The popularity of searches for SARS never went above 7 before late Dec. when cases of pneumonia were already popping up in the news. There was no signficant difference between searches from July 2019 to November 2019. If you look at the same data exactly one year ago in 2018 you'll find that the prevalence of searches for cough and SARs were actually much higher in 2018[0] (prevalences in the 70s and 50s in 2018 vs prevalence that were less than 10 in 2019). So unless you're suggesting Covid-19 actually started in 2018 it seems any correlation between search volume and cases of covid-19 fails to disprove the null hypothesis.

Plus there's the fact that you're looking at data in English for a search engine blocked in China.

[0] https://trends.google.com/trends/explore?date=2018-07-01%202...