The Moderna vaccine is very effective. Moderna’s initial Phase 3 clinical data in December 2020 showed about 95% efficacy. This figure has changed over time. At six months after vaccination, the Moderna vaccine was shown to have efficacy of 90% against infection and more than 95% against developing a severe case, according to the company. In addition, while both Pfizer and Moderna still are considered highly effective, several recent studies showed Moderna to be more protective. One study published in The New England Journal of Medicine found the Moderna vaccine to be 96.3% effective in preventing symptomatic illness in health care workers compared to 88.8% for Pfizer.
SOURCE: https://www.yalemedicine.org/news/covid-19-vaccine-comparison (Yale Medicine)