A dismantled health infrastructure leaves the U.S. incredibly vulnerable, warns infectious-disease expert Michael Osterholm.

NEW YORK — The science of fighting disease has never been stronger. We have the means to detect outbreaks immediately, sequence pathogens in the space of days, and develop new vaccines in just months.

It is five years to the day since Boris Johnson took a deep breath and told the nation that it “must stay at home” to slow the spread of Covid-19. The long lockdown that followed had consequences – in ...