Dynamics of antibody response to BNT162b2 vaccine after six months: a longitudinal prospective study

• Published in: The Lancet regional health. Europe Vol. 10; p. 100208
• Main Authors: Naaber, Paul, Tserel, Liina, Kangro, Kadri, Sepp, Epp, Jürjenson, Virge, Adamson, Ainika, Haljasmägi, Liis, Rumm, Anna Pauliina, Maruste, Regina, Kärner, Jaanika, Gerhold, Joachim M., Planken, Anu, Ustav, Mart, Kisand, Kai, Peterson, Pärt
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2021; Elsevier
• Subjects: adverse effects; age; dynamics of the immune response; Research Paper; SARS-CoV-2 mRNA vaccine; dynamics of the immune response; adverse effects; SARS-CoV-2 mRNA vaccine; age
• ISSN: 2666-7762; 2666-7762
• DOI: 10.1016/j.lanepe.2021.100208

SARS-CoV-2 mRNA vaccines have proven high efficacy, however, limited data exists on the duration of immune responses and their relation to age and side effects. We studied the antibody and memory T cell responses after the two-dose BNT162b2 vaccine in 122 volunteers up to 6 months and correlated the findings with age and side effects. We found a robust antibody response to Spike protein after the second dose. However, the antibody levels declined at 12 weeks and 6 months post-vaccination, indicating a waning of the immune response over time. At 6 months after the second dose, the Spike antibody levels were similar to the levels in persons vaccinated with one dose or in COVID-19 convalescent individuals. The antibodies efficiently blocked ACE2 receptor binding to SARS-CoV-2 Spike protein of five variants of concern at one week but this was decreased at three months. 87% of individuals developed Spike-specific memory T cell responses, which were lower in individuals with increased proportions of immunosenescent CD8+ TEMRA cells. We found antibody response to correlate negatively with age and positively with the total score of vaccination side effects. The mRNA vaccine induces a strong antibody response to SARS-CoV-2 and five VOCs at 1 week post-vaccination that decreases thereafter. T cell responses, although detectable in the majority, were lower in individuals with higher T cell immunosenescence. The deterioration of vaccine response suggests the need to monitor for the potential booster vaccination.