Influence of age, sex, body habitus, vaccine type and anti-S serostatus on cellular and humoral responses to SARS-CoV-2 vaccination (preprint)

Vaccine development targeting SARS-CoV-2 in 2020 was of critical importance in reducing COVID-19 severity and mortality. In the U.K. during the initial roll-out most individuals either received two doses of Pfizer COVID-19 vaccine (BNT162b2) or the adenovirus-based vaccine from Oxford/AstraZeneca (ChAdOx1-nCoV-19). There are conflicting data as to the impact of age, sex and body habitus on cellular and humoral responses to vaccination, and most studies in this area have focused on determinants of mRNA vaccine immunogenicity. Here we studied a cohort of participants in a population-based longitudinal study (COVIDENCE UK) to determine the influence of age, sex, body mass index (BMI) and pre-vaccination anti-Spike (anti-S) antibody status on vaccine-induced humoral and cellular immune responses to two doses of BNT162b2 or ChAdOx-n-CoV-19 vaccination. Younger age and pre-vaccination anti-S seropositivity were both associated with stronger antibody responses to vaccination. BNT162b2 generated higher neutralising and anti-S antibody titres to vaccination than ChAdOx1-nCoV-19, but cellular responses to the two vaccines were no different. Irrespective of vaccine type, increasing age was also associated with decreased frequency of cytokine double-positive CD4+ T cells. Increasing BMI was associated with reduced frequency of SARS-CoV-2-specific TNF+ CD8% T cells for both vaccines. Together, our findings demonstrate that increasing age and BMI associate with attenuated cellular and humoral responses to SARS-CoV-2 vaccination. Whilst both vaccines induced T cell responses, BNT162b2 induced significantly elevated humoral immune response as compared to ChAdOx-n-CoV-19.

Long-term symptom profiles after COVID-19 vs other acute respiratory infections: a population-based observational study (COVIDENCE UK) (preprint)

Summary Background: Long COVID is a well recognised, if heterogeneous, entity. Acute respiratory infections (ARIs) due to other pathogens may cause long-term symptoms, but few studies compare post-acute sequelae between SARS-CoV-2 and other ARIs. We aimed to compare symptom profiles between people with previous SARS-CoV-2 infection, people with previous non-COVID-19 ARIs, and contemporaneous controls, and to identify clusters of long-term symptoms. Methods: COVIDENCE UK is a prospective, population-based UK study of ARIs in adults. We analysed data on 16 potential long COVID symptoms and health-related quality of life (HRQoL), reported in January, 2021, by participants unvaccinated against SARS-CoV-2. We classified participants as having previous SARS-CoV-2 infection or previous non-COVID-19 ARI ([≥]4 weeks prior) or no reported ARI. We compared symptoms by infection status using logistic and fractional regression, and identified symptom clusters using latent class analysis (LCA). Findings: We included 10,203 participants (1343 [13.2%] with SARS-CoV-2 infection, 472 [4.6%] with non-COVID-19 ARI). Both types of infection were associated with increased prevalence/severity of most symptoms and decreased HRQoL compared with no infection. Participants with SARS-CoV-2 infection had increased odds of taste/smell problems and hair loss compared with participants with non-COVID-19 ARIs. Separate LCA models identified three symptom severity groups for each infection type. In the most severe groups (including 23% of participants with SARS-CoV-2, and 21% with non-COVID-19 ARI), SARS-CoV-2 infection presented with a higher probability of memory problems, difficulty concentrating, hair loss, and taste/smell problems than non-COVID-19 ARI. Interpretation: Both SARS-CoV-2 and non-COVID-19 ARIs are associated with a wide range of long-term symptoms. Research on post-acute sequelae of ARIs should extend from SARS-CoV-2 to include other pathogens. Funding: Barts Charity.

