Impaired humoral immunity to BQ.1.1 in convalescent and vaccinated patients.

Determining SARS-CoV-2 immunity is critical to assess COVID-19 risk and the need for prevention and mitigation strategies. We measured SARS-CoV-2 Spike/Nucleocapsid seroprevalence and serum neutralizing activity against Wu01, BA.4/5 and BQ.1.1 in a convenience sample of 1,411 patients receiving medical treatment in the emergency departments of five university hospitals in North Rhine-Westphalia, Germany, in August/September 2022. 62% reported underlying medical conditions and 67.7% were vaccinated according to German COVID-19 vaccination recommendations (13.9% fully vaccinated, 54.3% one booster, 23.4% two boosters). We detected Spike-IgG in 95.6%, Nucleocapsid-IgG in 24.0%, and neutralization against Wu01, BA.4/5 and BQ.1.1 in 94.4%, 85.0%, and 73.8% of participants, respectively. Neutralization against BA.4/5 and BQ.1.1 was 5.6- and 23.4-fold lower compared to Wu01. Accuracy of S-IgG detection for determination of neutralizing activity against BQ.1.1 was reduced substantially. We explored previous vaccinations and infections as correlates of BQ.1.1 neutralization using multivariable and Bayesian network analyses. Given a rather moderate adherence to COVID-19 vaccination recommendations, this analysis highlights the need to improve vaccine-uptake to reduce the COVID-19 risk of immune evasive variants. The study was registered as clinical trial (DRKS00029414).

Immunological fingerprint in coronavirus disease-19 convalescents with and without post-COVID syndrome.

Background: Symptoms lasting longer than 12 weeks after severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection are called post-coronavirus disease (COVID) syndrome (PCS). The identification of new biomarkers that predict the occurrence or course of PCS in terms of a post-viral syndrome is vital. T-cell dysfunction, cytokine imbalance, and impaired autoimmunity have been reported in PCS. Nevertheless, there is still a lack of conclusive information on the underlying mechanisms due to, among other things, a lack of controlled study designs. Methods: Here, we conducted a prospective, controlled study to characterize the humoral and cellular immune response in unvaccinated patients with and without PCS following SARS-CoV-2 infection over 7 months and unexposed donors. Results: Patients with PCS showed as early as 6 weeks and 7 months after symptom onset significantly increased frequencies of SARS-CoV-2-specific CD4+ and CD8+ T-cells secreting IFNγ, TNF, and expressing CD40L, as well as plasmacytoid dendritic cells (pDC) with an activated phenotype. Remarkably, the immunosuppressive counterparts type 1 regulatory T-cells (TR1: CD49b/LAG-3+) and IL-4 were more abundant in PCS+. Conclusion: This work describes immunological alterations between inflammation and immunosuppression in COVID-19 convalescents with and without PCS, which may provide potential directions for future epidemiological investigations and targeted treatments.

Efficacy and safety of molnupiravir for the treatment of SARS-CoV-2 infection: a systematic review and meta-analysis.

BACKGROUND: The role of molnupiravir for coronavirus disease 2019 (COVID-19) treatment is unclear. METHODS: We conducted a systematic review until 1 November 2022 searching for randomized controlled trials (RCTs) involving COVID-19 patients comparing molnupiravir [±standard of care (SoC)] versus SoC and/or placebo. Data were pooled in random-effects meta-analyses. Certainty of evidence was assessed according to the Grading of Recommendations, Assessment, Development and Evaluations approach. RESULTS: Nine RCTs were identified, eight investigated outpatients (29 254 participants) and one inpatients (304 participants). Compared with placebo/SoC, molnupiravir does not reduce mortality [risk ratio (RR) 0.27, 95% CI 0.07-1.02, high-certainty evidence] and probably does not reduce the risk for 'hospitalization or death' (RR 0.81, 95% CI 0.55-1.20, moderate-certainty evidence) by Day 28 in COVID-19 outpatients. We are uncertain whether molnupiravir increases symptom resolution by Day 14 (RR 1.20, 95% CI 1.02-1.41, very-low-certainty evidence) but it may make no difference by Day 28 (RR 1.05, 95% CI 0.92-1.19, low-certainty evidence). In inpatients, molnupiravir may increase mortality by Day 28 compared with placebo (RR 3.78, 95% CI 0.50-28.82, low-certainty evidence). There is little to no difference in serious adverse and adverse events during the study period in COVID-19 inpatients/outpatients treated with molnupiravir compared with placebo/SoC (moderate- to high-certainty evidence). CONCLUSIONS: In a predominantly immunized population of COVID-19 outpatients, molnupiravir has no effect on mortality, probably none on 'hospitalization or death' and effects on symptom resolution are uncertain. Molnupiravir was safe during the study period in outpatients although a potential increase in inpatient mortality requires careful monitoring in ongoing clinical research. Our analysis does not support routine use of molnupiravir for COVID-19 treatment in immunocompetent individuals.

