Vaccines have shown themselves to be the best defense against a serious case of COVID-19: According to the Centers for Disease Control and Prevention, unvaccinated adults were about 13 times more likely to be hospitalized with the disease than vaccinated adults as of late November.
But vaccines and the antibodies they generate are just one piece of the puzzle when it comes to fighting off the coronavirus. The immune system has other sets of defenders that find and kill infected cells, then preserve a living record of the virus, bacteria or other infectious agent so the body can respond faster the next time it's under assault.
And speed is essential, said E. John Wherry, director of the University of Pennsylvania's Institute for Immunology.
