He may be correct...it hasn't done wonders for cold and flu.
Well... not so fast. There are many types of the "flu", and there are many corona viruses. Herd immunity does happen with flu in certain instances. For example, why didn't the Spanish Flu that killed 20 million+ in 1917-18 come around again until the Fort Dix outbreak in the 1970s? Because virtually everyone alive that survived that pandemic had antibodies. By the 1970s, that generation was dropping away opening the door for a return.
Why hasn't the Asian flu of 1957 or the Hong Kong flu of 1968-9 returned with a vengeance? Same reason. H1N1 has not been a recurring health issue in a decade. Why not?
Here's a hint:
"The 2009 H1N1 Pandemic: A New Flu Virus Emerges
The (H1N1)pdm09 virus was very different from H1N1 viruses that were circulating at the time of the pandemic. Few young people had any existing immunity (as detected by antibody response) to the (H1N1)pdm09 virus, but nearly one-third of people over 60 years old had antibodies against this virus, likely from exposure to an older H1N1 virus earlier in their lives."
Another verification of the herd immunity concept. That, by the way if from the CDC.
https://www.cdc.gov/flu/pandemic-resources/2009-h1n1-pandemic.htmlLook, no one wants to contract this virus, but unless an effective vaccine is developed quickly it will circulate until enough people contract it and develop antibodies to break the transmission. That is how the Spanish Flu, Asian Flu, and Hong Kong Flu pandemics burned themselves out and have not returned. It was not through vaccines. None were available.