minimus: (quote): "Funny thing, my girlfriend at the end of 2019 developed what the doctors called “the flu”. She had respiratory issues suddenly and they prescribed an inhaler."
It's impossible (without tests) to identify the respiratory problems experienced by your girlfriend.
However, it may have been covid19. The USA based journal The Scientist published this report, under the heading. "New Evidence Shows COVID-19 Was in US Weeks Before Thought." (The Scientist-21/17/2021)
Here's more from the article: "In a study published in Clinical Infectious Diseases June 15, researchers analyzed blood collected between January 2 and March 18, 2020, and found antibodies to SARS-CoV-2 in samples from nine people in five US states, meaning that the virus was likely present in the US in late 2019.
“We suspected that there were probably cases that preceded the ones that were diagnosed and confirmed. This is very suggestive that there were probably multiple exposures prior to those initial cases,” says Ashley St. John, an infectious disease researcher at Duke-NUS Medical School in Singapore who was not involved in the study. "