Keeping COVID-19 in check will likely require periodic boosters

Between natural infection and a global vaccination campaign, most people now have some immunity against the virus that causes COVID-19. This widespread immunity hasn’t stopped people from getting infected, but it has dampened the massive waves of illness and death that roiled the globe in the early years of the pandemic. Keeping the virus in check requires maintaining this level of immunity, a difficult task because the virus is constantly spinning off new variants that can partially evade antibodies elicited by vaccines and prior infections.