Google is postponing a return to the office for most workers until mid-October and rolling out a policy that will eventually require everyone to be vaccinated once its sprawling campuses are fully reopened in an attempt to fight the spreading Delta variant.

In an email sent to Google’s more than 130,000 employees, CEO Sundar Pichai said the company is now aiming to have most of its workforce back to its offices beginning Oct 18 instead of its previous target date of Sept 1. The decision also affects tens of thousands of contractors who Google intends to continue to pay while access to its campuses remains limited, according to an AP report.

“This extension will allow us time to ramp back into work while providing flexibility for those who need it,” Pichai wrote.