Cross-Reactive Antibody Responses to Coronaviruses Elicited by SARS-CoV-2 Infection or Vaccination.

BACKGROUND: The newly emerged SARS-CoV-2 possesses shared antigenic epitopes with other human coronaviruses. We investigated if COVID-19 vaccination or SARS-CoV-2 infection may boost cross-reactive antibodies to other human coronaviruses. METHODS: Prevaccination and postvaccination sera from SARS-CoV-2 naïve healthy subjects who received three doses of the mRNA vaccine (BioNTech, BNT) or the inactivated vaccine (CoronaVac, CV) were used to monitor the level of cross-reactive antibodies raised against other human coronaviruses by enzyme-linked immunosorbent assay. In comparison, convalescent sera from COVID-19 patients with or without prior vaccination history were also tested. Pseudoparticle neutralization assay was performed to detect neutralization antibody against MERS-CoV. RESULTS: Among SARS-CoV-2 infection-naïve subjects, BNT or CV significantly increased the anti-S2 antibodies against Betacoronaviruses (OC43 and MERS-CoV) but not Alphacoronaviruses (229E). The prevaccination antibody response to the common cold human coronaviruses did not negatively impact the postvaccination antibody response to SARS-CoV-2. Cross-reactive antibodies that binds to the S2 protein of MERS-CoV were similarly detected from the convalescent sera of COVID-19 patients with or without vaccination history. However, these anti-S2 antibodies do not possess neutralizing activity in MERS-CoV pseudoparticle neutralization tests. CONCLUSIONS: Our results suggest that SARS-CoV-2 infection or vaccination may potentially modulate population immune landscape against previously exposed or novel human coronaviruses. The findings have implications for future sero-epidemiological studies on MERS-CoV.

Tai Chi and aerobic exercise on cancer-related dyspnea in advanced lung cancer patients: A randomized clinical trial.

CONTEXT: Dyspnea, a prevalent and debilitating symptom in patients with advanced lung cancer, negatively affects symptom burden and prognosis. Physical activity has emerged as a promising non-pharmacological intervention for managing dyspnea. OBJECTIVES: This study compared the effectiveness of two widely-recognized physical activity modalities, namely Tai Chi (TC) and aerobic exercise (AE) for treating dyspnea in patients with advanced lung cancer. METHODS: Patients with advanced lung cancer (n=226) were randomized into TC, AE, or control groups. There was no baseline dyspnea requirement for patients. The AE group received two 60-minute supervised sessions and home-based exercises per month, the TC group received 60-minute sessions twice weekly, and the control group received exercise guidelines for 16 weeks. The primary outcome (sleep quality) of the study has been previously reported. In this secondary analysis, we focused on dyspnea outcomes, including overall and lung cancer-specific dyspnea. Assessments were conducted at baseline (T0), 16 weeks (T1), and one year (T2). RESULTS: Compared to the control group, TC significantly improved overall dyspnea at T1 (between-group difference, -8.69; P=0.03) and T2 (between-group difference, -11.45; P=0.01), but not AE. Both AE (between-group difference, -11.04; P=0.01) and TC (between-group difference, -14.19; P<0.001) significantly alleviated lung cancer-specific dyspnea at T2 compared with the control group. CONCLUSION: Both TC and AE alleviate dyspnea severity in patients with advanced lung cancer, and continuous exercise can yield substantial improvements. Due to its multi-component nature, Tai Chi has a greater effect on dyspnea. KEY MESSAGE: In this three-arm trial, we conducted a secondary data analysis to examine the effects of Tai Chi and aerobic exercise on cancer-related dyspnea in patients with advanced lung cancer. Both exercise modalities demonstrated effectiveness in reducing dyspnea severity, with Tai Chi exhibiting greater effect.

Association of nirmatrelvir-ritonavir with post-acute sequelae and mortality in patients admitted to hospital with COVID-19: a retrospective cohort study.

