Shares were down 6.6% to $27.91.
The Cambridge, Massachusetts-based company said in a statement that it was making the decision regarding Wednesday's event "as a precautionary measure related to travel amid the evolving novel coronavirus situation."
Moderna said it will continue with the planned webcast of the program, which is scheduled to run from 1 p.m. through 4:15 p.m. ET on Wednesday.
Last week, Moderna surged after it put forward a new coronavirus vaccine for a phase one study.
Moderna said the treatment, known as MRNA-1273, had been shipped to the National Institute of Allergy and Infectious Diseases (NIAID) for a planned U.S.-based study conducted by the National Institutes of Health.
Juan Andres, chief technical operations and quality officer for Moderna, praised the biotech's research team for developing a potential vaccine in "record speed," having just sequenced the virus' genome 42 days earlier.
The company also reported a fourth-quarter loss of $124.2 million, or 37 cents a share, 6 cents narrower the 43-cents-a-share loss that analysts surveyed by Zacks Investment Research had forecast. Moderna missed the mark on revenue, reporting $14.1 million, compared with the $16.9 million that analysts had estimated.
On Tuesday, Inovio Pharmaceuticals (INO) - Get Report shares jumped after the biotech company said it accelerated its timeline for developing a coronavirus vaccine, planning human trials for April and aiming for 1 million doses by the end of the year.
"We plan to begin human clinical trials in the U.S. in April and soon thereafter in China and South Korea, where the outbreak is impacting the most people," J. Joseph Kim, Inovio president and CEO, said in a statement.