Yes you can, that's why elderly people who get influenza strains that they were exposed to as children are much less likely to succumb to it than those who didn't. Lack of full lasting immunity doesn't mean zero immunity.
You can't avoid exposure to a highly contagious respiratory virus. You can't spend the rest of your life masked. And evolution would have make us capable of adapting to being able to handle such viruses. It's not like COVID-19 would be the end of the human race without indefinite masking/social-distancing. Viruses like COVID-19 have emerged innumerable times in the past. Without an innate ability to acquire some level of immunity to such viruses, we wouldn't exist.
COVID-19 was only different in that in 2019, at risk demographics like the elderly population, had no prior exposure to it.
You get COVID-19 every couple of months - with or without prior illness or vaccination! This is not the case with measles, which has a proven vaccine with few and minor side effects!
This is no different than the coronaviruses that cause the common cold. The infections get progressively milder until, at about the 5th infection, exposure no longer leads to infection.
You can't avoid exposure to a highly contagious respiratory virus. You can't spend the rest of your life masked. And evolution would have make us capable of adapting to being able to handle such viruses. It's not like COVID-19 would be the end of the human race without indefinite masking/social-distancing. Viruses like COVID-19 have emerged innumerable times in the past. Without an innate ability to acquire some level of immunity to such viruses, we wouldn't exist.
COVID-19 was only different in that in 2019, at risk demographics like the elderly population, had no prior exposure to it.