Study suggests persons who recover from COVID-19 may need one vaccine dose On By Sola Ogundipe Those who have had COVID-19 may only need one vaccine dose, a new study suggests People who have recovered from COVID-19 had a robust antibody response after the first mRNA vaccine dose, but a little immune benefit after the second dose, according to new research from the Penn Institute of Immunology. The findings, published in Science Immunology, suggest only a single vaccine dose may be needed to produce a sufficient antibody response. The team found that those who did not have COVID-19 — called COVID naïve — did not have a full immune response until after receiving their second vaccine dose, reinforcing the importance of completing the two recommended doses for achieving strong levels of immunity.