Early intervention with azelastine nasal spray may reduce viral load in SARS-CoV-2 infected patients.

With the changing epidemiology of COVID-19 and its impact on our daily lives, there is still an unmet need of COVID-19 therapies treating early infections to prevent progression. The current study was a randomized, parallel, double-blind, placebo-controlled trial. Ninety SARS-CoV-2 positive patients were randomized into 3 groups receiving placebo, 0.02% or 0.1% azelastine nasal spray for 11 days, during which viral loads were assessed by quantitative PCR. Investigators assessed patients' status throughout the trial including safety follow-ups (days 16 and 60). Symptoms were documented in patient diaries. Initial viral loads were log10 6.85 ± 1.31 (mean ± SD) copies/mL (ORF 1a/b gene). After treatment, virus load was reduced in all groups (p < 0.0001) but was greater in the 0.1% group compared to placebo (p = 0.007). In a subset of patients (initial Ct < 25) viral load was strongly reduced on day 4 in the 0.1% group compared to placebo (p = 0.005). Negative PCR results appeared earlier and more frequently in the azelastine treated groups: being 18.52% and 21.43% in the 0.1% and 0.02% groups, respectively, compared to 0% for placebo on day 8. Comparable numbers of adverse events occurred in all treatment groups with no safety concerns. The shown effects of azelastine nasal spray may thus be suggestive of azelastine's potential as an antiviral treatment.Trial registration: The study was registered in the German Clinical Trial Register (DRKS-ID: DRKS00024520; Date of Registration in DRKS: 12/02/2021). EudraCT number: 2020-005544-34.

Rapid selection of sotrovimab escape variants in SARS-CoV-2 Omicron infected immunocompromised patients.

BACKGROUND: Monoclonal antibodies (mAb) targeting SARS-CoV-2 are predominantly less effective against Omicron variants. Immunocompromised patients often experience prolonged viral shedding and are therefore at increased risk for viral escape mutations, when mAbs are used as monotherapy. METHODS: In an observational, prospective cohort, 57 patients infected with Omicron variants receiving sotrovimab alone or in combination with remdesivir were followed. The study endpoints were a decrease in SARS-CoV-2-RNA <106 copies/ml in nasopharyngeal swabs at day 21 and the emergence of resistance mutations at days 7, 14, and 21 after sotrovimab administration. All SARS-CoV-2 samples were analyzed by whole-genome sequencing, individual variants within the quasispecies were subsequently quantified and further characterized by a pseudovirus neutralization assay. RESULTS: 47/57 patients (82.5%) were infected with Omicron/BA.1 and 10/57 (17.5%) with Omicron/BA.2. The vast majority of patients (43/57, 75.4%) were immunodeficient, predominantly due to immunosuppression after organ transplantation or hematologic malignancies. 21 days after sotrovimab administration, 12/43 (27.9%) of immunodeficient patients had prolonged viral shedding compared to 1/14 (7.1%) immunocompetent patients (p = 0.011). Longitudinal sequencing revealed that 14/43 (32.6%) immunodeficient patients had in part Omicron-specific viral spike protein mutations (e.g., P337S and/or E340D/V) that substantially reduced susceptibility to sotrovimab in a pseudovirus neutralization assay. Combination therapy with remdesivir significantly reduced the selection of escape variants. CONCLUSIONS: Immunocompromised patients face a considerable risk of prolonged viral shedding and emergence of escape mutations after early therapy with sotrovimab. These findings underscore the importance of careful monitoring and the need to conduct dedicated clinical trials for this patient population.

