at-risk donors in the UK, Spain, France and Switzerland. Whereas Sweden and Italy have implemented a deferral system. For TCs, national guidelines have been produced in some European countries since the 2000s; in the USA, USPs started since 2002, but 100% coverage is yet to be achieved. There is a global decrease in T. cruzi seroprevalence among blood donors from the 1970s to 2010s, particularly in endemic countries, where the T. cruzi pooled seroprevalence decreased from 2.42% (95% CI 0.75%-7.53%) in the 1970s to 0.38% (95% CI 0.30%-0.60%) in the 2010s. Seroprevalence in non-endemic countries has remained relatively stable between 1990s and 2010s around 0.01% (95% CI 0.01%-0.03%). Country and decade were identified as the two major predictors of seroprevalence in BBs. Data on TCs was scarce.

Interpretation

Despite global progress in T. cruzi screening policies, both USPs and 100% coverage are yet to be achieved. Seroprevalence in BBs have decreased in endemic countries, likely due to a combination of vector control, increased USPs and voluntary donation, and improved diagnosis. To achieve the proposed WHO goals by 2025 and 2030, USPs in TCs must become available in all endemic countries. In BBs, USPs should be a priority in the Caribbean region as well as non-endemic countries where migration from endemic countries is important.