Moderna's Covid vaccine may NOT stop spread of infection:
Moderna's chief medical officer Tal Zaks told Axios the firm does not have data that shows whether their vaccine prevents people from spreading the virus
Moderna announced earlier this month its shot is 94.5% effective at preventing people from getting sick or severely ill from coronavirus in trials
But because the company did not test asymptomatic participants it doesn't know whether vaccinated people can be silent carriers and spreaders, Zaks said
He added that he believes the vaccine should prevent viral spread - but doesn't have the data to prove it
