key: cord-0697525-vyjvbo0y
authors: Erice, Alejo; Varillas-Delgado, David; Caballero, Cristina
title: Decline of antibody titres three months after two doses of BNT162b2 in non-immunocompromised adults
date: 2021-09-09
journal: Clin Microbiol Infect
DOI: 10.1016/j.cmi.2021.08.023
sha: f30baa6e58a270e4918b5eb23e667dcf4d892824
doc_id: 697525
cord_uid: vyjvbo0y

OBJECTIVE: To assess the antibody response in non-immunocompromised adults after two doses of BNT162b2. METHODS: Prospective, single-centre observational study in non-immunocompromised adults > 18 years of age who received two doses of BNT162b2. The study contemplates analyses of serum samples collected 1.5, 3, 6, 9 and 12 months after the second dose of BNT162b2; results of the 1.5-and 3-months’ time points are presented in this report. Antibodies against the receptor binding domain of the S1 subunit of the spike protein of SARS-CoV-2 (anti-RBD antibodies) were measured using a commercial quantitative immunoassay. A threshold of 4,160 AU/mL (corresponding to an ID(50) of 1:250) was used as surrogate marker for serum neutralizing activity. RESULTS: Of 273 hospital workers who received two doses of BNT162b2, 260/273 (95%) agreed to participate in the study; 2/260 (0.8%) were excluded due to immunocompromised conditions. At the time of this report, 230/258 (89%) subjects [mean age: 46.0 years (SD 11.4 years); 143/230 (62%) females; 87/230 (38%) males] had completed three months of follow-up after the second dose of BNT162b2. Thirty-six (16%) subjects (36/230) had documented mild SARS-CoV-2 infection prior to receiving the first dose of BNT162b2. Median [IQR] anti-RBD titres 1.5 months after vaccination were 9,356 [5,844 - 16,876] AU/mL; three months after vaccination, median anti-RBD titres had declined to 3,952 [2,190 - 8,561] AU/mL (p <0.001). Of 199/230 (86.5%) participants who had anti-RBD titres above 4,160 AU/mL 1.5 months after the second dose of BNT162b2, only 95/230 (41%) maintained anti-RBD titres above this level three months after vaccination (p < 0.001). CONCLUSIONS: The decline of anti-RBD antibodies three months after the second dose of BNT162b2 is of concern because it raises the possibility of a short-lived humoral immunity after vaccination. Booster doses of BNT162b2 might be required to maintain high titers of anti-RBD antibodies over time.

To assess the antibody response in non-immunocompromised adults after two doses 28 of BNT162b2.

Prospective, single-centre observational study in non-immunocompromised adults > 18 32 years of age who received two doses of BNT162b2. The study contemplates analyses 33 of serum samples collected 1.5, 3, 6, 9 and 12 months after the second dose of 34 BNT162b2; results of the 1.5-and 3-months' time points are presented in this report.

Antibodies against the receptor binding domain of the S1 subunit of the spike protein of 37 SARS-CoV-2 (anti-RBD antibodies) were measured using a commercial quantitative 38 immunoassay. A threshold of 4,160 AU/mL (corresponding to an ID 50 of 1:250) was 39 used as surrogate marker for serum neutralizing activity. 

The decline of anti-RBD antibodies three months after the second dose of BNT162b2 59 is of concern because it raises the possibility of a short-lived humoral immunity after (2) participants with anti-RBD antibody titers that were above 4,160 AU/mL 1.5 months after vaccination (n = 199), and 3 months after vaccination (n = 95) (p < 0.001).

Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine

COVID-19 vaccine BNT162b1 elicits human antibody and Th1 cell responses. 233

Safety and immunogenicity of two RNA-Based covid-19 vaccine candidates

Early 240 antibody response in health-care professionals after two doses of SARS-CoV-2 241 mRNA vaccine BNT162b2

COVID-19 in 2021-Continuing Uncertainty

Evidence for antibody as a protective correlate for COVID-19 vaccine

BNT162b2 vaccine breakthough: clinical characteristics of 152 fully 284 vaccinated hospitalized COVID-129 patients in Israel

CoV-2 infection induces long-lived bone marrow plasma cells in humans

SARS-CoV-2 mRNA vaccines induce persistent human germinal centre 293 responses

Immunological memory to SARS-CoV-2 assessed for up to 8 months after 297 infection

BNT162b2 vaccine induces neutralizing antibodies and poly-specific T cells in 301 humans