RWE for 2nd MSB COVID-19 ARDS P3 Trial, page-217

Tbe Pooh Bear China flu. Like Spanish flu, Hong Kong flu and all the rest...

It will become another seasonal flu.

Yes, probably, the flu, Influenza, kills quite a few annually, the right vaccines are usually made each year but they are only so effective, then there are the pandemics.

Spanish flu
"It is estimated that about 500 million people or one-third of the world’s population became infected with this virus. The number of deaths was estimated to be at least 50 million worldwide with about 675,000 occurring in the United States."

1957-1958 Pandemic (H2N2 virus)
The estimated number of deaths was 1.1 million worldwide and 116,000 in the United States.

1968 Pandemic (H3N2 virus)
The estimated number of deaths was 1 million worldwide and about 100,000 in the United States.

2009 H1N1 Pandemic (H1N1pdm09 virus)
CDC estimated that 151,700-575,400 people worldwide died from (H1N1)pdm09 virus infection during the first year the virus circulated.** Globally, 80 percent of (H1N1)pdm09 virus-related deaths were estimated to have occurred in people younger than 65 years of age. This differs greatly from typical seasonal influenza epidemics, during which about 70 percent to 90 percent of deaths are estimated to occur in people 65 years and older.

From https://www.cdc.gov/flu/pandemic-resources/basics/past-pandemics.html

Sorry but herd immunity doesn't really matter after the right, or wrong, mutation happens. We need more than vaccines.