Incidence of symptomatic Covid-19 infections in patients with mastocytosis and chronic myeloid leukemia: A comparison with the general Austrian population.

BACKGROUND: The SARS-COV-2 (Covid-19) pandemic has impacted the management of patients with hematologic disorders. In some entities, an increased risk for Covid-19 infections was reported, whereas others including chronic myeloid leukemia (CML) had a lower mortality. We have analyzed the prevalence of Covid-19 infections in patients with mastocytosis during the Covid-19 pandemic in comparison to data from CML patients and the general Austrian population. MATERIALS AND METHODS: The prevalence of infections and PCR-proven Covid-19 infections was analyzed in 92 patients with mastocytosis. As controls, we used 113 patients with CML and the expected prevalence of Covid-19 in the general Austrian population. RESULTS: In 25% of the patients with mastocytosis (23/92) signs and symptoms of infection, including fever (n = 11), dry cough (n = 10), sore throat (n = 12), pneumonia (n = 1), and dyspnea (n = 3) were recorded. Two (8.7%) of these symptomatic patients had a PCR-proven Covid-19 infection. Thus, the prevalence of Covid-19 infections in mastocytosis was 2.2%. The number of comorbidities, subtype of mastocytosis, regular exercise, smoking habits, age, or duration of disease at the time of interview did not differ significantly between patients with and without Covid-19 infections. In the CML cohort, 23.9% (27/113) of patients reported signs and symptoms of infection (fever, n = 8; dry cough, n = 17; sore throat, n = 11; dyspnea, n = 5). Six (22.2%) of the symptomatic patients had a PCR-proven Covid-19 infection. The prevalence of Covid-19 in all CML patients was 5.3%. The observed number of Covid-19 infections neither in mastocytosis nor in CML patients differed significantly from the expected number of Covid-19 infections in the Austrian population. CONCLUSIONS: Our data show no significant difference in the prevalence of Covid-19 infections among patients with mastocytosis, CML, and the general Austrian population and thus, in mastocytosis, the risk of a Covid-19 infection was not increased compared to the general population.

Full seroconversion in initial non-responders with higher antibody levels after heterologous COVID-19 vaccination schedule.

Antibody testing after COVID-19 vaccination is generally not recommended. Here, we present the results of a retrospective study, in which we analyzed antibody levels before and after the first dose of the ChAdOx1 vector vaccine. We identified 5% non-responders (43.6 ± 10.6 years; females: 41%) and 3.4% low-responders (44.2 ± 10.1 years; females: 64%) after the first dose. Of these, 61 individuals received a timely second dose either with a homologous (ChAdOx1/ChAdOx1) or heterologous (ChAdOx1/mRNA-1273) schedule. All vaccinees achieved positive S1-specific IgG titers to the ancestral SARS-CoV-2 strain after the second dose, but antibody levels as well as neutralization titers against the ancestral SARS-CoV-2 strain were higher after the heterologous schedule. However, Omicron-specific neutralizing antibodies were not detectable after two doses in either group, indicating that a third vaccine dose is needed to enhance cross-reactive antibodies against currently circulating and emerging variants of concern.

Combined assessment of S- and N-specific IL-2 and IL-13 secretion and CD69 neo-expression for discrimination of post-infection and post-vaccination cellular SARS-CoV-2-specific immune response.

