According to Moderna, at 3.7 months following administration, MRESVIA RSV vaccine efficacy was reported to be 78.7 percent against RSV illness with two or more symptoms of lower respiratory tract disease (LRTD), and 80.9 percent against RSV illness with three or more symptoms of LRTD. At 8.6 months following administration, MRESVIA RSV vaccine efficacy was reported to be only 62.5 percent against RSV illness with two or more symptoms of LRTD, and 61.1 percent against RSV illness with three or more symptoms of LRTD.
At 8.6 months following vaccine administration, MRESVIA RSV vaccine was reported to have an efficacy of 58.8 percent in persons 60 through 69 years of age, and an efficacy of 78.0 percent in person 70 through 79 years of age. In persons 80 years of age and older, by 8.6 months, MRESVIA RSV vaccine was reported to have an efficacy of -20 percent. A negative efficacy means that individuals who received MRESVIA were more likely to develop RSV than those who received the placebo.
