Wild ungulates as sentinels of flaviviruses and tick-borne zoonotic pathogen circulation: an Italian perspective.

BACKGROUND: Vector-borne zoonotic diseases are a concerning issue in Europe. Lyme disease and tick-borne encephalitis virus (TBEV) have been reported in several countries with a large impact on public health; other emerging pathogens, such as Rickettsiales, and mosquito-borne flaviviruses have been increasingly reported. All these pathogens are linked to wild ungulates playing roles as tick feeders, spreaders, and sentinels for pathogen circulation. This study evaluated the prevalence of TBEV, Borrelia burgdorferi sensu lato, Rickettsia spp., Ehrlichia spp., and Coxiella spp. by biomolecular screening of blood samples and ticks collected from wild ungulates. Ungulates were also screened by ELISA and virus neutralization tests for flaviviral antibody detection. RESULTS: A total of 274 blood samples were collected from several wild ungulate species, as well as 406 Ixodes ricinus, which were feeding on them. Blood samples tested positive for B. burgdorferi s.l. (1.1%; 0-2.3%) and Rickettsia spp. (1.1%; 0-2.3%) and showed an overall flaviviral seroprevalence of 30.6% (22.1-39.2%): 26.1% (17.9-34.3%) for TBEV, 3.6% (0.1-7.1%) for Usutu virus and 0.9% (0-2.7%) for West Nile virus. Ticks were pooled when possible and yielded 331 tick samples that tested positive for B. burgdorferi s.l. (8.8%; 5.8-11.8%), Rickettsia spp. (26.6%; 21.8-31.2%) and Neoehrlichia mikurensis (1.2%; 0-2.4%). TBEV and Coxiella spp. were not detected in either blood or tick samples. CONCLUSIONS: This research highlighted a high prevalence of several tick-borne zoonotic pathogens and high seroprevalence for flaviviruses in both hilly and alpine areas. For the first time, an alpine chamois tested positive for anti-TBEV antibodies. Ungulate species are of particular interest due to their sentinel role in flavivirus circulation and their indirect role in tick-borne diseases and maintenance as Ixodes feeders and spreaders.

Third dose of COVID-19 vaccine restores immune response in patients with haematological malignancies after loss of protective antibody titres.

We have vaccinated 392 patients with two doses of mRNA COMIRNATY vaccine with an overall antibody response of 70% (best in cMPN, worst in CLL). We have then vaccinated 80 patients who did not achieve seroconversion or were low responders with a third dose of COMIRNATY vaccine. Our first results show promise, especially for patients on anti-CD38 therapy.

COVID-19 antibody testing: examination of the antibody response to coronavirus in common practice.

Antibody identification is an important diagnostic tool that allows us to confirm a past SARS-CoV-2 infection. While antibody tests in the Czech Republic are yet to receive the attention they deserve, in the USA antibody testing has already become part of the diagnostic algorithms. The aim of this publication is to provide comprehensive information on the topic of antibody testing, the kinetics of antibody production, the types of tests and the issue of virus neutralization tests. Special attention is paid to the correct interpretation of test results and the issues surrounding reinfection.

What is the immunity of high school students to coronavirus?

Children and young people are at the least risk of coronavirus infection and the consequences of COVID-19. However, COVID-19 has dramatically affected their lives due to many months of school closures intended to prevent the spread of the infection. In the Czech Republic, secondary schools were closed from 14 October 2020 to 24 May 2021 with a short break before Christmas. However, the students were most often infected by their parents, who usually became infected at work. The aim of this study was to find out by means of antibody testing how many high school students in Havlíčkův Brod have undergone the infection. We used questionnaires to find out how many students were in quarantine. The group included 196 students aged 15-19. Examination of IgG antibodies against the S antigen (Abbott, Architect) was performed in June 2021. Antibodies were detected in 90 of 196 students (45.9%). Coronavirus infection was reported in 88 families. Antibodies were detected in 61 quarantined students (69.3%), while the remaining 27 students had neither antibodies, nor clinical signs, nor positive PCR test. Thus, these students are considered unsusceptible to the infection at the time of quarantine. Despite the interruption of teaching in schools and the associated reduction of contacts, a significant share of students met with the coronavirus. About half of the students in the sample are already largely resistant to the disease (have antibodies). Another part of the students was unsusceptible to the disease, because they did not fall sick despite having been in contact with an infected family member.