BACKGROUND: Antibody-based tests are available for measuring SARS-CoV-2-specific immune responses but fast T-cell assays remain scarce. Robust T cell-based tests are needed to differentiate specific cellular immune responses after infection from those after vaccination. METHODS: One hundred seventeen individuals (COVID-19 convalescent patients: n = 40; SARS-CoV-2 vaccinees: n = 41; healthy controls: n = 36) were evaluated for SARS-CoV-2-specific cellular immune responses (proliferation, Th1, Th2, Th17, and inflammatory cytokines, activation-induced marker [AIM] expression) by incubating purified peripheral blood mononuclear cells (PBMC) or whole blood (WB) with SARS-CoV-2 peptides (S, N, or M), vaccine antigens (tetanus toxoid, tick borne encephalitis virus) or polyclonal stimuli (Staphylococcal enterotoxin, phytohemagglutinin). RESULTS: N-peptide mix stimulation of WB identified the combination of IL-2 and IL-13 secretion as superior to IFN-γ secretion to discriminate between COVID-19-convalescent patients and healthy controls (p < .0001). Comparable results were obtained with M- or S-peptides, the latter almost comparably recalled IL-2, IFN-γ, and IL-13 responses in WB of vaccinees. Analysis 10 months as opposed to 10 weeks after COVID-19, but not allergic disease status, positively correlated with IL-13 recall responses. WB cytokine responses correlated with cytokine and proliferation responses of PBMC. Antigen-induced neo-expression of the C-type lectin CD69 on CD4+ (p < .0001) and CD8+ (p = .0002) T cells informed best about the SARS-CoV-2 exposure status with additional benefit coming from CD25 upregulation. CONCLUSION: Along with N- and S-peptide-induced IL-2 and CD69 neo-expression, we suggest to include the type 2 cytokine IL-13 as T-cellular recall marker for SARS-CoV-2 specific T-cellular immune responses after infection and vaccination.

SARS-CoV-2-mRNA Booster Vaccination Reverses Non-Responsiveness and Early Antibody Waning in Immunocompromised Patients - A Phase Four Study Comparing Immune Responses in Patients With Solid Cancers, Multiple Myeloma and Inflammatory Bowel Disease.

Background: Individuals with secondary immunodeficiencies belong to the most vulnerable groups to succumb to COVID-19 and thus are prioritized for SARS-CoV-2 vaccination. However, knowledge about the persistence and anamnestic responses following SARS-CoV-2-mRNA vaccinations is limited in these patients. Methods: In a prospective, open-label, phase four trial we analyzed S1-specific IgG, neutralizing antibodies and cytokine responses in previously non-infected patients with cancer or autoimmune disease during primary mRNA vaccination and up to one month after booster. Results: 263 patients with solid tumors (SOT, n=63), multiple myeloma (MM, n=70), inflammatory bowel diseases (IBD, n=130) and 66 controls were analyzed. One month after the two-dose primary vaccination the highest non-responder rate was associated with lower CD19+ B-cell counts and was found in MM patients (17%). S1-specific IgG levels correlated with IL-2 and IFN-γ responses in controls and IBD patients, but not in cancer patients. Six months after the second dose, 18% of patients with MM, 10% with SOT and 4% with IBD became seronegative; no one from the control group became negative. However, in IBD patients treated with TNF-α inhibitors, antibody levels declined more rapidly than in controls. Overall, vaccination with mRNA-1273 led to higher antibody levels than with BNT162b2. Importantly, booster vaccination increased antibody levels >8-fold in seroresponders and induced anamnestic responses even in those with undetectable pre-booster antibody levels. Nevertheless, in IBD patients with TNF-α inhibitors even after booster vaccination, antibody levels were lower than in untreated IBD patients and controls. Conclusion: Immunomonitoring of vaccine-specific antibody and cellular responses seems advisable to identify vaccination failures and consequently establishing personalized vaccination schedules, including shorter booster intervals, and helps to improve vaccine effectiveness in all patients with secondary immunodeficiencies. Trial registration: EudraCT Number: 2021-000291-11.

Neutralising SARS-CoV-2 RBD-specific antibodies persist for at least six months independently of symptoms in adults.

