key: cord-1043108-qx7dqdjo authors: Otter, A. D.; D'Arcangelo, S.; Whitaker, H.; Hewson, J.; Foulkes, S.; Atti, A.; Cole, M.; Linley, E.; Tonge, S.; Hettiarachchi, N.; Sajedi, N.; Calbraith, D.; Norman, C.; de Lacy, E.; Price, L.; Stewart, S.; Cromey, L.; Corrigan, D.; SIREN study group,; Rowe, C.; Brown, C.; Islam, J.; Semper, A.; Hopkins, S.; Hall, V.; Brooks, T. title: Determinants of SARS-CoV-2 anti-spike antibody levels following BNT162b2 vaccination: cross-sectional analysis of 6,000 SIREN study participants date: 2022-04-21 journal: nan DOI: 10.1101/2022.04.21.22274025 sha: b9d99ba99e05d497a21ede6bee969d03a55007ac doc_id: 1043108 cord_uid: qx7dqdjo Background: Understanding immunological responses to SARS-CoV-2 vaccinations is integral to the management of SARS-CoV-2. We aimed to investigate determinants of antibody response to the BNT162b2 vaccine. Methods: A cross-sectional analysis of anti-spike binding antibodies in serum samples from healthcare workers after one or two doses. Post-vaccination interval was restricted to [≥]21 days after dose 1, [≥]14 days after dose 2. The primary outcome was anti-S titres with explanatory variables dose, previous infection, dosing interval, age, ethnicity, and comorbidities. Multivariable linear regression was also conducted. Results: Participants (n=5,871) included 3,989 post-dose 1, 1,882 post-dose 2. In SARS-CoV-2 infection naive, 99.65% seroconverted after dose 1 and >99.9% seroconverted after dose 2. Geometric mean anti-S titre in the naive cohort was 75.48 Binding Antibody Units/ml after dose 1, 7,049 BAU/ml after dose 2. Anti-S titres were higher in those with previous infection (2,111 BAU/ml post-dose 1, 16,052 BAU/ml post-dose 2), and increased with time between infection and vaccination: 3 months 1,970 (1,506-2,579) vs 9 months; 13,759 (8,097-23,379). Longer dosing intervals increased antibody response post-dose 2: 11-fold higher with a longer interval (>10 weeks) than those with shorter intervals, across all age-groups. Younger participants had higher mean titres (>2.2-fold higher). Multivariable regression modelling corroborated the above associations, and also found higher titres associated with being female or from an ethnic minority but lower titres among immunocompromised participants. Conclusion: The number of antigen exposures and timing between vaccinations plays a significant role in the magnitude of the post-vaccination antibody response, with implications for long-term protection and post-booster antibody responses. quantitative, as described elsewhere 17 , with the presence of anti-nucleocapsid antibodies 130 used as a proxy for probable previous infection in the absence of a previous PCR positive. 131 The Roche anti-spike assay is quantitative, producing results between 0.4 U/ml and 225,000 132 U/ml, with automatic dilutions performed to achieve sample results within the quantitative 133 range (0.4 to 250 U/ml). The Roche anti-spike assay has been fully calibrated to the NIBSC Outcomes were stratified by dosing interval, age, gender, ethnicity and comorbidities. For 147 analysis on existing health conditions, participants were classified into three categories based 148 on data provided within their enrolment questionnaire. Specific health conditions were 149 categorised: immunosuppression (participants with immune system cancer, rheumatology 150 disease, transplant recipients, those with spleen conditions or other autoimmune conditions 151 not listed here), chronic respiratory disease (asthma, chronic obstructive pulmonary disease, 152 or other chronic respiratory diseases), and chronic non-respiratory diseases (diabetes, 153 obesity, chronic-neurological disease, dementia, other cancers, chronic heart disease, chronic 154 kidney disease, liver disease and HIV). 155 All statistics were performed on log transformed anti-spike antibody values (in BAU/ml), unless 157 otherwise stated, using R (version 4.0.2), with regression analysis performed in STATA 158 (version 14.2). Mean antibody titres are reported as geometric means. Two-sample t-tests 159 were used for comparisons between groups. Normal error multivariable linear regression 160 models were fitted to log antibody levels (separate models for 28+ days post dose 1 and 21+ 161 days post dose 2), including covariates such as days since dose, age group, sex, ethnicity, 162 existing health conditions and for dose 2 only, dosing schedule group. Regression coefficients 163 were exponentiated for interpretation as adjusted geometric mean ratios. The interval in days 164 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) HCWs ( Figure 2) ; there was a ~2-fold decrease between the 25-34 years (115 BAU/ml, 95% 218 CI 105 -126) and >54 years (55.51 BAU/ml, 95% CI 50.7 -60.78) age groups (2.03, 95% CI 219 1.78-2.32). Similarly, a ~2.3-fold decrease was observed between the 25-34 (12,288 BAU/ml; 220 95% CI 9,140 -16,520) and >54 years (5,367 BAU/ml, 95% CI 4,691 -6,140) age groups 221 post-dose 2 (1.63, 95% CI 1.34-1.98). In contrast, those with previous infection, showed no 222 significant differences between any of the age groups post-dose 1 or post-dose 2 ( Figure 1) . 