• What would the immune response to the first dose of an mRNA vaccine be in patients who’ve already tested positive for SARS-CoV-2 in the past compared to patients who are seronegative at the time of the first dose?
• Two groups: one seronegative at the time of the first dose of an mRNA vaccine and one seropositive at the time of the first dose of an mRNA vaccine, 110 study participants in total
• The seronegative group was found to show relatively low SARS-CoV-2 antibody production within 9-12 days after vaccination, while the seropositive group was found to quickly create high antibody titers a few days after the first dose of an mRNA vaccine
• The antibody concentration of those participants who had antibodies before mRNA vaccine injection were found to be 10-45 times as high as those without antibodies before mRNA vaccine injection
• It was found that antibody titers of the seronegative group increased by a factor of 3 after receiving the second vaccine dose, but the antibody titers of the seropositive group showed no significant increase after receiving the second dose!
• Overall, it was discovered that a single dose of the mRNA vaccine in seropositive patients created a rapid immune response, with postvaccination antibody concentrations close to or greater than those found in seronegative patients who received both doses.