Twitter has announced it is closing its two biggest offices in New York City and San Francisco, which reopened just two weeks ago, citing concerns about the dynamics of the pandemic. “After careful consideration of the CDC’s updated guidelines, and in light of current conditions, Twitter has made the decision to close our opened offices in New York and San Francisco as well as pause future office reopenings, effective immediately,” a Twitter spokesperson said in a statement. The Centers for Disease Control and Prevention (CDC) on July 27 revised its guidance on masking, citing the threat of the Delta variant, with the agency now recommending fully vaccinated people to mask up indoors in public places if they’re in areas of “substantial or high transmission.” According to the CDC, most of California falls into that category, though a handful of counties are at “moderate” and “low” levels. The bulk of New York counties are …