BACKGROUND: Studies have established the short-term efficacy of nirmatrelvir-ritonavir in managing COVID-19, yet its effect on post-COVID-19 condition, especially in patients admitted to hospital, remains understudied. This study aimed to examine the effect of nirmatrelvir-ritonavir on post-COVID-19 condition among patients admitted to hospital in Hong Kong. METHODS: This retrospective cohort study used real-world, territory-wide inpatient records, vaccination records, and confirmed COVID-19 case data from the Hong Kong Hospital Authority and Department of Health, The Government of the Hong Kong Special Administrative Region. Patients aged 18 years and older who tested positive for SARS-CoV-2 between March 11, 2022, and Oct 10, 2023, and who were admitted to hospital with COVID-19 were included. The treatment group included patients prescribed nirmatrelvir-ritonavir within 5 days of symptom onset, excluding those prescribed molnupiravir within 21 days, and the control group had no exposure to either nirmatrelvir-ritonavir or molnupiravir. The outcomes were post-acute inpatient death and 13 sequelae (congestive heart failure, atrial fibrillation, coronary artery disease, deep vein thrombosis, chronic pulmonary disease, acute respiratory distress syndrome, interstitial lung disease, seizure, anxiety, post-traumatic stress disorder, end-stage renal disease, acute kidney injury, and pancreatitis). These outcomes were evaluated starting at 21 days after the positive RT-PCR date in each respective cohort constructed for the outcome. Standardised mortality ratio weights were applied to balance covariates, and Cox proportional hazards regression was used to investigate the relationship between nirmatrelvir-ritonavir and outcomes. FINDINGS: 136 973 patients were screened for inclusion, among whom 50 055 were eligible and included in the analysis (24 873 [49·7%] were female and 25 182 [50·3%] were male). 15 242 patients were prescribed nirmatrelvir-ritonavir during acute COVID-19 and 23 756 patients were included in the control group; 11 057 patients did not meet our definition for the exposed and unexposed groups. Patients were followed up for a median of 393 days (IQR 317-489). In the nirmatrelvir-ritonavir group compared with the control group, there was a significantly lower hazard of post-acute inpatient death (hazard ratio 0·62 [95% CI 0·57-0·68]; p<0·0001), congestive heart failure (0·70 [0·58-0·85]; p=0·0002), atrial fibrillation (0·63 [0·52-0·76]; p<0·0001), coronary artery disease (0·71 [0·59-0·85]; p=0·0002), chronic pulmonary disease (0·68 [0·54-0·86]; p=0·0011), acute respiratory distress syndrome (0·71 [0·58-0·86]; p=0·0007), interstitial lung disease (0·17 [0·04-0·75]; p=0·020), and end-stage renal disease (0·37 [0·18-0·74]; p=0·0049). There was no evidence indicating difference between the groups in deep vein thrombosis, seizure, anxiety, post-traumatic stress disorder, acute kidney injury, and pancreatitis. INTERPRETATION: This study showed extended benefits of nirmatrelvir-ritonavir for reducing the risk of post-acute inpatient death as well as cardiovascular and respiratory complications among patients admitted to hospital with COVID-19. Further research is essential to uncover the underlying mechanisms responsible for these observed negative associations and to devise effective strategies for preventing the onset of post-acute sequelae. FUNDING: Health and Medical Research Fund, Research Grants Council theme-based research schemes, and Research Grants Council Collaborative Research Fund.

Cost of Hospitalization Associated with Inpatient Goals-of-Care Program Implementation at a Comprehensive Cancer Center: A Propensity Score Analysis.

