Durability and breadth of neutralisation following multiple antigen exposures to SARS-CoV-2 infection and/or COVID-19 vaccination.

BACKGROUND: Given the importance of vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the prevention of severe coronavirus disease 2019 (COVID-19), detailed long-term analyses of neutralising antibody responses are required to inform immunisation strategies. METHODS: In this study, longitudinal neutralising antibody titres to an ancestral SARS-CoV-2 isolate and cross-neutralisation to delta and omicron isolates were analysed in individuals previously infected with SARS-CoV-2, vaccinated against COVID-19, or a complex mix thereof with up to two years of follow-up. FINDINGS: Both infection-induced and vaccine-induced neutralising responses against SARS-CoV-2 appeared to follow similar decay patterns. Following vaccination in previously infected individuals, neutralising antibody responses were more durable than prior to vaccination. Further, this study shows that vaccination after infection, as well as booster vaccination, increases the cross-neutralising potential to both delta and omicron SARS-CoV-2 variants. INTERPRETATION: Taken together, these results suggest that neither type of antigen exposure is superior for neutralising antibody durability. However, these results support vaccination to increase the durability and cross-neutralisation potential of neutralising responses, thereby enhancing protection against severe COVID-19. FUNDING: This work was supported by grants from The Capital Region of Denmark's Research Foundation, the Novo Nordisk Foundation, the Independent Research Fund Denmark, the Candys Foundation, and the Danish Agency for Science and Higher Education.

SARS-CoV-2 spike mRNA vaccine sequences circulate in blood up to 28 days after COVID-19 vaccination.

In Denmark, vaccination against Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) has been with the Pfizer-BioNTech (BTN162b2) or the Moderna (mRNA-1273) mRNA vaccines. Patients with chronic hepatitis C virus (HCV) infection followed in our clinic received mRNA vaccinations according to the Danish roll-out vaccination plan. To monitor HCV infection, RNA was extracted from patient plasma and RNA sequencing was performed on the Illumina platform. In 10 of 108 HCV patient samples, full-length or traces of SARS-CoV-2 spike mRNA vaccine sequences were found in blood up to 28 days after COVID-19 vaccination. Detection of mRNA vaccine sequences in blood after vaccination adds important knowledge regarding this technology and should lead to further research into the design of lipid-nanoparticles and the half-life of these and mRNA vaccines in humans.

Psychological Distress among Hospitalized COVID-19 Patients in Denmark during the First 12 Months of the Pandemic.

This study aimed to investigate psychological distress among patients hospitalized with a COVID-19 diagnosis in Denmark during the first 12 months of the pandemic and to assess changes in psychological distress in the three months following discharge. A single-center prospective observational survey study among patients hospitalized with a COVID-19 diagnosis between May 2020 and May 2021 was conducted. Participants completed a survey at three time points: at admission, and 1 and 3 months after discharge. Psychological distress was assessed by validated scales measuring symptoms related to depression, anxiety, stress, insomnia, post-traumatic stress disorder (PTSD), and health-related quality of life (HRQoL). In total, 95 patients were included. At admission, the proportion of patients with symptoms of depression was 43%, symptoms of anxiety 32%, moderate/high level of stress 39%, insomnia 52%, and probable/positive PTSD 19%. The burden of symptoms related to depression and anxiety decreased significantly over time, while there was no significant change over time in stress, insomnia, or PTSD. Suboptimal levels of physical and mental HRQoL were detected at admission but improved over time. Patients hospitalized due to COVID-19 during the first year of the pandemic experienced considerable levels of psychological distress at admission, with some improvements within 3 months after discharge.

Cross-reactive immunity against SARS-CoV-2 N protein in Central and West Africa precedes the COVID-19 pandemic.

Early predictions forecasted large numbers of severe acute respiratory syndrome coronavirus (SARS-CoV-2) cases and associated deaths in Africa. To date, Africa has been relatively spared. Various hypotheses were postulated to explain the lower than anticipated impact on public health in Africa. However, the contribution of pre-existing immunity is yet to be investigated. In this study, the presence of antibodies against SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in pre-pandemic samples from Africa, Europe, South and North America was examined by ELISA. The protective efficacy of N specific antibodies isolated from Central African donors was tested by in vitro neutralization and in a mouse model of SARS-CoV-2 infection. Antibodies against SARS-CoV-2 S and N proteins were rare in all populations except in Gabon and Senegal where N specific antibodies were prevalent. However, these antibodies failed to neutralize the virus either in vitro or in vivo. Overall, this study indicates that cross-reactive immunity against SARS-CoV-2 N protein was present in Africa prior to the pandemic. However, this pre-existing humoral immunity does not impact viral fitness in rodents suggesting that other human immune defense mechanisms could be involved. In Africa, seroprevalence studies using the N protein are over-estimating SARS-CoV-2 circulation.

