(CBS/CNN) — Microsoft is joining the growing list of companies that are requiring workers to get vaccinated.

The tech firm said Tuesday that employees, vendors and guests entering Microsoft’s buildings in the US will be required to show proof of vaccination beginning in September.

READ MORE: Coronavirus In Massachusetts: Today's Developments

“As we have done since the beginning of the pandemic, we continue to closely track new developments and adapt our plans as this situation evolves, keeping employee health and safety top of mind,” the company said in a statement.

The Redmond, Washington-based company also pushed back the full reopening of its US offices to no earlier than October 4. Offices in the US were previously expected to open fully on September 7. Working parents with children too young to receive a vaccine and caregivers of people who are immunosuppressed will be able to work from home until January.

Microsoft has a sales office in Burlington, Massachusetts.

The company has more than 180,000 global employees, with around 100,000 in the US.

The recent increase in Covid-19 cases due to the spread of the Delta variant is causing many companies to rethink their reopening plans. More businesses in Massachusetts are starting to announce vaccination requirements for workers.

The Newton-Needham Regional Chamber took a survey of about 450 member businesses. One in four said they’re planning vaccination mandates.

READ MORE: Hurley: Even In Defeat, Tom Brady Just Delivers

Google, which has about 2,000 Massachusetts employees and an office in Cambridge, has announced it’s requiring employee vaccinations. So has Mintz law firm, with hundreds of employees based out of Boston’s Financial District.

Microsoft said employees with a medical condition or other protected reason not to be vaccinated can get an accommodation.

Microsoft’s flexible work plan allows most employees to work remotely up to 50% of the time without manager approval.

CEO Satya Nadella said in an interview with CNN Business last week that the company will continue to review data and evaluate its return-to-work policies.

“People will vote with their feet,” said Nadella. “So one of the other things that I also want us to be is very data-driven versus dogmatic in any policy we create. Not just in terms of the opening, but even the next year.”

(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. CNN’s Kathryn Vasel contributed to this report.)

MORE NEWS: Boston City Workers Given Additional Week To Show Proof Of COVID Vaccination