The impact of goals-of-care programs on acute hospitalization costs is unclear. We compared the hospitalization cost in an 8-month period before implementation of a multimodal interdisciplinary goals-of-care program (1 May 2019 to 31 December 2019) to an 8-month period after program implementation (1 May 2020 to 31 December 2020). Propensity score weighting was used to adjust for differences in potential covariates. The primary outcome was total direct cost during the hospital stay for each index hospitalization. This analysis included 6977 patients in 2019 and 5964 patients in 2020. The total direct cost decreased by 3% in 2020 but was not statistically significant (ratio 0.97, 95% CI 0.92, 1.03). Under individual categories, there was a significant decrease in medical oncology (ratio 0.58, 95% CI 0.50, 0.68) and pharmacy costs (ratio 0.86, 95% CI 0.79, 0.96), and an increase in room and board (ratio 1.06, 95% CI 1.01, 1.10). In subgroup analysis, ICU patients had a significant reduction in total direct cost after program implementation (ratio 0.83, 95% CI 0.72, 0.94). After accounting for the length of ICU admission, we found that the total direct cost per hospital day was no longer different between 2019 and 2020 (ratio 0.986, 95% CI 0.92, 1.05), suggesting that shorter ICU admissions likely explained much of the observed cost savings. This study provides real-world data on how "in-the-moment" GOC conversations may contribute to reduced hospitalization costs among ICU patients.

Avian 'Bird' Flu - undue media panic or genuine concern for pandemic potential requiring global preparedness action?

epidemics, avian influenza, H5N1, highly pathogenic avian influenza, HPAI.

Telehealth Preferences Among Patients With Advanced Cancer in the Post COVID-19 Vaccine Era.

BACKGROUND: Few studies have examined patient preferences for telehealth in palliative care after the availability of COVID-19 vaccines. We examined patient preferences for video versus in-person visits and factors contributing to preferences in the postvaccine era. METHODS: This is a cross-sectional survey of patients who were seen at our palliative care clinic between April 2021 and March 2022. Patients were surveyed directly their preference for either video or in-person visits for outpatient palliative care (primary outcome). We also surveyed preferences including convenience, cost, wait time, and perceptions of COVID-19 safety regarding their palliative virtual-video visit. We examined clinical factors associated with preferences with multivariate logistic regression. RESULTS: About 200 patients completed the survey. 132 (67%, 95% confidence interval [CI]: 60%, 74%) preferred virtual-video, while 16 (8%) preferred in-person visits during the COVID-19 pandemic. About 120 (61%, 95%CI: 54%, 68%) preferred virtual-video after the pandemic. Patients perceived virtual-video favorably regarding travel and related costs (179 [91%]), convenience (175 [88%]), and wait time (136 [69%]). Multivariable analysis showed concerns for catching COVID-19 from healthcare providers (odds ratio [OR]: 4.20; 95%CI: 1.24-14.25; P = 0.02) and feeling comfortable with computers or mobile devices (OR: 4.59; 95%CI: 1.02, 20.60; P = 0.047) were significantly associated with preferring virtual-video. Patients who were of Hispanic or Latino ethnicity (OR: 0.25; 95%CI: 0.09, 0.71) and had increased dypsnea (OR: 0.74; 95%CI: 0.59, 0.93) were less likely to prefer video over in-person. CONCLUSION: Patients expressed strong preference for video over in-person visits in the outpatient palliative care setting.

Cross-neutralizing antibody against emerging Omicron subvariants of SARS-CoV-2 in infection-naïve individuals with homologous BNT162b2 or BNT162b2(WT + BA.4/5) bivalent booster vaccination.

Since the emergence of SARS-CoV-2, different variants and subvariants successively emerged to dominate global virus circulation as a result of immune evasion, replication fitness or both. COVID-19 vaccines continue to be updated in response to the emergence of antigenically divergent viruses, the first being the bivalent RNA vaccines that encodes for both the Wuhan-like and Omicron BA.5 subvariant spike proteins. Repeated infections and vaccine breakthrough infections have led to complex immune landscapes in populations making it increasingly difficult to assess the intrinsic neutralizing antibody responses elicited by the vaccines. Hong Kong's intensive COVID-19 containment policy through 2020-2021 permitted us to identify sera from a small number of infection-naïve individuals who received 3 doses of the RNA BNT162b2 vaccine encoding the Wuhan-like spike (WT) and were boosted with a fourth dose of the WT vaccine or the bivalent WT and BA.4/5 spike (WT + BA.4/5). While neutralizing antibody to wild-type virus was comparable in both vaccine groups, BNT162b2 (WT + BA.4/BA.5) bivalent vaccine elicited significantly higher plaque neutralizing antibodies to Omicron subvariants BA.5, XBB.1.5, XBB.1.16, XBB.1.9.1, XBB.2.3.2, EG.5.1, HK.3, BA.2.86 and JN.1, compared to BNT162b2 monovalent vaccine. The single amino acid substitution that differentiates the spike of JN.1 from BA.2.86 resulted in a profound antigenic change.

