Prevalence in News Media of Two Competing Hypotheses about COVID-19 Origins.

The COVID-19 pandemic has been one of the most disruptive and painful phenomena of the last few decades. As of July 2021, the origins of the SARS-CoV-2 virus that caused the outbreak remain a mystery. This work analyzes the prevalence in news media articles of two popular hypotheses about SARS-CoV-2 virus origins: the natural emergence and the lab-leak hypotheses. Our results show that for most of 2020, the natural emergence hypothesis was favored in news media content while the lab-leak hypothesis was largely absent. However, something changed around May 2021 that caused the prevalence of the lab-leak hypothesis to substantially increase in news media discourse. This shift has not been uniformed across media organizations but instead has manifested itself more acutely in some outlets than others. Our structural break analysis of daily news media usage of terms related to the laboratory escape hypothesis provides hints about potential sources for this sudden shift in the prevalence of the lab-leak hypothesis in prestigious news media. [ABSTRACT FROM AUTHOR]