WINDOW ROCK, Ariz. (AP) — Navajo Nation President Jonathan Nez has signed an executive order requiring all government workers on the tribe’s vast reservation to have a booster shot. Nez also says tribal health officials have changed how the term “fully vaccinated” is defined by making it two doses of the COVID-19 vaccine plus a booster shot. The actions come after a record number of COVID cases have been reported on the reservation that covers 27,000 square miles and extends into parts of Arizona, New Mexico and Utah. Tribal health officials reported 525 new cases Friday, the most in a single day since the pandemic began almost two years ago. That number topped the 405 cases reported Thursday. The tribe reported 62 cases Saturday, but no reported deaths from the virus in the last three days.