Antibodies from previous infection bring sufficient and long-term protection against COVID-19.

One of the basic manifestations of an adaptive anti-infective immunity is the production of specific antibodies. The presence of antibodies can be detected in serum and serves as one of the diagnostic tools used to confirm past infection. Very often it also serves as a confirmation that the body has acquired immunity to the disease. The appearance of COVID-19 has cast a shadow of doubt on these textbook examples of antibody behavior. Information that repeatedly questions antibody measurement and its significance has been circulating among professionals and the general public. The aim of our article is to summarize the current knowledge on the immunity acquired following SARS-CoV-2 infection and to present the results of antibody testing from four Czech laboratories which have been measuring these antibodies for over one year. Our data suggest that commonly available diagnostic methods reliably predict the results of a virus neutralization test, which is the gold standard of immunity detection. By acknowledging those with naturally acquired anti-infective immunity, in addition to vaccinated individuals, we will significantly increase the perceived level of collective immunity.

Age is not a disease: Evolution of protective antibodies against SARS-CoV-2 in seniors from the Břevnice nursing home.

In the nursing home in Břevnice, 21 out of 23 seniors were infected with the SARS-CoV-2 virus in the spring of 2020. Three of them died from the infection. This study monitors the antibodies formation in group of seniors who have overcome the infection. Between April and November (1-8 months after the infection), the antibodies were measured repeatedly within the period of several weeks. The virus neutralizing tests was used as well as the ECLIA assay by Roche (total immunoglobulins), CMIA assay by Abbott (IgG) and ELISA assay by Euroimmun (IgG and IgA). Six months from the infection, neutralizing antibodies were detected in 18 out of 20 seniors. High levels of neutralizing antibodies correlated with higher levels of immunoglobulins and were a good predictor of an increase of IgG in the autumn during the second wave of the epidemic in the Czech Republic. During the autumn wave, neither any of the clients, nor any staff contracted the virus, although the prevalence of PCR positivity in the Vysočina region reached around 5 %. The antigen tests also came out all negative. This study shows that in the senior population, the production of protective antibodies follows a normal pattern, and the seniors are probably immune to a repeated infection for at least 8 months from the first infection. Based on these results, we would like to open the discussion on the testing for seroprevalence in nursing homes, possible changes to the epidemiologic regime in relation to the risk of infection, and about vaccination schemes in these centers.

Molecular Epidemiology of Hantaviruses in the Czech Republic.

During 2008-2018, we collected samples from rodents and patients throughout the Czech Republic and characterized hantavirus isolates. We detected Dobrava-Belgrade and Puumala orthohantaviruses in patients and Dobrava-Belgrade, Tula, and Seewis orthohantaviruses in rodents. Increased knowledge of eco-epidemiology of hantaviruses will improve awareness among physicians and better outcomes of patients.

Serological survey of measles immunity in the Czech Republic, 2013.

OBJECTIVES: The aim of the serological survey of measles was to obtain information on the prevalence of antibodies against measles and to verify the effectiveness of vaccination in the Czech population in order to protect public health. METHODS: The serological survey was carried out in the Czech Republic in 2013. Antibodies against measles were tested in 3,111 serum samples of participants aged 1-64 years. Serum samples were tested for the presence of immunoglobulin G (IgG) antibodies by enzyme immunoassay (EIA). The vaccination status assessment was based on the medical documentation. Seroprevalence differences were evaluated by sex and age using the Pearson's χ2 test at 5% significance level. RESULTS: The overall seroprevalence reached 93.0% (2,893/3,111) (95% CI 92.0-93.9). No statistically significant difference was found between men and women (p=0.724). A lower seroprevalence was identified in the first age group (1-year old children) 62% (62/100), as the vaccination has not yet been completed in this age group. The second lowest seroprevalence 80.4% (160/199) was identified in the age group of 35-44 years. The highest seroprevalence 97.7% (387/396) (95% CI 95.7-99.0) was in the population with naturally-induced immunity (age above 45 years). In the individuals with two doses seroprevalence reached 94.1% (2,081/2,212) (95% CI 93.0-95.0). The level of IgG antibodies decreased in persons above 7 years of age. CONCLUSIONS: Based on the results of the serological survey carried out in 2013 in the Czech Republic, it has been decided to postpone the second MMR (measles, mumps and rubella) dose to the age of 5-6 years.

