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

Abstract

Background 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. Methods 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. Findings 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. Interpretation 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.

Robust Neutralizing Antibody Responses 6 Months Post Vaccination with BNT162b2: A Prospective Study in 308 Healthy Individuals

“…Our results are consistent with another prospective study including 122 individuals vaccinated with BNT162b2 [9]. A waning humoral response against SARS-CoV-2 was evident at three and six months post vaccination, especially among older individuals [9].…”

“…Our results are consistent with another prospective study including 122 individuals vaccinated with BNT162b2 [9]. A waning humoral response against SARS-CoV-2 was evident at three and six months post vaccination, especially among older individuals [9]. A persistent but declining antibody activity at six months post vaccination has been also reported for the mRNA-1273 [10,11].…”

“…The sustainability of T-cell responses following vaccination is another factor to consider. BNT162b2 induces robust T-cell responses against both wild-type SARS-CoV-2 and variants of concern for at least three months following vaccination [9,17,18].…”

Vaccine-induced humoral and cellular immunity against SARS-CoV-2 at 6 months post BNT162b2 vaccination

“…At 6 months of receiving the second dose of BNT162b2 vaccine, SP-specific IgG decreased markedly, with a mean GMT decreasing from 95.2 at 3 weeks after vaccination to 5.7 at 6 months. A previous report showed a peak at 1 week after 2 doses and a decrease to 7% at 6 months [4]. Our data using the CLEIA method demonstrated a surprising decrease to 1/15 after 3 weeks of vaccination, and the same trend was noted for NT50, which also depicted a marked decrease.…”

Vaccines against COVID-19: Priority to mRNA-Based Formulations

“…These features also keep this format optimal in terms of the design and production of vaccines that might be needed in case variants of SARS-CoV-2 resisting the current vaccine-induced immune response emerge (this is so far not the case even if the beta variant is less well recognized than other variants by mRNA-vaccine-induced antibodies). As the vaccines induced immune response declines over time [54], a third dose more than six months after the second dose is recommended, particularly in elderly people or at-risk groups. In Israel, although a fourth wave of COVID came in summer 2021, it is estimated that, altogether, two thirds of hospitalizations and deaths have been prevented by the mRNA vaccine campaign [55].…”