Many countries in Africa do only very, very, very few tests for COVID.

[more data on this in our database: https://ourworldindata.org/explorers/coronavirus-data-explorer?zoomToSelection=true&time=latest&pickerSort=asc&pickerMetric=location&Metric=Tests&Interval=7-day+rolling+average&Relative+to+Population=true&Align+outbreaks=false&country=IND~COD~ZAF~ZWE~ZMB~KEN~ETH~SSD~UGA~NGA~MOZ~MDG~NAM~TGO~GHA~CIV~SEN~MAR~TUN~USA~DEU~FRA~CHL~ITA]">https://ourworldindata.org/explorers...

The chart above showed the latest data on daily tests.

This is the number of cumulative tests since the beginning of the pandemic.

[also on this metric you find more data in our database: https://ourworldindata.org/explorers/coronavirus-data-explorer?zoomToSelection=true&time=latest&pickerSort=asc&pickerMetric=location&Metric=Tests&Interval=Cumulative&Relative+to+Population=true&Align+outbreaks=false&country=IND~COD~ZAF~ZWE~ZMB~KEN~ETH~SSD~UGA~NGA~MOZ~MDG~NAM~TGO~GHA~CIV~SEN~MAR~TUN~USA~DEU~FRA~CHL~ITA~DNK]">https://ourworldindata.org/explorers...

While I generally think that changes in the positive-rate are a good way to monitor whether a country tests adequately I& #39;m not convinced this is the case for all countries, especially for poor countries.

It could also be that only very few people have the chance to get tested.