Background: In spring 2020, at the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Europe, we set up an assay system for large-scale testing of virus-specific and neutralising antibodies including their longevity. Methods: We analysed the sera of 1655 adult employees for SARS-CoV-2-specific antibodies using the S1 subunit of the spike protein of SARS-CoV-2. Sera containing S1-reactive antibodies were further evaluated for receptor-binding domain (RBD)- and nucleocapsid protein (NCP)-specific antibodies in relation to the neutralisation test (NT) results at three time points over six months. Results: We detect immunoglobulin G (IgG) and/or IgA antibodies reactive to the S1 protein in 10.15% (n = 168) of the participants. In total, 0.97% (n = 16) are positive for S1-IgG, 0.91% (n = 15) were S1-IgG- borderline and 8.28% (n = 137) exhibit only S1-IgA antibodies. Of the 168 S1-reactive sera, 8.33% (n = 14) have detectable RBD-specific antibodies and 6.55% (n = 11) NCP-specific antibodies. The latter correlates with NTs (kappa coefficient = 0.8660) but start to decline after 3 months. RBD-specific antibodies correlate most closely with the NT (kappa = 0.9448) and only these antibodies are stable for up to six months. All participants with virus-neutralising antibodies report symptoms, of which anosmia and/or dysgeusia correlate most closely with the detection of virus-neutralising antibodies. Conclusions: RBD-specific antibodies are most reliably detected post-infection, independent of the number/severity of symptoms, and correlate with neutralising antibodies at least for six months. They thus qualify best for large-scale seroepidemiological evaluation of both antibody reactivity and virus neutralisation.

SARS-CoV-2-Specific Antibody (Ab) Levels and the Kinetic of Ab Decline Determine Ab Persistence Over 1 Year.

In a SARS-CoV-2 seroprevalence study conducted with 1,655 working adults in spring of 2020, 12 of the subjects presented with positive neutralization test (NT) titers (>1:10). They were here followed up for 1 year to assess their Ab persistence. We report that 7/12 individuals (58%) had NT_50 titers ≥1:50 and S1-specific IgG ≥50 BAU/ml 1 year after mild COVID-19 infection. S1-specific IgG were retained until a year when these levels were at least >60 BAU/ml at 3 months post-infection. For both the initial fast and subsequent slow decline phase of Abs, we observed a significant correlation between NT_50 titers and S1-specific IgG and thus propose S1-IgG of 60 BAU/ml 3 months post-infection as a potential threshold to predict neutralizing Ab persistence for 1 year. NT_50 titers and S1-specific IgG also correlated with circulating S1-specific memory B-cells. SARS-CoV-2-specific Ab levels after primary mRNA vaccination in healthy controls were higher (Geometric Mean Concentration [GMC] 3158 BAU/ml [CI 2592 to 3848]) than after mild COVID-19 infection (GMC 82 BAU/ml [CI 48 to 139]), but showed a stronger fold-decline within 5-6 months (0.20-fold, to GMC 619 BAU/ml [CI 479 to 801] vs. 0.56-fold, to GMC 46 BAU/ml [CI 26 to 82]). Of particular interest, the decline of both infection- and vaccine-induced Abs correlated with body mass index. Our data contribute to describe decline and persistence of SARS-CoV-2-specific Abs after infection and vaccination, yet the relevance of the maintained Ab levels for protection against infection and/or disease depends on the so far undefined correlate of protection.

Low SARS-CoV-2 seroprevalence in the Austrian capital after an early governmental lockdown.

We analyzed SARS-CoV-2 seroprevalence in a large, well-described representative Viennese cohort after an early governmental lockdown with respect to the occurrence of symptoms and household transmission. Participants of the LEAD Study, a population-based cohort study from Vienna, Austria, were invited along with their household members (April 20th to May20th 2020). Sera were analyzed using anti-SARS-CoV-2 immunoassay including a neutralization test as a confirmatory assay. A total of 12,419 individuals participated (5984 LEAD participants; 6435 household members), 163 (1.31%; 59 LEAD cohort members) of whom were SARS-CoV-2 antibody positive. The estimated number of COVID-19 cases projected from our findings by age and sex for Vienna was 21,504 (1.13%). Cumulative number of positively tested cases in Vienna until May 20th 2020 was 3020, hence 7.1 times (95% confidence interval 5.5-9.1) lower than projected. Relative risk (RR) of seropositivity by age was highest for children aged 6-9 years [RR compared to age group 20-49: 1.21 (CI 0.37-4.01)], lowest for ≥ 65 years [RR 0.47 (CI 0.21-1.03)]. Half of the positive individuals developed no or mild symptoms. In a multivariate analysis, taste and smell disturbances were most strongly related to SARS-CoV-2 positivity. Infection probability within households with one confirmed SARS-CoV-2-specific antibody-positive person was 31%. Although seroprevalence was very low (1.13%) for a central European capital city, due to an early governmental lockdown, SARS-CoV-2 infections were more prevalent than officially reported polymerase chain reaction-positive cases. Of note, seroprevalence was highest in young children. Half of SARS-CoV-2 antibody-positive subjects had no or only mild symptoms. Taste and smell disturbances were most prominent, possibly guiding clinicians in diagnosing SARS-CoV-2 infection.

