Table 1

Six of the 10 WHO Blueprint priority diseases have significant diagnostic gaps

WHO Blueprint priority disease4	Fatality rate	Recent outbreaks	Diagnostic need (red: critical, yellow: important; green: unaddressed)*5	Situation overview5
CCHF	10%–40%38	Pakistan, 2010.39		No established reference test. Very limited availability of commercial assays, with very low usage and limited performance data. No WHO prequalified diagnostic test.
Filoviruses (Ebola and Marburg)	24%–90%40 41	West Africa, 2013–2016 and DRC 2017 and 2018 (Ebola).10 Uganda and Kenya, 2017 (Marburg).42		Recent high-profile outbreaks resulted in international focus and funding, which has enabled the development and introduction of critical diagnostics. Additional work is needed to improve current diagnostics, develop POC tests and ensure reliable availability. Additional work is also needed to ensure regulatory approval beyond WHO EUAL.
Filoviruses (Ebola and Marburg)	24%–90%40 41		Lassa fever		1–15%43	Annual recurring outbreaks in West Africa.44	No WHO-approved diagnostics and limited commercially available tests, none of which are easily deployable in the settings needed.
MERS-CoV	~35%45	Saudi Arabia, 2013–2018. South Korea, 2015.46		Limited availability of validated assays, restricted to highly complex tests. Lack of POC diagnostics.
SARS	~10%47	Global, 2003.47		Recent high-profile outbreaks resulted in international focus and funding, which has enabled the development and introduction of critical diagnostics. Additional work is needed to improve current diagnostics, develop POC tests and ensure reliable availability.
SARS	~10%47	Global, 2003.47	Nipah and henipaviral diseases		~30%48	Bangladesh, 2004.49 India, 2018.50	No WHO-approved diagnostics and limited commercially available tests, none of which are easily deployable in the settings needed.
Rift Valley fever	<1%51	Republic of Niger, 2016.51		No WHO-approved diagnostics and limited commercially available tests, none of which are easily deployable in the settings needed.
Zika virus disease	Not fatal52	South and North America, 2015–2016.29		Recent high-profile outbreaks resulted in international focus and funding, which has enabled the development and introduction of critical diagnostics. Additional work is needed to improve current diagnostics, develop POC tests and ensure reliable availability. Additional work is needed to ensure regulatory approval beyond WHO EUAL.
Zika virus disease	Not fatal52	South and North America, 2015–2016.29	Disease X				Need for diagnostic platforms that can rapidly adapt and support diagnostics for unknown pathogens.

*Red/critical: diagnostics needed but not currently available or validated; yellow/important: diagnostics currently under development; green/unaddressed: diagnostics available but may need improvement.
CCHF, Crimean-Congo haemorrhagic fever; EUAL, Emergency Use Assessment and Listing; MERS-CoV, Middle East respiratory syndrome coronavirus; POC, point of care; SARS, severe acute respiratory syndrome.