CAMBRIDGE, Mass. - Moderna said Thursday it believes the highly contagious delta variant of the coronavirus will lead to an increase in breakthrough infections among vaccinated people as they begin moving indoors during the upcoming colder months.The company said its two-dose COVID-19 vaccine remained 93% effective at preventing symptomatic disease up to six months after the second shot, citing data recently analyzed from its large clinical trial.
By comparison, Pfizer-BioNTech said last week that its COVID-19 vaccine efficacy declined to around 84% after six months.But Moderna officials believe such protection will begin "to wane and eventually impact vaccine efficacy" amid the ongoing circulation of the delta strain."We believe that.