Broadly neutralizing antibodies against HIV-1 and concepts for application.

Potent broadly neutralizing antibodies (bNAbs) targeting HIV-1 exhibit significant antiviral activity in humans. Recent advances have demonstrated that novel antibodies and bNAb combinations can effectively restrict the development of viral escape mutations. Moreover, passive immunization trials have provided proof-of-principle for bNAb-mediated prevention of infection with antibody-sensitive HIV-1 strains. In contrast, clinical studies investigating the activity of HIV-1 bNAbs on the latent reservoir failed to demonstrate substantial effects. Clinical adoption of HIV-1 bNAbs will require the development of more potent and broadly active antibodies as well as their implementation in optimized strategies to fully harness the capabilities of bNAbs. We review preclinical and clinical studies on HIV-1 bNAbs to highlight their potential and remaining limitations.

SARS-CoV-2 Omicron sublineages exhibit distinct antibody escape patterns.

SARS-CoV-2 neutralizing antibodies play a critical role in COVID-19 prevention and treatment but are challenged by viral evolution and the emergence of novel escape variants. Importantly, the recently identified Omicron sublineages BA.2.12.1 and BA.4/5 are rapidly becoming predominant in various countries. By determining polyclonal serum activity of 50 convalescent or vaccinated individuals against BA.1, BA.1.1, BA.2, BA.2.12.1, and BA.4/5, we reveal a further reduction in BA.4/5 susceptibility to vaccinee sera. Most notably, delineation of sensitivity to an extended 163-antibody panel demonstrates pronounced antigenic differences with distinct escape patterns among Omicron sublineages. Antigenic distance and/or higher resistance may therefore favor immune-escape-mediated BA.4/5 expansion after the first Omicron wave. Finally, while most clinical-stage monoclonal antibodies are inactive against Omicron sublineages, we identify promising antibodies with high pan-SARS-CoV-2 neutralizing potency. Our study provides a detailed understanding of Omicron-sublineage antibody escape that can inform on effective strategies against COVID-19.

Antibody-mediated neutralization of SARS-CoV-2.

Neutralizing antibodies can block infection, clear pathogens, and are essential to provide long-term immunity. Since the onset of the pandemic, SARS-CoV-2 neutralizing antibodies have been comprehensively investigated and critical information on their development, function, and potential use to prevent and treat COVID-19 have been revealed. With the emergence of SARS-CoV-2 immune escape variants, humoral immunity is being challenged, and a detailed understanding of neutralizing antibodies is essential to guide vaccine design strategies as well as antibody-mediated therapies. In this review, we summarize some of the key findings on SARS-CoV-2 neutralizing antibodies, with a focus on their clinical application.

No substantial preexisting B cell immunity against SARS-CoV-2 in healthy adults.

Preexisting immunity against SARS-CoV-2 may have critical implications for our understanding of COVID-19 susceptibility and severity. The presence and clinical relevance of a preexisting B cell immunity remain to be fully elucidated. Here, we provide a detailed analysis of the B cell immunity to SARS-CoV-2 in unexposed individuals. To this end, we extensively investigated SARS-CoV-2 humoral immunity in 150 adults sampled pre-pandemically. Comprehensive screening of donor plasma and purified IgG samples for binding and neutralization in various functional assays revealed no substantial activity against SARS-CoV-2 but broad reactivity to endemic betacoronaviruses. Moreover, we analyzed antibody sequences of 8,174 putatively SARS-CoV-2-reactive B cells at a single cell level and generated and tested 158 monoclonal antibodies. None of these antibodies displayed relevant binding or neutralizing activity against SARS-CoV-2. Taken together, our results show no evidence of competent preexisting antibody and B cell immunity against SARS-CoV-2 in unexposed adults.