Rebound in asthma exacerbations following relaxation of COVID-19 restrictions: a longitudinal population-based study (COVIDENCE UK) (preprint)

BackgroundThe imposition of restrictions on social mixing early in the COVID-19 pandemic was followed by a reduction in asthma exacerbations in multiple settings internationally. Temporal trends in social mixing, incident acute respiratory infections (ARI) and asthma exacerbations following relaxation of COVID-19 restrictions have not yet been described. MethodsWe conducted a population-based longitudinal study in 2,312 UK adults with asthma between November 2020 and April 2022. Details of face covering use, social mixing, incident ARI and moderate/severe asthma exacerbations were collected via monthly on-line questionnaires. Temporal changes in these parameters were visualised using Poisson generalised additive models. Multilevel logistic regression was used to test for associations between incident ARI and risk of asthma exacerbations, adjusting for potential confounders. ResultsRelaxation of COVID-19 restrictions from April 2021 coincided with reduced face covering use (p<0.001), increased frequency of indoor visits to public places and other households (p<0.001) and rising incidence of COVID-19 (p<0.001), non-COVID-19 ARI (p<0.001) and moderate/severe asthma exacerbations (p=0.007). Incident non-COVID-19 ARI associated independently with increased risk of asthma exacerbation (adjusted odds ratio 5.75, 95% CI 4.75 to 6.97) as did incident COVID-19, both prior to emergence of the omicron variant of SARS-CoV-2 (5.89, 3.45 to 10.04) and subsequently (5.69, 3.89 to 8.31). ConclusionsRelaxation of COVID-19 restrictions coincided with decreased face covering use, increased social mixing and a rebound in ARI and asthma exacerbations. Associations between incident ARI and risk of moderate/severe asthma exacerbation were similar for non-COVID-19 ARI and COVID-19, both before and after emergence of the SARS-CoV-2 omicron variant. FundingBarts Charity, UKRI

Influence of vitamin D supplementation on SARS-CoV-2 vaccine efficacy and immunogenicity (preprint)

Background and Aims: Vitamin D deficiency has been reported to associate with impaired development of antigen-specific responses following vaccination. We aimed to determine whether vitamin D supplements might boost immunogenicity and efficacy of SARS-CoV-2 vaccination. Methods: We conducted three sub-studies nested within the CORONAVIT randomised controlled trial, which investigated effects of offering vitamin D supplements at a dose of 800 or 3200 IU per day vs. no offer on risk of acute respiratory infections, including COVID-19, in UK adults with circulating 25-hydroxyvitamin D concentrations under 75 nmol/L. Sub-study 1 (n=2808) investigated effects of vitamin D supplementation on risk of breakthrough SARS-CoV-2 infection following two doses of SARS-CoV-2 vaccine. Sub-study 2 (n=1853) investigated effects of vitamin D supplementation on titres of combined IgG, IgA and IgM (IgGAM) anti-Spike antibodies in eluates of dried blood spots collected after SARS-CoV-2 vaccination. Sub-study 3 (n=100) investigated effects of vitamin D supplementation on neutralising antibody and cellular responses in venous blood samples collected after SARS-CoV-2 vaccination. Results: 1945/2823 (69.3%) sub-study 1 participants received two doses of ChAdOx1 nCoV-19 (Oxford AstraZeneca); the remainder received two doses of BNT162b2 (Pfizer). Vitamin D supplementation did not influence risk of breakthrough SARS-CoV-2 infection (800 IU per day vs. no offer: adjusted hazard ratio 1.28, 95% CI 0.89 to 1.84; 3200 IU per day vs. no offer: 1.17, 0.81 to 1.70). Neither did it influence IgGAM anti-Spike titres, neutralising antibody titres or interferon-gamma concentrations in supernatants of S peptide-stimulated whole blood. Conclusions: Among adults with sub-optimal baseline vitamin D status, vitamin D replacement at a dose of 800 or 3200 IU per day did not influence protective efficacy or immunogenicity of SARS-CoV-2 vaccination. Clinical Trial Registration: ClinicalTrials.gov NCT04579640.