Sensitivity and Kinetics of an NS1-Based Zika Virus Enzyme-Linked Immunosorbent Assay in Zika Virus-Infected Travelers from Israel, the Czech Republic, Italy, Belgium, Germany, and Chile.

Serological diagnosis of Zika virus is challenging due to high cross-reactivity of Zika virus with other flavivirus antibodies. Recently, a Zika NS1-based enzyme-linked immunosorbent assay (ELISA) was developed and shown to be highly specific for Zika antibody detection; however, sensitivity was evaluated for only a small number of confirmed Zika-infected patients. In this study, we measured the sensitivity and kinetics of Zika IgM and IgG antibodies using the Zika NS1-based ELISA in 105 samples from 63 returning travelers infected with Zika virus (proven by PCR or neutralization assay) from Israel, Czech Republic, Italy, Belgium, Germany, and Chile. Zika virus IgM was detected from 2 to 42 days post-symptom onset (PSO) with an overall sensitivity of 79% in the first month and 68% until 2 months PSO, while IgG antibodies were detected from 5 days to 3 years PSO with 79% sensitivity. Interestingly, significant differences in IgM sensitivity and IgM detection period were observed between Israeli and European/Chilean Zika-infected travelers, adding to the complexity of Zika infection diagnosis and suggesting that other diagnostic methods should be complemented to reduce false-negative results.

[Concurrent malaria and rickettsiosis in a patient returning from the Republic of South Africa].

Definitive diagnosis and therapy proved challenging in the case of a 60-year-old male with malaria and rickettsiosis. Returning travellers who are unwell can present practical difficulties in diagnosis and treatment and the focus here is on conditions relevant to the Republic of South Africa. Malaria, rickettsiosis and Q fever are discussed.

Tula hantavirus infection in immunocompromised host, Czech Republic.

We report molecular evidence of Tula hantavirus as an etiologic agent of pulmonary-renal syndrome in an immunocompromised patient. Acute hantavirus infection was confirmed by using serologic and molecular methods. Sequencing revealed Tula virus genome RNA in the patient's blood. This case shows that Tula virus can cause serious disease in humans.

[Dengue fever cases in Czech workers returning from the Maldives]. / Prípady horecky dengue u ceských pracovníku zamestnaných na Maledivách.

AIM: The objective of this study is to present epidemiological characteristics and clinical symptoms of dengue fever cases in Czech workers who acquired the infection while working on the island of Fushivelavaru, Maldives. Furthermore, the study compares the sensitivity of novel direct detection assays, i.e. Real-Time Polymerase Chain Reaction (RT-PCR) and detection of Dengue NS1 antigen. MATERIAL AND METHODS: The retrospective study evaluated the clinical course of dengue fever cases in Czech workers returning from a job in the Maldives who were diagnosed with dengue virus infection from September 1 to October 31, 2012. The laboratory diagnosis of dengue fever was based on the serological detection of IgM and IgG antibodies, detection of dengue NS1 antigen by enzyme-linked immunosobent assay (ELISA), and detection of dengue virus DNA by RT-PCR. RESULTS: The infection with dengue virus was confirmed in 18 males with a median age of 40 years (IQR 36-47) who returned from a job in the Maldives. Only one patient required admission to the hospital while the others were treated on an outpatient basis. The most frequently observed symptoms were fever (18), headache (9), muscle and joint pain (8 and 7, respectively), and rash (9). Typical laboratory findings were leukocytopenia and thrombocytopenia, a low CRP level, and elevated aminotransferase activity. The clinical course was uncomplicated in all patients. The dengue NS1 antigen detection (positive in all 10 patients with acute dengue fever) showed significantly higher sensitivity than the detection of viral RNA using RT-PCR (positive in 4 patients), p = 0.011. CONCLUSION: Although the vast majority of dengue fever cases are diagnosed among travellers returning from the tropics, the presented study points out the risks posed by dengue fever to long-term workers in endemic areas. The infection in the serologically naïve hosts is usually uncomplicated; however, infected persons are at significant risk of developing a severe complicated clinical course if challenged by another serotype. Furthermore, sick leaves or premature departures cause a considerable economic burden to employers. In the diagnosis of acute dengue fever, preference should be given to highly sensitive and specific tests for the direct detection of dengue virus (NS1 antigen and RT-PCR assays).