Perspectives on development and advancement of new tuberculosis vaccines.

Tuberculosis (TB) remains a leading cause of death worldwide and is estimated to have caused 1.3 million deaths worldwide in 2022. Approximately one quarter of the world's population are infected with Mycobacterium tuberculosis, of whom up to 10% will progress to developing active TB disease. Achieving the World Health Organization End TB Strategy targets of a 95% reduction in TB mortality and a 90% reduction in TB incidence worldwide by 2035 remains a daunting task. The continuing spread of multidrug-resistant TB adds another obstacle to achieving global TB control. Larger funding pledges coupled with technological advances have recently enabled the enhancement of TB vaccine development efforts. These are yielding a pipeline of over 17 products currently in different stages of clinical trials. Emerging promising phase I and II trial results and advancement to phase III trials have necessitated "vaccine preparedness" in parallel so that a smooth transition from any positive clinical trial result to phase IV evaluation and implementation into policy and practice can follow. Promotion of a human rights-based approach, which recognizes and upholds the fundamental rights of all affected by the disease, is essential to ensure universal access to quality TB vaccines, regardless of their background or personal circumstances.

Quantitative and qualitative subgenomic RNA profiles of SARS-CoV-2 in respiratory samples: A comparison between Omicron BA.2 and non-VOC-D614G.

The SARS-CoV-2 Omicron variants are notorious for their transmissibility, but little is known about their subgenomic RNA (sgRNA) expression. This study applied RNA-seq to delineate the quantitative and qualitative profiles of canonical sgRNA of 118 respiratory samples collected from patients infected with Omicron BA.2 and compared with 338 patients infected with non-variant of concern (non-VOC)-D614G. A unique characteristic profile depicted by the relative abundance of 9 canonical sgRNAs was reproduced by both BA.2 and non-VOC-D614G regardless of host gender, age and presence of pneumonia. Remarkably, such profile was lost in samples with low viral load, suggesting a potential application of sgRNA pattern to indicate viral activity of individual patient at a specific time point. A characteristic qualitative profile of canonical sgRNAs was also reproduced by both BA.2 and non-VOC-D614G. The presence of a full set of canonical sgRNAs carried a coherent correlation with crude viral load (AUC â€‹= â€‹0.91, 95% CI 0.88-0.94), and sgRNA ORF7b was identified to be the best surrogate marker allowing feasible routine application in characterizing the infection status of individual patient. Further potentials in using sgRNA as a target for vaccine and antiviral development are worth pursuing.

Chatbot Performance in Defining and Differentiating Palliative Care, Supportive Care, Hospice Care.

CONTEXT: Artificial intelligence (AI) chatbot platforms are increasingly used by patients as sources of information. However, there is limited data on the performance of these platforms, especially regarding palliative care terms. OBJECTIVES: We evaluated the accuracy, comprehensiveness, reliability, and readability of three AI platforms in defining and differentiating "palliative care," "supportive care," and "hospice care." METHODS: We asked ChatGPT, Microsoft Bing Chat, Google Bard to define and differentiate "palliative care," "supportive care," and "hospice care" and provide three references. Outputs were randomized and assessed by six blinded palliative care physicians using 0-10 scales (10 = best) for accuracy, comprehensiveness, and reliability. Readability was assessed using Flesch Kincaid Grade Level and Flesch Reading Ease scores. RESULTS: The mean (SD) accuracy scores for ChatGPT, Bard, and Bing Chat were 9.1 (1.3), 8.7 (1.5), and 8.2 (1.7), respectively; for comprehensiveness, the scores for the three platforms were 8.7 (1.5), 8.1 (1.9), and 5.6 (2.0), respectively; for reliability, the scores were 6.3 (2.5), 3.2 (3.1), and 7.1 (2.4), respectively. Despite generally high accuracy, we identified some major errors (e.g., Bard stated that supportive care had "the goal of prolonging life or even achieving a cure"). We found several major omissions, particularly with Bing Chat (e.g., no mention of interdisciplinary teams in palliative care or hospice care). References were often unreliable. Readability scores did not meet recommended levels for patient educational materials. CONCLUSION: We identified important concerns regarding the accuracy, comprehensiveness, reliability, and readability of outputs from AI platforms. Further research is needed to improve their performance.

