Harvard is asking students not to return to campus after its spring break amid coronavirus concerns. In a message to faculty and students on Tuesday, the historic American university said it was moving to virtual teaching for both graduate and undergraduate classes in a bid to stop the spread of the novel corona across campus. “These past few weeks have been a powerful reminder of just how connected we are to one another – and how our choices today determine our options tomorrow,” president Larry Bacow said. The university's goal is to complete the transition by March 23, it added in the statement posted on its website. "We are transitioning over the course of the next few days to non-essential gatherings of no more than 25 people," Mr Bacow added. The move follows other educational institutions making adjustments due to the global outbreak. Columbia suspended classes for two days after an individual linked to the school was exposed to the virus, while Princeton is moving classes online starting March 23. The news came as the top US public health official warned that the country’s outbreak of coronavirus was likely to get worse. US Surgeon General Jerome Adams said people should assess their personal circumstances when deciding whether to cancel travel plans or avoid public gatherings. The virus, which can cause a sometimes fatal flu-like respiratory illness, has steadily spread in the United States this week, disrupting life and spooking investors who worry that a contraction in economic activity could trigger a recession. "Not every community has an outbreak going on right now, but people should know that this is likely to get worse before it gets better," Mr Adams said in an interview on ABC's "Good Morning America" program. A total of 755 confirmed cases of the coronavirus were confirmed nationwide as of Tuesday morning, according to a tally by Johns Hopkins University. There have been 26 coronavirus-related deaths in the country, most of them in Washington state. The Trump administration has been criticized for a slow response to the public health crisis and is under growing pressure to do more to help workers and companies hurt by the outbreak and to boost investors' confidence in the economy. After US stock indexes recorded their biggest one-day selloff since 2008 on Monday, President Donald Trump said his administration would take "major" steps to gird the economy and discuss a possible payroll tax cut with congressional Republicans on Tuesday. He did not provide details but said a news briefing would be held on Tuesday.