Analysis of Neutralization Titers against SARS-CoV-2 in Health-Care Workers Vaccinated with Prime-Boost mRNA–mRNA or Vector–mRNA COVID-19 Vaccines

With increasing numbers of vaccine-breakthrough infections worldwide, assessing the immunogenicity of vaccinated health-care workers that are frequently exposed to SARS-CoV-2-infected individuals is important. In this study, neutralization titers against SARS-CoV-2 were assessed one month after completed prime-boost vaccine regimens in health-care workers vaccinated with either mRNA–mRNA (Comirnaty®, BioNTech-Pfzier, Mainz, Germany/New York, NY, USA, n = 98) or vector-based (Vaxzevria®, Oxford-AstraZeneca, Cambridge, UK) followed by mRNA-based (Comirnaty® or Spikevax®, Moderna, Cambridge, MA, USA) vaccines (n = 16). Vaccine-induced neutralization titers were compared to time-matched, unvaccinated individuals that were infected with SARS-CoV-2 and presented with mild symptoms (n = 38). Significantly higher neutralizing titers were found in both the mRNA–mRNA (ID50: 2525, IQR: 1667–4313) and vector–mRNA (ID50: 4978, IQR: 3364–7508) prime-boost vaccine regimens when compared to SARS-CoV-2 infection (ID50: 401, IQR: 271–792) (p < 0.0001). However, infection with SARS-CoV-2 induced higher titers when compared to a single dose of Vaxzevria® (p = 0.0072). Between mRNA–mRNA and vector–mRNA prime-boost regimens, the vector–mRNA vaccine regimen induced higher neutralization titers (p = 0.0054). Demographically, both age and time between vaccination doses were associated with vaccine-induced neutralization titers (p = 0.02 and p = 0.03, respectively). This warrants further investigation into the optimal time to administer booster vaccination for optimized induction of neutralizing responses. Although anecdotal (n = 3), those with exposure to SARS-CoV-2, either before or after vaccination, demonstrated superior neutralizing titers, which is suggestive of further boosting through viral exposure.

Effect of PEP flute self-care versus usual care in early covid-19: non-drug, open label, randomised controlled trial in a Danish community setting.

OBJECTIVE: To determine whether positive expiratory pressure (PEP) by PEP flute self-care is effective in reducing respiratory symptoms among community dwelling adults with SARS-CoV-2 infection and early stage covid-19. DESIGN: Non-drug, open label, randomised controlled trial. SETTING: Capital Region and Region Zealand in Denmark from 6 October 2020 to 26 February 2021. PARTICIPANTS: Community dwelling adults, able to perform self-care, with a new SARS-CoV-2 infection (verified by reverse transcription polymerase chain reaction tests) and symptoms of covid-19. INTERVENTION: Participants were randomised to use PEP flute self-care in addition to usual care or have usual care only. Randomisation was based on permuted random blocks in a 1:1 ratio, stratified for sex and age (<60 or ≥60 years). The PEP self-care group was instructed to use a PEP flute three times per day during the 30 day intervention. MAIN OUTCOME MEASURES: Primary outcome was a change in symptom severity from baseline to day 30, as assessed by the self-reported COPD (chronic obstructive pulmonary disease) assessment test (CAT), which was adjusted for baseline values and stratification factors. Participants completed the CAT test questionnaire every day online. Secondary outcomes were self-reported urgent care visits due to covid-19, number of covid-19 related symptoms, and change in self-rated health, all within 30-days' follow-up. RESULTS: 378 participants were assigned to the PEP flute self-care intervention (n=190) or usual care only (n=188). In the PEP self-care group, the median number of days with PEP flute use was 21 days (interquartile range 13-25). For the intention-to-treat population, a group difference was observed in changes from baseline in CAT scores of -1.2 points (95% confidence interval -2.1 to -0.2; P=0.017) in favour of the PEP flute self-care group. At day 30, the PEP flute self-care group also reported less chest tightness, less dyspnoea, more vigour, and higher level of daily activities, but these differences were small, and no consistent effects were seen on the secondary outcomes. No serious adverse events were reported. CONCLUSIONS: In community dwelling adults with early covid-19, PEP flute self-care had a significant, yet marginal and uncertain clinical effect on respiratory symptom severity, as measured by CAT scores. TRIAL REGISTRATION: ClinicalTrials.gov NCT04530435.