Cohort Profile: Longitudinal population-based study of COVID-19 in UK adults (COVIDENCE UK) (preprint)

Background: Coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is estimated to have caused more than 18 million deaths worldwide as of end-May 2022. Methods: COVIDENCE UK is a longitudinal population-based study that investigates risk factors for, and impacts of, COVID-19 in UK residents aged [≥]16 years. A unique feature is the capacity to support trial-within-cohort studies to evaluate interventions for prevention of COVID-19 and other acute respiratory illnesses. Participants complete a detailed online baseline questionnaire capturing self-reported information relating to their socio-demographic characteristics, occupation, lifestyle, quality of life, weight, height, longstanding medical conditions, medication use, vaccination status, diet and supplemental micronutrient intake. Follow-up on-line questionnaires capturing incident symptoms of COVID-19 and other acute respiratory infections, incident swab test-confirmed COVID-19, doses of SARS-CoV-2 vaccine received, and quality of life are completed at monthly intervals. Results: The study was launched on 1st May 2020 and closed to recruitment on 6th October 2021. A total of 19,981 participants enrolled and consented to 5-year follow-up with medical record linkage. Their mean age was 59.1 years (range 16.0 to 94.4 years), 70.2% were female, and 93.7% identified their ethnic origin as White. Analyses conducted to date have provided key insights into risk factors for SARS-CoV-2 infection and COVID-19 disease, determinants of SARS-CoV-2 vaccine immunogenicity and efficacy, and impacts of COVID-19 on health economic outcomes. The cohort has also supported conduct of a Phase 3 randomised trial-within-cohort study (CORONAVIT) evaluating implementation of a test-and-treat approach to correcting sub-optimal vitamin D status on incidence and severity of acute respiratory infections, including COVID-19. Conclusions: The COVIDENCE UK dataset represents a valuable resource containing granular information on factors influencing susceptibility to, and impacts of, COVID-19 in UK adults. Researchers wishing to access anonymised participant-level data should contacting the corresponding author for further information.

Risk factors for SARS-CoV-2 infection after primary vaccination with ChAdOx1 nCoV-19 or BNT1262b2 and after booster vaccination with BNT1262b2 or mRNA-1273: a population-based cohort study (COVIDENCE UK) (preprint)

Background: Little is known about the relative influence of demographic, behavioural, and vaccine-related factors on risk of post-vaccination SARS-CoV-2 infection. We aimed to identify risk factors for SARS-CoV-2 infection after primary and booster vaccinations. Methods: We undertook a prospective population-based study in UK adults ([≥]16 years) vaccinated against SARS-CoV-2, including data from Jan 12, 2021, to Feb 21, 2022. We modelled risk of post-vaccination SARS-CoV-2 infection separately for participants who had completed a primary course of vaccination (two-dose or, in the immunosuppressed, three-dose course of either ChAdOx1 nCoV-19 [ChAdOx1] or BNT1262b2) and for those who had additionally received a booster dose (BNT1262b2 or mRNA-1273). Cox regression models were used to explore associations between sociodemographic, behavioural, clinical, pharmacological, and nutritional factors and breakthrough infection, defined as a self-reported positive result on a lateral flow or reverse transcription PCR (RT-PCR) test for SARS-CoV-2. Models were further adjusted for weekly SARS-CoV-2 incidence at the local (lower tier local authority) level. Findings: 14,713 participants were included in the post-primary analysis and 10,665 in the post-booster analysis, with a median follow-up of 203 days (IQR 195-216) in the post-primary cohort and 85 days (66-103) in the post-booster cohort. 1051 (7.1%) participants in the post-primary cohort and 1009 (9.4%) participants in the post-booster cohort reported a breakthrough SARS-CoV-2 infection. A primary course of ChAdOx1 (vs BNT182b2) was associated with higher risk of infection, both in the post-primary cohort (adjusted hazard ratio 1.63, 95% CI 1.41-1.88) and in the post-booster cohort after boosting with mRNA-1273 (1.29 [1.03-1.61] vs BNT162b2 primary plus BNT162b2 booster). A lower risk of breakthrough infection was associated with older age (post-primary: 0.96 [0.96-0.97] per year; post-booster: 0.97 [0.96-0.98]), whereas a higher risk of breakthrough infection was associated with lower levels of education (post-primary: 1.66 [1.35-2.06] for primary or secondary vs postgraduate; post-booster: 1.36 [1.08-1.71]) and at least three weekly visits to indoor public places (post-primary: 1.38 [1.15-1.66] vs none; post-booster: 1.33 [1.10-1.60]). Conclusions: Vaccine type, socioeconomic status, age, and behaviours affect risk of breakthrough SARS-CoV-2 infection following a primary schedule and a booster dose.

