Pfizer and Moderna’s COVID-19 vaccines may provide protection lasting for years, a new study says.

The study, which monitored 41 healthy participants from the St. Louis metropolitan area who received both doses of either the Pfizer or Moderna vaccine over several weeks, found germinal center B cells, or structures where mature cells mutate their antibody genes during a normal immune response to an infection, that “remained at or near their peak frequency 15 weeks after immunization in 8 of the 10 participants sampled at that time point.” The study also noted that “antigen-specific GC B cells have been found to persist for at least one year.”