Content and specificity of the Anti-SARS-CoV-2 antibodies in solutions for immunoglobulin replacement therapy.

BACKGROUND: Specific antibodies are important for post-vaccination and post-infection immune responses against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The role of antibodies in preventing and treating Coronavirus disease 2019 (COVID-19) in high-risk populations has been highlighted through the use of virus-specific monoclonal antibodies, which has raised the question of immunoglobulin replacement therapy (IRT) used in immunocompromised patients. METHODS: Virus-specific anti-receptor-binding domain (RBD) and anti-nucleocapsid protein (NCAP) antibodies (assessed using a chemiluminescence assay and virus-neutralizing antibodies (virus neutralization test against Delta and Omicron variants)) were analyzed in 20 batches of 10 % (100 mg/mL) immunoglobulin solutions for intravenous IRT from two commercially available producers between January 2022 and March 2023 for clinical use. RESULTS: Anti-RBD and anti-NCAP antibodies were detected in all 20 batches of assessed IRT solutions (mean concentrations of 2817 IU/mL and 2380 IU/mL, respectively). Notably, the concentration of the virus-specific antibodies increased continuously during the follow-up period (from 822.5 IU/mL to 4066.4 IU/mL and 102 IU/mL to 3455.9 IU/mL). These antibodies demonstrated high virus-neutralizing activity against the Delta variant (mean titers of 436 and 325) but were limited to the Omicron variant (mean titers 78 and 70). The differences observed between the two brands were not statistically significant. CONCLUSION: IRT solutions contain high concentrations of anti-SARS-CoV-2 specific antibodies, which may prevent COVID-19; however, the efficacy can be influenced by variable virus-neutralizing activities against different viral strains. Therefore, appropriate IRT should be combined with other approaches, such as vaccination or pre- and post-exposure prophylaxis. Passively transmitted specific antibodies may also lead to false-positive serological test results.

Epidemiology of dengue, chikungunya and Zika virus infections in travellers: A 16-year retrospective descriptive study at a tertiary care centre in Prague, Czech Republic.

INTRODUCTION: This study aims to describe the epidemiological characteristics of imported cases of dengue (DEN), chikungunya (CHIK), and Zika virus (ZIKV) infections in Czech travellers. MATERIALS AND METHODS: This single-centre descriptive study has retrospectively analysed data of patients with laboratory confirmed DEN, CHIK, and ZIKV infections diagnosed at the Department of Infectious, Parasitic and Tropical Diseases of the University Hospital Bulovka in Prague, Czech Republic from 2004 to 2019. RESULTS: The study included a total of 313 patients with DEN, 30 with CHIK, and 19 with ZIKV infections. Most patients travelled as tourists:263 (84.0%), 28 (93.3%), and 17 (89.5%), respectively (p = 0.337). The median duration of stay was 20 (IQR 14-27), 21 (IQR 14-29), and 15 days (IQR 14-43), respectively (p = 0.935). Peaks of imported DEN and ZIKV infections were noted in 2016, and in 2019 in the case of CHIK infection. Most cases of DEN and CHIKV infections were acquired in Southeast Asia:212 (67.7%) and 15 (50%), respectively, while ZIKV infection was most commonly imported from the Caribbean (11; 57,9%). CONCLUSIONS: Arbovirus infections represent an increasingly significant cause of illness in Czech travellers. Comprehensive knowledge of the specific epidemiological profile of these diseases is an essential prerequisite for good travel medicine practice.

Comparison of Two Commercially Available Interferon-γ Release Assays for T-Cell-Mediated Immunity and Evaluation of Humoral Immunity against SARS-CoV-2 in Healthcare Workers.