Significant impact of nationwide SARS-CoV-2 lockdown measures on the circulation of other respiratory virus infections in Austria.

BACKGROUND: Since the worldwide spread of SARS-CoV-2, different European countries reacted with temporary national lockdowns with the aim to limit the virus transmission in the population. Also Austria started a lockdown of public life in March 2020. OBJECTIVES: In this study we investigated whether the circulation of different respiratory virus infections in Austria, as assessed by the established respiratory virus surveillance system, is affected by these measures as well and may reflect the success of the lockdown in limiting respiratory virus transmission. STUDY DESIGN: Sentinel data obtained for influenza virus, respiratory syncytial virus, human metapneumovirus and rhinovirus cases were analyzed and compared between the season 2019/2020 and the five previous seasons. RESULTS: We observed a rapid and statistically significant reduction of cumulative cases for all these viruses within short time after the lockdown in March 2020, compared to previous seasons (each p < 0.001). Also, sentinel screening for SARS-CoV-2 infections was performed and a decrease of SARS-CoV-2 was seen after the lockdown. While for the seasonally occurring viruses as influenza, respiratory syncytial virus or human metapneumovirus the lockdown led to the end of the annual epidemics, a re-increase of rhinovirus infections was observed after liberalization of numerous lockdown measures. CONCLUSIONS: Our data provide evidence that occurrence of different respiratory virus infections reflect not only the efficiency of lockdown measures taken against SARS-CoV-2 but it shows also the effects of lockdown releases on the transmission of respiratory viruses.

Air Pollution Is Associated with COVID-19 Incidence and Mortality in Vienna, Austria.

We determined the impact of air pollution on COVID-19-related mortality and reported-case incidence, analyzing the correlation of infection case numbers and outcomes with previous-year air pollution data from the populations of 23 Viennese districts. Time at risk started in a district when the first COVID-19 case was diagnosed. High exposure levels were defined as living in a district with an average (year 2019) concentration of nitrogen dioxide (NO2) and/or particulate matter (PM10) higher than the upper quartile (30 and 20 µg/m3, respectively) of all districts. The total population of the individual districts was followed until diagnosis of or death from COVID-19, or until 21 April 2020, whichever came first. Cox proportional hazard regression was performed after controlling for percentage of population aged 65 and more, percentage of foreigners and of persons with a university degree, unemployment rate, and population density. PM10 and NO2 were significantly and positively associated with the risk of a COVID-19 diagnosis (hazard ratio (HR) = 1.44 and 1.16, respectively). NO2 was also significantly associated with death from COVID-19 (HR = 1.72). Even within a single city, higher levels of air pollution are associated with an adverse impact on COVID-19 risk.

Dynamics of CD4 T Cell and Antibody Responses in COVID-19 Patients With Different Disease Severity.

Disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ranges from mild illness to severe respiratory disease and death. In this study, we determined the kinetics of viral loads, antibody responses (IgM, IgG, neutralization) and SARS-CoV-2-specific CD4 T cells by quantifying these parameters in 435 serial respiratory and blood samples collected from a cohort of 29 COVID-19 patients with either moderate or severe disease during the whole period of hospitalization or until death. Remarkably, there was no significant difference in the kinetics and plateau levels of neutralizing antibodies among the groups with different disease severity. In contrast, the dynamics of specific CD4 T cell responses differed considerably, but all patients with moderate or severe disease developed robust SARS-CoV-2-specific responses. Of note, none of the patients had detectable cross-reactive CD4 T cells in the first week after symptom onset, which have been described in 20-50% of unexposed individuals. Our data thus provide novel insights into the kinetics of antibody and CD4 T cell responses as well as viral loads that are key to understanding the role of adaptive immunity in combating the virus during acute infection and provide leads for the timing of immune therapies for COVID-19.