223 The geometric mean antibody titres increased with longer intervals between doses, with a 9-224 fold increase after an interval of >10 weeks compared with >2 and <4 weeks, with this trend 225 consistent across all age groups (Table 2 ). In general, younger participants had significantly 226 higher antibody responses than older participants with the same vaccine interval, with the 227 exception of the >2 and <4-week dose interval (due to low numbers in the <25 and 25-34 age 228 groups) (Table 2) . Thus, participants aged >54 years with a dosing interval of >2 and <4 weeks 229 had a geometric mean antibody titre of 1,303 BAU/ml (n= 25, 95% CI 713.28 -2382), whereas 230 those aged <25 years with a >10 week dosing interval had a geometric mean antibody titre of 231 21,472 BAU/ml (n= 10, 95% CI 14,435 -31,940), a ~16.5 fold difference (Table 2) . Antibody 232 titres for each of the dosing interval groups were also analysed in relation to the time elapsed 233 between vaccination and sample date, to prevent the data being skewed by sampling bias 234 (Supplementary Table 3 provided a baseline sample 4-5 weeks, 6-7 weeks or 8-9 weeks after their second dose, the 236 significant difference between >2 and <4 weeks and >10 weeks dosing intervals remained, 237 highlighting that the observed difference in antibody titres was due to the dosing interval and 238 not due to sample collection bias. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 21, 2022. ; https://doi.org/10.1101/2022.04.21.22274025 doi: medRxiv preprint infection, and all tested on the same anti-spike and anti-nucleocapsid assays, this dataset has 313 provided a highly robust, cross-sectional analysis of determinants of the antibody response 314 following vaccination. As this study used a fully quantitative anti-RBD assay reporting in 315 BAU/ml relative to the 1 st WHO international SAR-CoV-2 immunoglobulin standard 19 The SIREN cohort continues to provide insights into vaccine effectiveness, vaccine 367 responses, reinfections and now vaccination breakthrough infections. With the waning of 368 immunity and increasing vaccine breakthroughs, this cohort will play an essential part in 369 determining why patients develop vaccine breakthrough infections and determining any 370 potential correlates of protection. 371 372 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 21, 2022. ; https://doi.org/10.1101/2022.04.21.22274025 doi: medRxiv preprint Annotated code for this analysis is available at: (https://github.com/SIREN-study/SARS-CoV-374 2-Immunity). The metadata for this analysis will be available to researchers through the Health 375 Data Research UK CO-CONNECT platform and available for secondary analysis. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 21, 2022. ; https://doi.org/10.1101/2022.04.21.22274025 doi: medRxiv preprint A single-dose mRNA vaccine provides a long-term protection for 415 hACE2 transgenic mice from SARS-CoV-2 Antibody response to first BNT162b2 dose in previously SARS-CoV-417 2-infected individuals Antibody Responses after a Single Dose of SARS-CoV-2 mRNA 419 Single-dose administration and the influence of the timing of the 421 booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) 422 vaccine: a pooled analysis of four randomised trials Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine Vaccine BNT162b2 -426 CONDITIONS OF AUTHORISATION UNDER REGULATION 174 Medicines & Healthcare products Regulatory Agency (MHRA) Report Authorisation for Temporary Supply COVID-19 mRNA Vaccine BNT162b2 429 concentrate for solution for injection Department of Health and Social Care ( DHSC ) Annex A: Report to JCVI on estimated efficacy of a single 432 dose of Pfizer BioNTech (BNT162b2 mRNA) vaccine and of a single dose of 433 ChAdOx1 vaccine (AZD1222) England: a large, multicentre, prospective 447 cohort study (SIREN) Differential immunogenicity of BNT162b2 or ChAdOx1 vaccines after 449 extended-interval homologous dual vaccination in older people Time series analysis and mechanistic modelling of heterogeneity 452 and sero-reversion in antibody responses to mild SARS-CoV-2 infection WHO International Standard for anti-SARS-CoV-2 458 immunoglobulin Strong humoral immune responses against SARS-CoV-2 Spike after 460 BNT162b2 mRNA vaccination with a sixteen-week interval between doses Extended interval BNT162b2 vaccination enhances peak antibody 463 generation in older people Immunogenicity of standard and extended dosing intervals of 466 BNT162b2 mRNA vaccine Articles T-cell and antibody responses to first BNT162b2 vaccine 468 dose in previously infected and SARS-CoV-2-naive UK health-care workers: a 469 multicentre prospective cohort study Antibody responses to SARS-CoV-2 vaccines in 45,965 adults from the 484 general population of the United Kingdom Age-related immune response heterogeneity to SARS-CoV-2 486 vaccine BNT162b2 Robust antibody responses in 70-80-year-olds 3 weeks after the 488 first or second doses of Pfizer/BioNTech COVID-19 vaccine Quantitative SARS-CoV-2 anti-spike responses to Pfizer-BioNTech 491 and Oxford-AstraZeneca vaccines by previous infection status Examining the Immunological Effects of COVID-19 Vaccination in 494 Patients with Conditions Potentially Leading to Diminished Immune Response 495 Antibody responses after first and second Covid-19 vaccination in 498 patients with chronic lymphocytic leukaemia Heterologous infection and vaccination shapes immunity against 500 SARS-CoV-2 variants. Science Waning Immune Humoral Response to BNT162b2 Covid-19 Vaccine over 6 Months We thank all SIREN participants for enrolling within the SIREN study and continuing to provide 379 samples. We also thank all staff within the NHS that enable SIREN to operate.