Aug 18 (Reuters) - Cigna Corp (CI.N) said on Wednesday it requires its employees working remotely to be fully vaccinated before entering any U.S. worksite from Sept. 7, as infections from the Delta variant of the coronavirus rise in the country. The health insurer joined a slew of companies such as Centene Corp (CNC.N), Morgan Stanley (MS.N) and Microsoft Corp (MSFT.O) across the healthcare, technology and financial sectors in mandating vaccines or tests for employees working from office. read more "It"s clear we need to do more to stop the ongoing spread of COVID-19, and unlike many aspects of the pandemic, keeping our worksites as safe as possible is something we can control," said Dr. Steve Miller, chief clinical officer of Cigna. Employees who must work onsite such as medical care providers and pharmacists should be fully vaccinated or receive two negative COVID-19 tests per week starting on Oct. 18, the company said. Cigna said it plans to reopen offices throughout the fall, but employees who can work from home will continue to have the option to do so.