Because the earliest confirmed cases of COVID date to late 2019, scientists added the “-19” to the end of the name to make it more specific.
https://blogs.webmd.com/public-health/20200713/why-is-it-called-covid19
Illness caused by SARS-CoV-2 was termed COVID-19 by the WHO, the acronym derived from “coronavirus disease 2019.” The name was chosen to avoid stigmatizing the virus’s origins in terms of populations, geography, or animal associations.
https://www.medscape.com/answers/2500114-197404/why-is-coronavirus-infection-called-covid-19
In simple terms-COVID 19 stands for, Corona (CO) Virus (VI) Disease (D) and 19(2019) the year that the virus first hit.
It was given this name by the World Health Organisation, who said: “Having a name matters to prevent the use of other names that can be inaccurate or stigmatising.”...
Since it was first detected in Wuhan, China in December 2019, the outbreak has rapidly evolved, with the WHO labelling COVID-19 as a global pandemic...
https://www.thesun.co.uk/news/11245785/coronavirus-covid-19/
IOW Global “wokeness”