Overcoming Culture Restriction for SARS-CoV-2 in Human Cells Facilitates the Screening of Compounds Inhibiting Viral Replication.

Efforts to mitigate the coronavirus disease 2019 (COVID-19) pandemic include the screening of existing antiviral molecules that could be repurposed to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Although SARS-CoV-2 replicates and propagates efficiently in African green monkey kidney (Vero) cells, antivirals such as nucleos(t)ide analogs (NUCs) often show decreased activity in these cells due to inefficient metabolization. SARS-CoV-2 exhibits low viability in human cells in culture. Here, serial passages of a SARS-CoV-2 isolate (original-SARS2) in the human hepatoma cell clone Huh7.5 led to the selection of a variant (adapted-SARS2) with significantly improved infectivity in human liver (Huh7 and Huh7.5) and lung cancer (unmodified Calu-1 and A549) cells. The adapted virus exhibited mutations in the spike protein, including a 9-amino-acid deletion and 3 amino acid changes (E484D, P812R, and Q954H). E484D also emerged in Vero E6-cultured viruses that became viable in A549 cells. Original and adapted viruses were susceptible to scavenger receptor class B type 1 (SR-B1) receptor blocking, and adapted-SARS2 exhibited significantly less dependence on ACE2. Both variants were similarly neutralized by COVID-19 convalescent-phase plasma, but adapted-SARS2 exhibited increased susceptibility to exogenous type I interferon. Remdesivir inhibited original- and adapted-SARS2 similarly, demonstrating the utility of the system for the screening of NUCs. Among the tested NUCs, only remdesivir, molnupiravir, and, to a limited extent, galidesivir showed antiviral effects across human cell lines, whereas sofosbuvir, ribavirin, and favipiravir had no apparent activity. Analogously to the emergence of spike mutations in vivo, the spike protein is under intense adaptive selection pressure in cell culture. Our results indicate that the emergence of spike mutations will most likely not affect the activity of remdesivir.

Neutralisation titres against SARS-CoV-2 are sustained 6 months after onset of symptoms in individuals with mild COVID-19.

BACKGROUND: Given the importance of neutralising antibodies in protection against SARS-CoV-2 infection, it is critical to assess neutralisation persistence long-term following recovery. This study investigated neutralisation titres against SARS-CoV-2 up to 6 months post-symptom onset in individuals with mild COVID-19. METHODS: Plasma neutralisation titres in convalescent COVID-19 individuals were determined at baseline and 6 months post-symptom onset using a cell culture infectious SARS-CoV-2 assay. Total SARS-CoV-2 spike-specific IgG and IgA binding was measured using a lectin capture ELISA and compared between timepoints and correlated to neutralising titres. FINDINGS: All 48 convalescent COVID-19 individuals were found to have detectable SARS-CoV-2 50% inhibitory dilution neutralisation titres (ID50) at baseline and 6 months post-symptom onset with mean ID50 of 1/943 and 1/411, respectively. SARS-CoV-2 neutralisation titres peaked within 1-2 months post-symptom onset. However, 50% of individuals showed comparable ID50 at baseline and 6 months post-symptom onset. Both SARS-CoV-2 spike-specific IgG and IgA levels correlated well with neutralising titres. IgG binding was found to be sustained up to 6 months post-symptom onset, whereas IgA levels declined. INTERPRETATION: This study demonstrates durability of SARS-CoV-2 spike-specific IgG and neutralisation responses following recovery from mild COVID-19. Thus, all subjects included in this study might potentially have protective levels of neutralising antibodies 6 months post-symptom onset. This study also demonstrates a relationship between spike-specific IgA and neutralisation decline, with implications for long-term protection against SARS-CoV-2 infection. FUNDING: Novo Nordisk Foundation, Independent Research Fund Denmark and Danish Agency for Science and Higher Education.

In vitro Characterization of Fitness and Convalescent Antibody Neutralization of SARS-CoV-2 Cluster 5 Variant Emerging in Mink at Danish Farms.

