Twitter, the social media giant, announced Wednesday that it would close its New York and San Francisco offices just two weeks after they reopened.A spokesperson stated that the decision was made after careful review of the CDC's updated guidelines and taking into account current conditions.Twitter has decided to close its offices in New York City and San Francisco, as well as to halt future office reopenings. This is effective immediately. The spokesperson said that they were continuing to monitor local conditions and making necessary changes to ensure the safety and health of our Tweeps.Initialy, the company reopened these offices on July 12. The company declined to disclose the headcount for each office.This week, the CDC recommended that people who have been fully vaccinated wear masks indoors in areas with high Covid transmission rates. There are also concerns about the contagious Delta variant.TechCrunchs Brian Heater reported today that Sundar Pichai, Google CEO, announced that employees will need to be vaccinated before they can return to work. This letter was sent as part of a larger one to Google/Alphabet employees. It also stated that the company would be extending its work from home policy until October 18th, as the COVID-19 Delta variant continues to sweep the globe.Lori Goler (VP of People at Facebook) confirmed that a similar policy was in place for the social media giant.TechCrunchs also inquired about the matter by Amazon, which responded that they strongly encouraged all Amazon employees and contractors, to get vaccinated as soon COVID-19 vaccines were available.