Correlation between post-vaccination titres of combined IgG, IgA, and IgM anti-Spike antibodies and protection against breakthrough SARS-CoV-2 infection: a population-based longitudinal study (COVIDENCE UK) (preprint)

In this population-based cohort of 7530 adults, combined IgG/A/M anti-Spike titres measured after SARS-CoV-2 vaccination were predictive of protection against breakthrough SARS-CoV-2 infection. Discrimination was significantly improved by adjustment for factors influencing risk of SARS-CoV-2 exposure including household overcrowding, public transport use, and visits to indoor public places.

Determinants of pre-vaccination antibody responses to SARS-CoV-2: a population-based longitudinal study (COVIDENCE UK) (preprint)

Background: Prospective population-based studies investigating multiple determinants of pre-vaccination antibody responses to SARS-CoV-2 are lacking. Methods: We did a prospective population-based study in SARS-CoV-2 vaccine-naive UK adults between May 1 and Nov 2, 2020. Information on 88 potential risk factors was obtained through online questionnaires, and combined IgG/IgA/IgM responses to SARS-CoV-2 spike glycoprotein were determined in dried blood spots. We used logistic and linear regression to estimate adjusted odds ratios (aORs) and adjusted geometric mean ratios (aGMRs) for potential determinants of SARS-CoV-2 seropositivity (all participants) and antibody titres (seropositive participants only), respectively. Results: 1696 (15.2%) of 11,130 participants were seropositive. Factors independently associated with increased risk included frontline health/care occupation (aOR 1.86, 95% CI 1.49-2.33), international travel (1.22, 1.08-1.37), BMI >30 vs <25 kg/m2 (1.22, 1.05-1.42), Asian/Asian British vs White ethnicity (1.65, 1.10-2.47), and alcohol consumption [≥]15 vs 0 units/week (1.26, 1.06-1.49). Light physical exercise associated with decreased risk (0.80, 0.69-0.93, for [≥]10 vs 0-4 h/week). Higher titres associated with frontline health/care occupation (aGMR 1.26, 95% CI 1.13-1.41), international travel (1.10, 1.04-1.16), BMI >30 vs <25 kg/m2 (1.09, 1.01-1.17), and Asian/Asian British vs White ethnicity (1.23, 1.03-1.46); these associations were not substantially attenuated by adjustment for disease severity. Conclusions: Higher alcohol consumption and reduced physical exercise represent new modifiable risk factors for SARS-CoV-2 infection. Recognised associations between Asian/Asian British ethnic origin and obesity and increased risk of SARS-CoV-2 seropositivity were independent of other sociodemographic, clinical, or behavioural factors investigated.

Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of aggregate data from randomised controlled trials (preprint)

