Coronavirus outbreak: US varsities suspend regular classes, switch to online teaching amid disease scare

At least a dozen colleges and universities across the United States, including schools in the University of California, have cancelled in-person classes and switched to teaching their courses online as the battle against the novel coronavirus in the United States intensifies.

The cancellations have been focused on states hardest hit by Covid-19 cases, including California, New York and Washington state after the virus infected more than 800 people in the US and killed at least 28 according to official counts cited by Al Jazeera.

On Tuesday, Harvard University in Cambridge, Massachusetts, asked its students not to return to campus after its spring break, which begins on Saturday and said it would move to virtual teaching by March 23.

"The decision to move to virtual instruction was not made lightly," the university said in a statement.

"The goal of these changes is to minimize the need to gather in large groups and spend prolonged time in close proximity with each other in spaces such as classrooms, dining halls, and residential buildings," it read.

Columbia University, Princeton University, Stanford University, Ohio State University, the University of Southern California and the University of Washington have all announced similar "social-distancing" measures.

Princeton University in New Jersey said all lectures, seminars, and courses would be moved online after its spring recess next week. Online instruction there will last until at least April 5.

Stanford University, located in California's Santa Clara County, which currently has dozens of confirmed cases of the coronavirus, cancelled all in-person classes for the final two weeks of its winter semester.

The Ohio State University also suspended in-person classes through at least March 30.

The virus - which originated in Wuhan, China, last year - has spread to more than 110 countries, areas or territories worldwide and infected over 100,000. More than 4,000 have died as a result of the virus.

For most people, the infectious respiratory disease causes only mild or moderate symptoms such as fever and cough and the infected recover within weeks.

For others, especially older adults and people with health problems, it can cause more severe illness, including pneumonia.