“These numbers show that the vaccine is working extraordinarily well to prevent infection, illness and death in almost everyone vaccinated,” L.A. County Public Health Director Barbara Ferrer said. Of the 3.3 million L.A. County residents fully vaccinated as of May 7, only 933 — or 0.03% — later tested positive for the coronavirus, including people who showed no symptoms but were tested anyway because of workplace requirements, Ferrer said. Furthermore, only 71 fully vaccinated residents, or 0.002%, were later hospitalized with so-called breakthrough infections. Twelve residents, or 0.00036% of fully vaccinated people, died.