Clinical characteristics and healthcare resource utilization in patients with chronic obstructive pulmonary disease in Hong Kong.

OBJECTIVES: Chronic obstructive pulmonary disease (COPD) is a significant cause of mortality, with its prevalence projected to rise in Asia. The primary objective of this study was to describe clinical characteristics, maintenance treatment, and healthcare resource utilization (HCRU) among patients with COPD in Hong Kong. Secondary objectives were to assess patient demographics and clinical characteristics by eosinophil (EOS) levels, and compare the demographics, clinical characteristics, and treatment patterns of patients on multiple-inhaler triple therapy (MITT). METHODS: This study analyzed a cohort of patients with COPD who had entered a previously initiated prospective cohort study involving patients with COPD and/or asthma at the Prince of Wales Hospital between 2017 and 2019. RESULTS: Patients with COPD were enrolled (N = 220, mean age 74.3 years, 97 % male). Twelve months prior to baseline assessment, 66 % of patients were on MITT, 17 % on long-acting muscarinic antagonists (LAMAs)/long-acting beta-agonists (LABAs), and 7 % on inhaled corticosteroids (ICS)/LABA. Compared with ICS/LABA or LAMA/LABA, more patients on MITT experienced ≥1 exacerbation (26.7 %, 10.5 %, 39.7 %, respectively). Patients on MITT also had a higher mean (SD) COPD Assessment Test score (9.4 [5.9]) and modified Medical Research Council Dyspnea Scale score (1.7 [0.7]) and incurred the most COPD-related and total HCRU costs. Compared with patients with EOS ≤300 cells/µL, those with EOS >300 cells/µL had a higher number of exacerbations. CONCLUSIONS: Patients with COPD in Hong Kong treated with MITT presented more severe disease profiles and incurred higher costs. These data can be used for decision making in patients with moderate-to-severe COPD in Hong Kong.

Inferring Incidence of Unreported SARS-CoV-2 Infections Using Seroprevalence of Open Reading Frame 8 Antigen, Hong Kong.

We tested seroprevalence of open reading frame 8 antigens to infer the number of unrecognized SARS-CoV-2 Omicron infections in Hong Kong during 2022. We estimate 33.6% of the population was infected, 72.1% asymptomatically. Surveillance and control activities during large-scale outbreaks should account for potentially substantial undercounts.

Are Surprise Questions and Probabilistic Questions by Nurses Useful in Home Palliative Care? A Prospective Study.

