BACKGROUND: The longitudinal study was conducted over the initial 2 years of the COVID-19 pandemic, spanning from June 2020 to December 2022, in healthcare workers (HCWs) of the Thomayer University Hospital. A total of 3892 blood samples were collected and analyzed for total nucleocapsid (N) antibodies. The aim of the study was to evaluate the dynamics of N antibodies, their relationship to the PCR test, spike (S) antibodies, interferon-gamma, and prediction of reinfection with SARS-CoV-2. METHODS: Blood collections were performed in three rounds, along with questionnaires addressing clinical symptoms of past infection, PCR testing, and vaccination. Antibody measurements included total N antibodies (Roche Diagnostics) and postvaccination S antibodies (Euroimmun). Cellular immunity was tested by interferon-gamma release assay (Euroimmun). RESULTS: At the end of the study, 35.9% of HCWs were positive for N antibodies, and 39.5% of HCWs had either known PCR positivity or N antibodies or both. Ten percent of participants had no knowledge of a COVID-19 infection and 35% of positive individuals exhibited no symptoms. The values of positive antibodies decrease over a period of 6 months to 1 year, depending on the initial value, and their dynamics are highly variable. The study also demonstrated that the highest levels of spike antibodies and interferon-gamma occur during so-called hybrid immunity. CONCLUSION: Nucleocapsid antibodies proved valuable in monitoring SARS-CoV-2 infection dynamics, and they may detect cases of SARS-CoV-2 infection missed by PCR tests. The study identified distinct patterns in antibody dynamics and protection of hybrid immunity during reinfection.

• Klíčová slova
• COVID‐19, IGRA, SARS‐CoV‐2, hybrid immunity, nucleocapsid antibodies, serological marker, spike antibodies,
• MeSH
• biologické markery krev   MeSH
• COVID-19 * imunologie   krev   diagnóza   epidemiologie   MeSH
• dospělí MeSH
• fosfoproteiny MeSH
• glykoprotein S, koronavirus imunologie   MeSH
• interferon gama krev   MeSH
• koronavirové nukleokapsidové proteiny imunologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• longitudinální studie MeSH
• nemocnice univerzitní MeSH
• nukleokapsida imunologie   MeSH
• protilátky virové * krev   MeSH
• SARS-CoV-2 * imunologie   MeSH
• sérologické testování na COVID-19 metody   MeSH
• zdravotnický personál * statistika a číselné údaje   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biologické markery MeSH
• fosfoproteiny MeSH
• glykoprotein S, koronavirus MeSH
• interferon gama MeSH
• koronavirové nukleokapsidové proteiny MeSH
• nucleocapsid phosphoprotein, SARS-CoV-2 MeSH Prohlížeč
• protilátky virové * MeSH

In late 2023, several SARS-CoV-2 XBB descendants, notably EG.5.1, were predominant worldwide. However, a distinct SARS-CoV-2 lineage, the BA.2.86 variant, also emerged. BA.2.86 is phylogenetically distinct from other Omicron sublineages, accumulating over 30 amino acid mutations in its spike protein. Here, we examined the virological characteristics of the BA.2.86 variant. Our epidemic dynamics modeling suggested that the relative reproduction number of BA.2.86 is significantly higher than that of EG.5.1. Additionally, four clinically available antivirals were effective against BA.2.86. Although the fusogenicity of BA.2.86 spike is similar to that of the parental BA.2 spike, the intrinsic pathogenicity of BA.2.86 in hamsters was significantly lower than that of BA.2. Since the growth kinetics of BA.2.86 are significantly lower than those of BA.2 both in vitro and in vivo, the attenuated pathogenicity of BA.2.86 is likely due to its decreased replication capacity. These findings uncover the features of BA.2.86, providing insights for control and treatment.

• Klíčová slova
• BA.2.86, COVID-19, SARS-CoV-2, pathogenicity,
• MeSH
• aminokyseliny MeSH
• COVID-19 * MeSH
• kinetika MeSH
• křečci praví MeSH
• mutace MeSH
• SARS-CoV-2 genetika   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny MeSH

Shortly after the worldwide initiation of vaccination against SARS-CoV-2, concerns emerged about a possible link between vaccination, severe thrombocytopenia, and the development of atypical venous thrombosis. Concerns were primarily about AstraZeneca (ChAdOx1 nCov-19), later Johnson & Johnson (Ad26.COV2.S), but cases of acute immune thrombocytopenic purpura (ITP) and bleeding without thrombosis and also atypical venous thrombosis after exposure to the messenger RNA-based vaccines produced by Pfizer-BioNTech and Moderna have been reported. Examination of the circumstances of these complications revealed that this is a similar mechanism to heparin-induced thrombocytopenia (HIT), a prothrombotic thrombocytopenic hypercoagulable disorder with venous and arterial thrombosis. HIT is caused by platelet-activating IgG antibodies directed against an antigen that is a macromolecular complex consisting of platelet factor 4 (PF4) and heparin. Naming this new entity vaccine-induced immune thrombotic thrombocytopenia (VITT) was suggested to avoid confusion with HIT. Patients had high levels of antibodies to the immune complex formed by PF 4 and the polyanionic component of the vaccine (double-stranded DNA). In patients with thrombosis at any vascular site after vaccination, accompanied by absolute or relative thrombocytopenia and systemic manifestations, HIT Ig ELISA assay to detect antibodies against PF4 and platelet-activating functional tests may be used for VITT recognition and differentiation from venous thromboembolic disease. Immune globulin impedes antibody-mediated platelet clearance and down-regulate platelet activation by immune complexes, as in HIT. It is prudent to choose from among the nonheparin antithrombotic agents - direct oral F.Xa inhibitors, direct thrombin inhibitors and indirect F.Xa inhibitors for the treatment of thrombosis.