Cellular immunity against SARS-CoV-2 is an important component of the immune response to the virus. At present, two such tests based on interferon-gamma release (interferon-γ release assays, IGRAs) are available-Quan-T-Cell SARS-CoV-2 by EUROIMMUN and T-SPOT.COVID by Oxford Immunotec. In this paper, we compared the results of these two tests in 90 subjects employed at the Public Health Institute Ostrava who had previously undergone COVID-19 infection or were vaccinated against that disease. To the best of our knowledge, this is the first head-to-head comparison of these two tests evaluating T-cell-mediated immunity against SARS-CoV-2. In addition, we also evaluated humoral immunity in the same individuals using the in-house virus neutralization test and IgG ELISA assay. The evaluation yielded similar results for both IGRAs, with Quan-T-Cell appearing to be insignificantly (p = 0.08) more sensitive (all 90 individuals were at least borderline positive) than T-SPOT.COVID (negative results found in five patients). The overall qualitative (presence/absence of immune response) agreement of both tests with virus neutralization test and anti-S IgG was also excellent (close or equal to 100% in all subgroups, with the exception of unvaccinated Omicron convalescents, a large proportion of whom, i.e., four out of six subjects, were IgG negative while at least borderline positive for T-cell-mediated immunity measured by Quan-T). This implies that the evaluation of T-cell-mediated immunity is a more sensitive indicator of immune response than the evaluation of IgG seropositivity. This is true at least for unvaccinated patients with a history of being infected only by the Omicron variant, but also likely for other groups of patients.

Clinical Outcomes, Immunogenicity, and Safety of BNT162b2 Vaccine in Primary Antibody Deficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is characterized by an impaired postvaccination response, high susceptibility to respiratory tract infections, and a broad spectrum of noninfectious complications. Thus, patients with CVID may be at high risk for COVID-19, and vaccination's role in prevention is questionable. OBJECTIVE: We evaluated the clinical outcomes, safety, and dynamics of humoral and T-cell immune responses induced by the mRNA vaccine BNT162b2 in CVID. METHODS: This prospective observational cohort study focused on the clinical outcomes (proportion of infected patients and disease severity), safety (incidences of adverse events and changes in laboratory parameters), and dynamics of humoral (specific postvaccination and virus-neutralizing antibody assessment) and T-cell immune responses (anti-SARS-CoV-2-specific T-cell detection) in 21 patients with CVID after a two-dose administration of BNT162b2. The patients were observed for 6 months. RESULTS: Humoral response was observed in 52% of patients (11 of 21) at month 1 after vaccination but continuously decreased to 33.3% at month 6 (five of 15). Nevertheless, they had a remarkably lower anti-SARS-CoV-2 neutralizing antibody titer compared with healthy controls. The T-cell response was measurable in 46% of patients with CVID (six of 13) at month 1 and persisted over the study period. Mild infection occurred in three patients within the follow-up period (14.3%). The vaccine also exhibited a favorable safety profile. CONCLUSIONS: The BNT162b2 vaccine elicited a measurable antibody response in a high proportion of patients, but it was limited by low titer of virus-neutralizing antibodies and rapid waning of anti-receptor-binding domain SARS-CoV-2-specific antibodies. T-cell response was detected in one-third of patients and remained stable within the follow-up period. Vaccination has favorable safety and clinical-related outcomes in preventing severe COVID-19.

Comparative study between virus neutralisation testing and other serological methods detecting anti-SARS-CoV-2 antibodies in Europe, 2021.

One consequence of the ongoing coronavirus disease pandemic was the rapid development of both in-house and commercial serological assays detecting anti-SARS-CoV-2 antibodies, in an effort to reliably detect acute and past SARS-CoV-2 infections. It is crucial to evaluate the quality of these serological tests and consequently the sero-epidemiological studies that are performed with the respective tests. Here, we describe the set-up and results of a comparative study, in which a laboratory contracted by the European Centre for Disease Prevention and Control offered a centralised service to EU/EEA Member and pre-accession Member States to test representative serum specimens with known serological results, with the gold standard technique (virus neutralisation tests) to determine the presence of neutralising antibodies. Laboratories from 12 European countries shared 719 serum specimens with the contractor laboratory. We found that in-house serological tests detecting neutralising antibodies showed the highest percent agreement, both positive and negative, with the virus neutralisation test results. Despite extensive differences in virus neutralisation protocols neutralisation titres showed a strong correlation. From the commercial assays, the best positive percent agreement was found for SARS-CoV-2 IgG (sCOVG) (Siemens - Atellica IM Analyzer). Despite lower positive percent agreement of LIAISON SARS-CoV-2 TrimericS IgG kit (Diasorin Inc.), the obtained results showed relatively good correlation with neutralisation titres. The set-up of this study allowed for high comparability between laboratories and enabled laboratories that do not have the capacity or capability to perform VNTs themselves. Given the variety of in-house protocols detecting SARS-CoV-2 specific neutralising antibodies, including the virus strain, it could be of interest to select reference isolates for SARS-CoV-2 diagnostic to be made available for interested EU Member States and pre-accession countries.

