Editor’s note: Kent Sepkowitz is a physician and infectious disease expert at Memorial Sloan Kettering Cancer Center in New York. CNN —At long last, the Covid-19 pandemic has entered its whimper phase. Last week, the World Health Organization decided to end the Covid-19 global health emergency. The US public health emergency is scheduled to end on Thursday, and beginning the following day, vaccination against Covid-19 will no longer be required for non-US travelers entering the States. Infectious diseases don’t ever really go away; they just change a little, then change some more till one day, they return bigger and fiercer than ever.

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