Cross-Variant Neutralizing Serum Activity after SARS-CoV-2 Breakthrough Infections.

To determine neutralizing activity against the severe acute respiratory syndrome coronavirus 2 ancestral strain and 4 variants of concern, we tested serum from 30 persons with breakthrough infection after 2-dose vaccination. Cross-variant neutralizing activity was comparable to that after 3-dose vaccination. Shorter intervals between vaccination and breakthrough infection correlated with lower neutralizing titers.

Determining the reliability of rapid SARS-CoV-2 antigen detection in fully vaccinated individuals

Background Rapid antigen detection tests (RADT) are commonly used as SARS-CoV-2 diagnostic tests both by medical professionals and laypeople. However, the performance of RADT in vaccinated individuals has not been fully investigated. Objectives RT-qPCR and rapid antigen detection testing were performed to evaluate the performance of the Standard Q COVID-19 Ag Test in detecting SARS-CoV-2 breakthrough infections in vaccinated individuals. Study design Two swab specimens, one for RT-qPCR and one for RADT, were collected from vaccinated individuals in an outpatient clinic. For comparison of RADT performance in vaccinated and unvaccinated individuals, a dataset already published by this group was used as reference. Results A total of 696 samples were tested with both RT-qPCR and RADT that included 692 (99.4%) samples from vaccinated individuals. Of these, 76 (11.0%) samples were detected SARS-CoV-2 positive by RT-qPCR and 45 (6.5%) samples by the Standard Q COVID-19 Ag test. Stratified by Ct values, sensitivity of the RADT was 100.0%, 94.4% and 81.1% for Ct ≤ 20 (n=18), Ct ≤ 25 (n=36) and Ct ≤ 30 (n=53), respectively. Samples with Ct values ≥ 30 (n=23) were not detected. Overall RADT specificity was 99.7% and symptom status did not affect RADT performance. Notably, RADT detected 4 out of 4 samples of probable Omicron variant infection based on single nucleotide polymorphism analysis. Conclusion Our results show that RADT testing remains a valuable tool in detecting breakthrough infections with high viral RNA loads.

Determining the reliability of rapid SARS-CoV-2 antigen detection in fully vaccinated individuals.

BACKGROUND: Rapid antigen detection tests (RADT) are commonly used as SARS-CoV-2 diagnostic tests both by medical professionals and laypeople. However, the performance of RADT in vaccinated individuals has not been fully investigated. OBJECTIVES: RT-qPCR and rapid antigen detection testing were performed to evaluate the performance of the Standard Q COVID-19 Ag Test in detecting SARS-CoV-2 breakthrough infections in vaccinated individuals. STUDY DESIGN: Two swab specimens, one for RT-qPCR and one for RADT, were collected from vaccinated individuals in an outpatient clinic. For comparison of RADT performance in vaccinated and unvaccinated individuals, a dataset already published by this group was used as reference. RESULTS: During the delta wave, a total of 696 samples were tested with both RT-qPCR and RADT that included 692 (99.4%) samples from vaccinated individuals. Of these, 76 (11.0%) samples were detected SARS-CoV-2 positive by RT-qPCR and 45 (6.5%) samples by the Standard Q COVID-19 Ag test. Stratified by Ct values, sensitivity of the RADT was 100.0%, 94.4% and 81.1% for Ct ≤ 20 (n=18), Ct ≤ 25 (n=36) and Ct ≤ 30 (n=53), respectively. Samples with Ct values ≥ 30 (n=23) were not detected. Overall RADT specificity was 99.7% and symptom status did not affect RADT performance. Notably, RADT detected 4 out of 4 samples of probable Omicron variant infection based on single nucleotide polymorphism analysis. CONCLUSION: Our results show that RADT testing remains a valuable tool in detecting breakthrough infections with high viral RNA loads.

mRNA booster immunization elicits potent neutralizing serum activity against the SARS-CoV-2 Omicron variant.