In addition to humans, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transmit to animals that include hamsters, cats, dogs, mink, ferrets, tigers, lions, cynomolgus macaques, rhesus macaques, and treeshrew. Among these, mink are particularly susceptible. Indeed, 10 countries in Europe and North America reported SARS-CoV-2 infection among mink on fur farms. In Denmark, SARS-CoV-2 spread rapidly among mink farms and spilled-over back into humans, acquiring mutations/deletions with unknown consequences for virulence and antigenicity. Here we describe a mink-associated SARS-CoV-2 variant (Cluster 5) characterized by 11 amino acid substitutions and four amino acid deletions relative to Wuhan-Hu-1. Temporal virus titration, together with genomic and subgenomic viral RNA quantitation, demonstrated a modest in vitro fitness attenuation of the Cluster 5 virus in the Vero-E6 cell line. Potential alterations in antigenicity conferred by amino acid changes in the spike protein that include three substitutions (Y453F, I692V, and M1229I) and a loss of two amino acid residues 69 and 70 (ΔH69/V70), were evaluated in a virus microneutralization assay. Compared to a reference strain, the Cluster 5 variant showed reduced neutralization in a proportion of convalescent human COVID-19 samples. The findings underscore the need for active surveillance SARS-CoV-2 infection and virus evolution in susceptible animal hosts.

PEP-CoV protocol: a PEP flute-self-care randomised controlled trial to prevent respiratory deterioration and hospitalisation in early COVID-19.

INTRODUCTION: Infection with SARS-CoV-2 may progress to severe pulmonary disease, COVID-19. Currently, patients admitted to hospital because of COVID-19 have better prognosis than during the first period of the pandemic due to improved treatment. However, the overall societal susceptibility of being infected makes it pivotal to prevent severe courses of disease to avoid high mortality rates and collapse of the healthcare systems. Positive expiratory pressure (PEP) self-care is used in chronic pulmonary disease and has been shown to prevent pneumonia in a high-risk cohort of patients with leukaemia. PEP flute self-care to prevent respiratory deterioration and hospitalisation in early COVID-19: a randomised trial (The PEP-CoV trial) examines the effectiveness on respiratory symptoms and need of hospital admission by regular PEP flute use among non-hospitalised individuals with confirmed SARS-CoV-2 infection and COVID-19 symptoms. METHODS AND ANALYSIS: In this randomised controlled trial, we hypothesise that daily PEP flute usage as add-on to usual care is superior to usual care as regards symptom severity measured by the COPD Assessment Test (CAT) at 30-day follow-up (primary outcome) and hospital admission through register data (secondary outcome). We expect to recruit 400 individuals for the trial. Participants in the intervention group receive a kit of 2 PEP flutes and adequate resistances and access to instruction videos. A telephone hotline offers possible contact to a nurse. The eight-item CAT score measures cough, phlegm, chest tightness, dyspnoea, activities of daily living at home, feeling safe at home despite symptoms, sleep quality and vigour. The CAT score is measured daily in both intervention and control arms by surveys prompted through text messages. ETHICS AND DISSEMINATION: The study was registered prospectively at www.clinicaltrials.gov on 27 August 2020 (NCT04530435). Ethical approval was granted by the local health research ethics committee (Journal number: H-20035929) on 23 July 2020. Enrolment of participants began on 6 October 2020. Results will be published in scientific journals. TRIAL REGISTRATION NUMBER: NCT04530435; Pre-results.

The Copenhagen test and treat hepatitis C in a mobile clinic study: a protocol for an intervention study to enhance the HCV cascade of care for people who inject drugs (T'N'T HepC).

INTRODUCTION: Injecting drug use is the primary driver of hepatitis C virus (HCV) infection in Europe. Despite the need for more engagement with care, people who inject drugs (PWID) are hard to reach with HCV testing and treatment. We initiated a study to evaluate the efficacy for testing and linkage to care among PWID consulting peer-based testing at a mobile clinic in Copenhagen, Denmark. METHODS AND ANALYSIS: In this intervention study, we will recruit participants at a single community-based, peer-run mobile clinic. In a single visit, we will first offer participants a point-of-care HCV antibody test, and if they test positive, then they will receive an HCV RNA test. If they are HCV-RNA+, we will administer facilitated referrals to designated 'fast-track' clinics at a hospital or an addiction centre for treatment. The primary outcomes for this study are the number of tested and treated individuals. Secondary outcomes include individuals lost at each step in the care cascade. ETHICS AND DISSEMINATION: The results of this study could provide a model for targeting PWID for HCV testing and treatment in Demark and other settings, which could help achieve WHO HCV elimination targets. The Health Research Ethics Committee of Denmark and the Danish Data Protection Agency confirmed (December 2018/January 2019) that this study did not require their approval. Study findings will be disseminated through peer-reviewed publications, conference presentations and social media.