[Congenital rubella syndrome - case report]. / Vrozený zardenkový syndrom - kazuistika.

The goal of this case report is not only to describe a case of congenital rubella syndrome that is currently rarely seen in the Czech Republic but also to emphasize the importance of vaccination against rubella. Rubella usually occurs in susceptible children as a mild illness with rush. Its association with abortions and severe congenital disabilities was noticed in the 1940s. Since that time, efforts have been made to develop a vaccine against rubella to prevent congenital rubella syndrome.

Immunogenicity and safety of the booster BNT162b2 vaccine in patients with axial spondyloarthritis treated with biological disease-modifying drugs.

Background: Vaccination confers relatively short-term protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), indicating the need for booster doses. Immunocompromised individuals, including those with immune-mediated inflammatory diseases (IMIDs), may have pronounced immune response waning. Vaccine-boosted humoral and T-cell responses minimize poor coronavirus disease 19 (COVID-19) outcome without increasing adverse events (AE). There is limited evidence of third-dose vaccination in axial spondyloarthritis (AxSpA) patients. We investigated immune-response persistence after primary vaccination and immunogenicity and safety after the BNT162b2 booster vaccination. Methods: This prospective observational study enrolled an AxSpA cohort treated with interleukin-17 (IL-17) and tumor necrosis factor-alpha (TNFα) inhibitors. Serum SARS-CoV-2-specific and virus-neutralizing antibodies for humoral response and flow cytometric detection of intracellular cytokines following SARS-CoV-2-specific peptide-based stimulation for T-cell immune responses were assessed, and safety was evaluated via a clinical questionnaire. Results: Fifteen male AxSpA patients treated with TNFα (73·3%) or IL-17 (26·7%) inhibitors were enrolled and had humoral response persistence at 6 months: 905·6 ( ± 186·1 SD) and 409·1 ( ± 335·7) U/mL. Specific antibody concentrations further increased after booster vaccination to 989·7 ( ± 12·62) and 1000 U/mL and T-cell responders from 53·3% to 80%, with no differences between AxSpA (including "vaccination only" and "hybrid immunity" subgroups) and healthy control (HC) cohorts. No severe AE occurred; the AE spectrum was comparable to that of the general population. Conclusion: Immune-response persistence after primary vaccination and immunogenicity after booster vaccination were unaffected by anti-IL17 or anti-TNFα therapy with similar AE as in the general population.

SARS-CoV-2-specific humoral and cellular immune responses to BNT162b2 vaccine in Fibrodysplasia ossificans progressiva patients.

Introduction: Fibrodysplasia ossificans progressiva (FOP) is characterized by progressive heterotopic ossification triggered by various conditions, such as trauma, infection, including COVID-19 infection, and vaccination. Although SARS-CoV-2 vaccinations prevent poor outcomes in the general population, there is limited evidence on safety, immunogenicity, and efficacy of SARS-CoV-2 vaccines for inpatients with FOP. Methods: A case series of two patients with FOP focused on humoral, cellular post-vaccination response, and the incidence of adverse events after administration of the BNT162b2 vaccine (Comirnaty). Results: Injection site reactions, fever, myalgia, and fatigue were the most common adverse events (AE). Neither severe AE (SAE), nor disease flare-ups were observed. No differences between patients with FOP and healthy controls were observed in humoral and cellular responses. Conclusions: The BNT162b2 vaccine induced high humoral and cellular response levels in patients with FOP. Vaccination was not associated with SAE or disease relapse. The AEs spectrum was comparable to that of the general population.