COVID-19 is an emerging, rapidly evolving situation.
Get the latest public health information from CDC:

Get the latest research information from NIH: Menu
Open or close the search fields display
7993 Studies found for: subjects AND Double-blind AND baseline

A similar map is available for all studies in

Click on the map below to show a more detailed map (when available) or search for studies (when map not available).

Map Legend
Region Name Number of Studies
World 7,993
Africa [map] 431
Central America [map] 334
East Asia [map] 1,499
Japan 558 [studies]
Europe [map] 2,800
Middle East [map] 599
North America 4,881
Canada [map] 1,399 [studies]
Mexico 518 [studies]
United States [map] 4,644 [studies]
North Asia [map] 925
Pacifica [map] 848
South America [map] 733
South Asia [map] 297
Southeast Asia [map] 431

Click on a [map] link to show a map of that region.

Click on a [studies] link to search within your current results for studies in that region. Use the back button to return to this list and try another region.

Studies with no locations are not included in the counts or on the map.

Studies with multiple locations are included in each region containing locations.