Spike-antibody responses to COVID-19 vaccination by demographic and clinical factors in a prospective community cohort study

Abstract

Vaccination constitutes the best long-term solution against Coronavirus Disease-2019; however, vaccine-derived immunity may not protect all groups equally, and the durability of protective antibodies may be short. We evaluate Spike-antibody responses following BNT162b2 or ChAdOx1-S vaccination amongst SARS-CoV2-naive adults across England and Wales enrolled in a prospective cohort study (Virus Watch). Here we show BNT162b2 recipients achieved higher peak antibody levels after two doses; however, both groups experience substantial antibody waning over time. In 8356 individuals submitting a sample ≥28 days after Dose 2, we observe significantly reduced Spike-antibody levels following two doses amongst individuals reporting conditions and therapies that cause immunosuppression. After adjusting for these, several common chronic conditions also appear to attenuate the antibody response. These findings suggest the need to continue prioritising vulnerable groups, who have been vaccinated earliest and have the most attenuated antibody responses, for future boosters.

Fig. 1. S-antibody levels over time following the first dose (left) and the second dose (right) of COVID-19 vaccination.

Geometric means and 95% confidence intervals of Spike-antibody (U/ml) for each week since receiving first and second doses of vaccination, stratified by vaccine type (blue = ChAdOx1-S; pink = BNT162b2).

Fig. 2. Dose 2 S-antibody levels linear regression forest plot.

Beta coefficients and 95% confidence intervals, which are displayed as point estimates and associated error bars, derived from adjusted linear regression models for the effect of each clinical risk factor (investigated using a separate model) on log(n) S-antibody levels (U/ml) at ≥28 days after Dose 2. Each model controls for age, sex, ethnicity, vaccine type, dose interval and time since vaccination. Numbers included in each clinical group are as follows: Type 2 Diabetes n = 411, Type 1 Diabetes n = 46, Stroke n = 131, Severe respiratory n = 436, Neurological n = 168, Mental ill-health n = 119, Liver condition n = 144, Ischaemic heart disease n = 374, Inflammatory conditions n = 608, Immunosuppression Steroid long course n = 114, Immunosuppression MAB n = 67, Immunosuppression DMARD n = 194, Hypertension n = 2208, Heart failure n = 40, Haematological (non-malignancy) n = 52, COPD = 244, Clinically vulnerable n = 2319, Clinically extremely vulnerable n = 1144, Chronic viral (HBV, HCV, HIV) n = 45, Chronic kidney disease n = 101, Cancer Non-Haematological n = 666, Cancer Haematological n = 80, BMI underweight n = 82, BMI overweight n = 2619, BMI obese n = 1464, Asthma n = 1375.