COVID-19 symptoms and the Delta variant

With the Delta variant now driving surges of COVID-19 cases worldwide, researchers are examining whether it's causing different symptoms from earlier variants and how it's experienced by vaccinated and unvaccinated people.

Severe breakthrough infections of COVID-19 remain uncommon, but a growing number of Americans are testing positive after being fully vaccinated, with some describing symptoms unlike those that marked earlier COVID waves. "I started having flu-like symptoms Saturday night and went to the doctor this morning," Senator Lindsey Graham tweeted earlier this month, adding that he felt "like I have a sinus infection and suffered "mild symptoms." He thought that without the vaccine, "it would have been a lot worse."