"Universities and research institutes embrace Python and R for their statistical analyses," he continues. "Lots of statistics and data mining needs to be done to find a vaccine for the COVID-19 virus. As a consequence, statistical programming languages that are easy to learn and use, gain popularity now."
Tiobe's rankings are based on search-engine results related to programming-language queries, which some developers question as a valid measure of a language's popularity.
Exactly what's behind R's bounce-back on Tiobe's index isn't clear, but it seems at least to suggest that there are core groups for whom R is popular and practical. It also discredits Tiobe's theory that R was on the losing end of consolidation in the market for statistical programming languages.
Backing up Jansen's hunch that COVID-19 vaccine research is driving R's popularity, StackOverflow research in 2017 found R was the second-most visited tag from universities behind Python. It also found that the two largest groups who use R are academics from social sciences and biology, followed closely by the healthcare industry.