The Omicron variant of SARS-CoV-2 is causing a rapid increase in infections across the globe. This new variant of concern carries an unusually high number of mutations in key epitopes of neutralizing antibodies on the viral spike glycoprotein, suggesting potential immune evasion. Here we assessed serum neutralizing capacity in longitudinal cohorts of vaccinated and convalescent individuals, as well as monoclonal antibody activity against Omicron using pseudovirus neutralization assays. We report a near-complete lack of neutralizing activity against Omicron in polyclonal sera from individuals vaccinated with two doses of the BNT162b2 COVID-19 vaccine and from convalescent individuals, as well as resistance to different monoclonal antibodies in clinical use. However, mRNA booster immunizations in vaccinated and convalescent individuals resulted in a significant increase of serum neutralizing activity against Omicron. This study demonstrates that booster immunizations can critically improve the humoral immune response against the Omicron variant.

Discovery of ultrapotent broadly neutralizing antibodies from SARS-CoV-2 elite neutralizers.

A fraction of COVID-19 convalescent individuals mount a potent antibody response to SARS-CoV-2 with cross-reactivity to SARS-CoV-1. To uncover their humoral response in detail, we performed single B cell analysis from 10 SARS-CoV-2 elite neutralizers. We isolated and analyzed 126 monoclonal antibodies, many of which were sarbecovirus cross-reactive, with some displaying merbecovirus- and embecovirus-reactivity. Several isolated broadly neutralizing antibodies were effective against B.1.1.7, B.1.351, B.1.429, B.1.617, and B.1.617.2 variants and 19 prominent potential escape sites. Furthermore, assembly of 716,806 SARS-CoV-2 sequences predicted emerging escape variants, which were also effectively neutralized. One of these broadly neutralizing potent antibodies, R40-1G8, is a IGHV3-53 RBD-class-1 antibody. Remarkably, cryo-EM analysis revealed that R40-1G8 has a flexible binding mode, targeting both "up" and "down" conformations of the RBD. Given the threat of emerging SARS-CoV-2 variants, we demonstrate that elite neutralizers are a valuable source for isolating ultrapotent antibody candidates to prevent and treat SARS-CoV-2 infection.

Case Report: Clinical Management of a Patient With Metastatic Non-Small Cell Lung Cancer Newly Receiving Immune Checkpoint Inhibition During Symptomatic COVID-19.

Effects of initiation of programmed-death-protein 1 (PD1) blockade during active SARS-CoV-2 infection on antiviral immunity, COVID-19 course, and underlying malignancy are unclear. We report on the management of a male in his early 40s presenting with highly symptomatic metastatic lung cancer and active COVID-19 pneumonia. After treatment initiation with pembrolizumab, carboplatin, and pemetrexed, the respiratory situation initially worsened and high-dose corticosteroids were initiated due to suspected pneumonitis. After improvement and SARS-CoV-2 clearance, anti-cancer treatment was resumed without pembrolizumab. Immunological analyses with comparison to otherwise healthy SARS-CoV-2-infected ambulatory patients revealed a strong humoral immune response with higher levels of SARS-CoV-2-reactive IgG and neutralizing serum activity. Additionally, sustained increase of Tfh as well as activated CD4+ and CD8+ T cells was observed. Sequential CT scans showed regression of tumor lesions and marked improvement of the pulmonary situation, with no signs of pneumonitis after pembrolizumab re-challenge as maintenance. At the latest follow-up, the patient is ambulatory and in ongoing partial remission on pembrolizumab. In conclusion, anti-PD1 initiation during active COVID-19 pneumonia was feasible and cellular and humoral immune responses to SARS-CoV-2 appeared enhanced in our hospitalized patient. However, distinguishing COVID-19-associated changes from anti-PD1-associated immune-related pneumonitis posed a considerable clinical, radiographic, and immunologic challenge.

Safety, reactogenicity, and immunogenicity of homologous and heterologous prime-boost immunisation with ChAdOx1 nCoV-19 and BNT162b2: a prospective cohort study.