Objectives: To assess the overall effect of vitamin D supplementation on risk of acute respiratory infection (ARI), and to identify factors modifying this effect. Design: We conducted a systematic review and meta-analysis of data from randomised controlled trials (RCTs) of vitamin D for ARI prevention using a random effects model. Pre-specified sub-group analyses were done to determine whether effects of vitamin D on risk of ARI varied according to baseline 25-hydroxyvitamin D (25[OH]D) concentration or dosing regimen. Data Sources: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, ClinicalTrials.gov and the International Standard RCT Number (ISRCTN) registry from inception to May 2020. Eligibility Criteria for Selecting Studies: Double-blind RCTs of supplementation with vitamin D or calcidiol, of any duration, were eligible if they were approved by a Research Ethics Committee and if ARI incidence was collected prospectively and pre-specified as an efficacy outcome. Results: We identified 40 eligible RCTs (total 30,956 participants, aged 0 to 95 years). Data were obtained for 29,841 (96.5%) of 30,909 participants in 39 studies. For the primary comparison of vitamin D supplementation vs. placebo, the intervention reduced risk of ARI overall (Odds Ratio [OR] 0.89, 95% CI 0.81 to 0.98; P for heterogeneity 0.009). No statistically significant effect of vitamin D was seen for any of the sub-groups defined by baseline 25(OH)D concentration. However, protective effects were seen for trials in which vitamin D was given using a daily dosing regimen (OR 0.75, 95% CI 0.61 to 0.93); at daily dose equivalents of 400-1000 IU (OR 0.70, 95% CI 0.55 to 0.89); and for a duration of [≤]12 months (OR 0.82, 95% CI 0.72 to 0.94). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (OR 0.94, 95% CI 0.81 to 1.08). Risk of bias within individual studies was assessed as being low for all but two trials. A funnel plot showed asymmetry, suggesting that small trials showing non-protective effects of vitamin D may have been omitted from the meta-analysis. Conclusions: Vitamin D supplementation was safe and reduced risk of ARI, despite evidence of significant heterogeneity across trials. The overall effect size may have been over-estimated due to publication bias. Protection was associated with administration of daily doses of 400-1000 IU vitamin D for up to 12 months. The relevance of these findings to COVID-19 is not known and requires investigation.

Low serum 25-hydroxyvitamin D (25D) levels in patients hospitalised with COVID-19 are associated with greater disease severity: results of a local audit of practice. (preprint)

Objectives: To audit implementation of a local protocol for the treatment of vitamin D deficiency (VDD) among patients hospitalized for Coronavirus Disease 2019 (COVID-19), including an assessment of the prevalence of VDD in these patients, and of potential associations with disease severity and fatality. Design: This was not a study or clinical trial, but rather a retrospective interim audit (Newcastle-upon-Tyne Hospitals Registration No. 10075) of a local clinical care pathway for hospitalized patients with COVID-19-related illness. The Information (Caldicott) Guardian permitted these data to be shared beyond the confines of our institution. Setting: A large tertiary academic NHS Foundation Trust in the North East of England, UK, providing care to COVID-19 patients. Participants: One hundred thirty-four hospitalized patients with documented COVID-19 infection. Main outcome measures: Adherence to local investigation and treatment protocol; prevalence of VDD, and relationship of baseline serum 25(OH)D with markers of COVID-19 severity and inpatient fatality versus recovery. Results: 55.8% of eligible patients received Colecalciferol replacement, albeit not always loaded as rapidly as our protocol suggested, and no cases of new hypercalcaemia occurred following treatment. Patients admitted to ITU were younger than those managed on medical wards (61.1 years +/- 11.8 vs. 76.4 years +/- 14.9, p<0.001), with greater prevalence of hypertension, and higher baseline respiratory rate, National Early Warning Score-2 and C-reactive protein level. While mean serum 25(OH)D levels were comparable [i.e. ITU: 33.5 nmol/L +/- 16.8 vs. Non-ITU: 48.1 nmol/L +/- 38.2, mean difference for Ln-transformed-25(OH)D: 0.14, 95% Confidence Interval (CI) (-0.15, 0.41), p=0.3], only 19% of ITU patients had 25(OH)D levels greater than 50 nmol/L vs. 60.9% of non-ITU patients (p=0.02). However, we found no association with fatality, potentially due to small sample size, limitations of no-trial data and, potentially, the prompt diagnosis and treatment of VDD. Conclusions: Subject to the inherent limitations of observational (non-trial) audit data, analysed retrospectively, we found that patients requiring ITU admission were more frequently vitamin D deficient than those managed on medical wards, despite being significantly younger. Larger prospective studies and/or clinical trials are needed to elucidate the role of vitamin D as a preventive and/or therapeutic strategy for mitigating the effects of COVID-19 infection in patients with VDD.