(CNN) Biotechnology company Moderna believes its vaccine should protect people against Covid-19 for at least a year, a top official told investors Monday.
"Our expectation is that the vaccination should last you at least a year," Moderna's chief medical officer Tal Zaks told the JP Morgan 39th Annual Healthcare Conference.
Both Moderna's and Pfizer/BioNTech's coronavirus vaccines have won emergency use authorization from the US Food and Drug Administration.
Zaks said the company will have to test people to see if adding a third dose -- a boost -- might extend protection. Currently, the vaccine is given as two doses about a month apart. Because both vaccines were only invented within the past year, no one knows how long they'll protect people.
"We'll have to boost people to see how well the boost works," Zaks said. "We think there is an opportunity to boost, especially the ones at high risk, should you need it."