BACKGROUND: Heterologous vaccine regimens have been widely discussed as a way to mitigate intermittent supply shortages and to improve immunogenicity and safety of COVID-19 vaccines. We aimed to assess the reactogenicity and immunogenicity of heterologous immunisations with ChAdOx1 nCov-19 (AstraZeneca, Cambridge, UK) and BNT162b2 (Pfizer-BioNtech, Mainz, Germany) compared with homologous BNT162b2 and ChAdOx1 nCov-19 immunisation. METHODS: This is an interim analysis of a prospective observational cohort study enrolling health-care workers in Berlin (Germany) who received either homologous ChAdOx1 nCov-19 or heterologous ChAdOx1 nCov-19-BNT162b2 vaccination with a 10-12-week vaccine interval or homologous BNT162b2 vaccination with a 3-week vaccine interval. We assessed reactogenicity after the first and second vaccination by use of electronic questionnaires on days 1, 3, 5, and 7. Immunogenicity was measured by the presence of SARS-CoV-2-specific antibodies (full spike-IgG, S1-IgG, and RBD-IgG), by an RBD-ACE2 binding inhibition assay (surrogate SARS-CoV-2 virus neutralisation test), a pseudovirus neutralisation assay against two variants of concerns (alpha [B.1.1.7] and beta [B.1.351]), and anti-S1-IgG avidity. T-cell reactivity was measured by IFN-γ release assay. FINDINGS: Between Dec 27, 2020, and June 14, 2021, 380 participants were enrolled in the study, with 174 receiving homologous BNT162b2 vaccination, 38 receiving homologous ChAdOx1 nCov-19 vaccination, and 104 receiving ChAdOx1 nCov-19-BNT162b2 vaccination. Systemic symptoms were reported by 103 (65%, 95% CI 57·1-71·8) of 159 recipients of homologous BNT162b2, 14 (39%, 24·8-55·1) of 36 recipients of homologous ChAdOx1 nCov-19, and 51 (49%, 39·6-58·5) of 104 recipients of ChAdOx1 nCov-19-BNT162b2 after the booster immunisation. Median anti-RBD IgG levels 3 weeks after boost immunisation were 5·4 signal to cutoff ratio (S/co; IQR 4·8-5·9) in recipients of homologous BNT162b2, 4·9 S/co (4·3-5·6) in recipients of homologous ChAdOx1 nCov-19, and 5·6 S/co (5·1-6·1) in recipients of ChAdOx1 nCov-19- BNT162b2. Geometric mean of 50% inhibitory dose against alpha and beta variants were highest in recipients of ChAdOx1 nCov-19-BNT162b2 (956·6, 95% CI 835·6-1095, against alpha and 417·1, 349·3-498·2, against beta) compared with those in recipients of homologous ChAdOx1 nCov-19 (212·5, 131·2-344·4, against alpha and 48·5, 28·4-82·8, against beta; both p<0·0001) or homologous BNT162b2 (369·2, 310·7-438·6, against alpha and 72·4, 60·5-86·5, against beta; both p<0·0001). SARS-CoV-2 S1 T-cell reactivity 3 weeks after boost immunisation was highest in recipients of ChAdOx1 nCov-19-BNT162b2 (median IFN-γ concentration 4762 mIU/mL, IQR 2723-8403) compared with that in recipients of homologous ChAdOx1 nCov-19 (1061 mIU/mL, 599-2274, p<0·0001) and homologous BNT162b2 (2026 mIU/mL, 1459-4621, p=0·0008) vaccination. INTERPRETATION: The heterologous ChAdOx1 nCov-19-BNT162b2 immunisation with 10-12-week interval, recommended in Germany, is well tolerated and improves immunogenicity compared with homologous ChAdOx1 nCov-19 vaccination with 10-12-week interval and BNT162b2 vaccination with 3-week interval. Heterologous prime-boost immunisation strategies for COVID-19 might be generally applicable. FUNDING: Forschungsnetzwerk der Universitätsmedizin zu COVID-19, the German Ministry of Education and Research, Zalando SE.