Background: Surprise questions (SQs) are used as screening tools in palliative care. Probabilistic questions (PQs) are more accurate than temporal predictions. However, no study has examined the usefulness of SQs and PQs assessed by nurses. Objectives: To examine the accuracy of nurses' SQ and PQ assessments in patients with advanced cancer receiving home palliative care. Design: A prospective single-center cohort study. Setting/Subjects: Adult patients with advanced cancer who received palliative care at home in South Korea between 2019 and 2020. Measurements: Palliative care specialized nurses were asked the SQ, "Would you be surprised if the patient died in a specific timeframe?" and PQ, "What is the probability that this patient will be alive (0 to 100%) within a specific timeframe?" at the 1-, 2-, 4-, and 6-week timeframes at enrollment. We calculated the sensitivities and specificities of the SQs and PQs. Results: 81 patients were recruited with 47 days of median survival. The sensitivity, specificity, and overall accuracy (OA) of the 1-week SQ were 50.0, 93.2, and 88.9%, respectively. The accuracies for the 1-week PQ were 12.5, 100.0, and 91.3%, respectively. The 6-week SQ showed sensitivity, specificity, and OA of 84.6, 42.9, and 62.9%, respectively; the accuracies for the 6-week PQ were 59.0, 66.7, and 63.0%, respectively.Conclusion: The SQ and PQ showed acceptable accuracy in home palliative care patients. Interestingly, PQ showed higher specificity than SQ at all timeframes. The SQ and PQ assessed by nurses may be useful in providing additional prognostic information for home palliative care.

Improved Symptom Change Enhances Quality of Dying in Patients With Advanced Cancer: An East Asian Cross-Cultural Study.

BACKGROUND: Symptom burdens tend to increase for patients with cancer and their families over the disease trajectory. There is still a lack of evidence on the associations between symptom changes and the quality of dying and death. In this context, this research investigated how symptom changes influence the quality of dying and death. METHODS: This international prospective cohort study (the East Asian Collaborative Cross-Cultural Study to Elucidate the Dying Process (EASED), 2017-2019) included 22, 11, and 4 palliative care units across Japan, South Korea, and Taiwan. Eligible participants were adults (Japan and Korea, ≥18 years; Taiwan, ≥20 years) with locally advanced or metastatic cancer. Physical and psychological symptoms were assessed by physicians upon admission and within 3 days before death. Death quality was assessed using the Good Death Scale (GDS), developed in Taiwan. Univariate and multivariate regression analyses were used to identify correlations between symptom severity changes and GDS scores. RESULTS: Among 998 patients (542 [54.3%] men and 456 [45.7%] women; mean [SD] age = 70.1 [± 12.5] years), persistent dyspnea was associated with lower GDS scores when compared to stable dyspnea (ß = -0.427, 95% CI = -0.783 to -0.071). Worsened (-1.381, -1.932 to -0.831) and persistent (-1.680, -2.701 to -0.659) delirium were also significantly associated with lower GDS scores. CONCLUSIONS: Better quality of dying and death was associated with improved symptom control, especially for dyspnea and delirium. Integrating an outcome measurement for the quality of dying and death is important in the management of symptoms across the disease trajectory in a goal-concordant manner.

Impact of Dosing and Duration of Dexamethasone on Serious Corticosteroid-Related Adverse Events.

CONTEXT: Corticosteroids are commonly prescribed in oncology, but few studies have examined its adverse events (AEs) compared to placebo control. OBJECTIVES: Using data from a double-blind, placebo-controlled randomized trial, we evaluated the association between the dose and duration of dexamethasone and serious AEs. METHODS: This is a pre-planned secondary analysis of the Alleviating Breathlessness in Cancer Patients with Dexamethasone (ABCD) trial in which patients were randomized to dexamethasone 8 mg BID x1 week, then 4 mg BID x1 week or placebo, followed by an optional open-label phase with 4 mg BID x1 week, then 2 mg BID x1 week. The primary outcome was Grade 3+ AEs (CTCAE v4.03). We evaluated the association between AEs and dexamethasone exposure using multivariable logistic regression. RESULTS: Among 119 cancer patients, 32 received intervention followed by open label (mean exposure 243 mg over 27 days), 47 received intervention with no open label, 20 received placebo followed by open label, and 20 received no dexamethasone. The most common AEs included insomnia (31%), dyspepsia (21%), neuropsychiatric symptoms (18%), and infections (17%). Overall, 38 (32%) had Grade 3+ AEs and 27 (23%) were hospitalized. Patients with the greatest exposure to dexamethasone experienced more Grade 3+ AEs compared to those with no exposure (65% vs. 15%); odds ratio of 15.1 (95% CI 1.4-160.8, P = 0.01). CONCLUSION: Greater dexamethasone exposure, even at moderate doses, was associated with more serious AEs. Prescribers should cautiously weigh the risks and benefits of dexamethasone use, especially when considering for palliation of symptoms.

