HomeWorld NewsPfizer Says Its Vaccine Is Highly Effective in 5- to 11-Year-Olds Pfizer Says Its Vaccine Is Highly Effective in 5- to 11-Year-Olds 0 Ahmad October 22, 2021 The company reported that a lower dose of the vaccine was 90.7 percent effective in preventing symptomatic Covid-19 in a clinical trial. Tags World News Newer Older