Clinical and immunological benefits of full primary COVID-19 vaccination in individuals with SARS-CoV-2 breakthrough infections: A prospective cohort study in non-hospitalized adults

Hybrid immunity by two COVID‐19 mRNA vaccinations and one breakthrough infection provides a robust and balanced cellular immune response as basic immunity against severe acute respiratory syndrome coronavirus 2

“…32,33 In our study, significant elevated levels of 1). 15 Samples were allocated into three groups according to their COVID-…”

“…This study corroborates that healthy individuals who had received two mRNA vaccinations and had experienced BTI may have immunological benefits from a robust B-cell response by the generation of S-specific high avidity antibodies compared to those who either had a single vaccine dose or were not vaccinated as recently published. 15 Accumulation of somatic mutations in S-specific memory B-cells 16 generating antibodies with high binding capacity against S-protein antigens may be accelerated by complete primary vaccination in combination with BTI rather than by one exposure to S-protein during primary infection. In a previous study, we have demonstrated that individuals who had at least three exposures not only increased the concentration of S-specific IgG antibodies, but also improved avidity and neutralization capacity.…”

“…Peripheral venous blood samples were obtained after 1 week (w1), 2 weeks (w2), 3-7 weeks (w3-7), and 17-24 weeks (w17-24) after PCR-confirmed SARS-CoV-2 infection collecting samples and data from April 13, 2021 until November 25, 2021 in Bavaria, Germany, covering the third (prevalent VOC Alpha) and fourth (Delta) SARS-CoV-2 waves in Germany (Table 1). 15 For comparison, a group of individuals with a booster dose (F+Booster, n = 37) without BTI were included in this study. 10 The study was performed according to the principles of the declaration of Helsinki 1964 and its later amendments and approved by the local ethics committees (protocol number 100/21_z).…”

“…Effectiveness in preventing reinfection is an important point to be mentioned and of relevance for clinical practice. From our previous publication,15 we calculated a vaccine effectiveness of 94.2% (n = 3 BTI in 52 partially vaccinated individuals) and 100% (n = 0 BTI in fully vaccinated 101 individuals) in the vaccinated groups P+BTI and F+BTI, respectively, until w17-24 compared to 91.3% (n = 4 of 46 unvaccinated individuals) in group U who experienced a further SARS-CoV-2 infection in the observation period (p < 0.001, comparison between group F+BTI and U). In this study, two of the U group experienced BTI in the observation period between w5-7 and w14-24 (effectiveness 78.9%), none in the P+BTI and F+BTI group.…”