Coping Strategies and Associated Symptom Burden Among Patients With Advanced Cancer.

BACKGROUND: Few studies examine how patients with advanced cancer cope with stress. The objective of our study was to evaluate coping strategies adopted by patients with cancer and their relationship with symptom burden. METHODS: A secondary data analysis of a prospective cross-sectional survey of patients with cancer and tobacco use was conducted, which examined demographics, symptom burden (Edmonton Symptom Assessment System), and coping strategies (the Brief COPE Questionnaire). Demographic characteristics were summarized by standard summary statistics; we also examined associations between patient characteristics and coping strategies using t-test, rank-sum test, chi-squared test, or Fisher's exact test depending on the distribution of data. RESULTS: Among 399 patients, the majority were female (60%), Caucasian (70%), the mean age was 56.5 (±12.0) years, and the most common malignancies were gastrointestinal (21%) and breast (19%). Patients with cancer adopted multiple adaptive coping strategies, most frequently acceptance (86.7%) and emotional support (79.9%), with humor (18.5%) being the least. Common maladaptive strategies included venting (14.5%) and self-distraction (36.6%), while substance use (1.0%) was infrequently reported. Of the adaptive strategies, female gender was significantly associated with higher engagement with emotional and instrumental support, positive reframing, religious coping, and acceptance (P < .05 for all). College educated patients reported significantly higher implementation of humor, planning, and acceptance. Maladaptive coping strategies such as denial were associated with increased pain and depression, while patients adopting emotional-focused strategies rated decreased emotional distress. CONCLUSIONS: The majority of patients with advanced cancer reported adopting multiple, adaptive coping strategies, and a minority utilized maladaptive or avoidant strategies, rarely substance use, and may need additional psychological support.

Serological assays for differentiating natural COVID-19 infection from vaccine induced immunity.

BACKGROUND: Natural SARS-CoV-2 infection may elicit antibodies to a range of viral proteins including non-structural protein ORF8. RNA, adenovirus vectored and sub-unit vaccines expressing SARS-CoV-2 spike would be only expected to elicit S-antibodies and antibodies to distinct domains of nucleocapsid (N) protein may reliably differentiate infection from vaccine-elicited antibody. However, inactivated whole virus vaccines may potentially elicit antibody to wider range of viral proteins, including N protein. We hypothesized that antibody to ORF8 protein will discriminate natural infection from vaccination irrespective of vaccine type. METHODS: We optimized and validated the anti-ORF8 and anti-N C-terminal domain (NCTD) ELISA assays using sera from pre-pandemic, RT-PCR confirmed natural infection sera and BNT162b2 (BNT) or CoronaVac vaccinees. We then applied these optimized assays to a cohort of blood donor sera collected in April-July 2022 with known vaccination and self-reported infection status. RESULTS: We optimized cut-off values for the anti-ORF8 and anti-N-CTD IgG ELISA assays using receiver-operating-characteristic (ROC) curves. The sensitivity of the anti-ORF8 and anti-N-CTD ELISA for detecting past infection was 83.2% and 99.3%, respectively. Specificity of anti-ORF8 ELISA was 96.8 % vs. the pre-pandemic cohort or 93% considering the pre-pandemic and vaccine cohorts together. The anti-N-CTD ELISA specificity of 98.9% in the pre-pandemic cohort, 93% in BNT vaccinated and only 4 % in CoronaVac vaccinated cohorts. Anti-N-CTD antibody was longer-lived than anti-ORF8 antibody after natural infection. CONCLUSIONS: Anti-N-CTD antibody assays provide good discrimination between natural infection and vaccination in BNT162b2 vaccinated individuals. Anti-ORF8 antibody can help discriminate infection from vaccination in either type of vaccine and help estimate infection attack rates (IAR) in communities.