• Klíčová slova
• PF4 platelet activation functional test, PF4-ELISA HIT assay, atypical venous thrombosis, cerebral venous thrombosis, heparin-induced thrombocytopenia (HIT), platelet factor 4, portal venous thrombosis, vaccine-induced immune thrombotic thrombocytopenia (VITT),
• MeSH
• ChAdOx1 nCoV-19 MeSH
• COVID-19 * komplikace   MeSH
• idiopatická trombocytopenická purpura * etiologie   MeSH
• imunoglobulin G MeSH
• lidé MeSH
• SARS-CoV-2 MeSH
• trombocytopenie * chemicky indukované   diagnóza   MeSH
• trombocytový faktor 4 škodlivé účinky   MeSH
• trombóza * etiologie   MeSH
• vakcína Janssen proti COVID-19 MeSH
• vakcinace škodlivé účinky   MeSH
• vakcíny proti COVID-19 škodlivé účinky   MeSH
• vakcíny * škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ChAdOx1 nCoV-19 MeSH
• imunoglobulin G MeSH
• trombocytový faktor 4 MeSH
• vakcína Janssen proti COVID-19 MeSH
• vakcíny proti COVID-19 MeSH
• vakcíny * MeSH

In December 2019, a novel coronavirus (CoV) epidemic, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged from China. Coronaviruses belong to enveloped ssRNA viruses and are classified into four genera: Alpha coronavirus, Beta coronavirus, Gamma coronavirus and Delta coronavirus. It is assumed that SARS-CoV-2 is spread primarily during a personal contact via bigger respiratory droplets. These droplets with viruses can be directly inhaled by other people or can lend on the surfaces with the possibility of further spreading. The ocular surface has been suggested as one of possible infection entries. Human eye has its own renin-angiotensin system with present ACE2 receptors, which bind the virus through spike protein. The most common symptoms of the SARS-CoV-2 infection are fever, cough and dyspnoea. Several clinical entities, such as conjunctivitis, anterior uveitis, retinitis, and optic neuritis have been associated with this infection. The most common ophthalmologic symptom associated with COVID-19 disease is conjunctivitis. Some studies indicate that eye symptoms are commonly present in patients with severe COVID-19 pneumonia and that it is possible to detect viral RNA from the conjunctival sac of these patients. In ophthalmologic praxis, we manage not only the therapy of the eye structures` inflammation in relation with this infection, but also the overall management of the visits and the supervision of the patients who are at risk and positive for coronavirus. Ophthalmologists could potentially have a higher risk of SARS-CoV-2 infection due to personal communication with the patients, frequent exposure to tears and eye secrets and the use of devices. We would like to provide an ophthalmologist`s perspective on this topic.

• Klíčová slova
• ACE2, COVID-19, SARS-CoV-2, conjunctivitis, coronavirus, ocular surface,
• MeSH
• COVID-19 * MeSH
• lidé MeSH
• oftalmologové * MeSH
• pandemie MeSH
• SARS-CoV-2 MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Most studies investigating the characteristics of emerging SARS-CoV-2 variants have been focusing on mutations in the spike proteins that affect viral infectivity, fusogenicity, and pathogenicity. However, few studies have addressed how naturally occurring mutations in the non-spike regions of the SARS-CoV-2 genome impact virological properties. In this study, we proved that multiple SARS-CoV-2 Omicron BA.2 mutations, one in the spike protein and another downstream of the spike gene, orchestrally characterize this variant, shedding light on the importance of Omicron BA.2 mutations out of the spike protein.

• Klíčová slova
• BA.1, BA.2, COVID-19, Omicron, SARS-CoV-2, fusogenicity, growth capacity, immune resistance, pathogenicity,
• MeSH
• COVID-19 virologie   MeSH
• genom virový * genetika   MeSH
• glykoprotein S, koronavirus * genetika   MeSH
• lidé MeSH
• mutace * MeSH
• SARS-CoV-2 * genetika   patogenita   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• glykoprotein S, koronavirus * MeSH
• spike protein, SARS-CoV-2 MeSH Prohlížeč

By the end of 2019 the first cases of severe pneumonia of unknown origin were reported in Wuhan, China. The causative agent was identified as a novel b-coronavirus SARS-CoV-2 and the disease was named COVID-19. Since the beginning of 2020, the infection has spread worldwide, which led the WHO to declare COVID-19 a public health emergency of international concern and to characterize the current situation as a pandemic. The transmission occurs mainly via respiratory droplets and the incubation period ranges from 2 to 14 days. Most cases are mild, but some patients develop severe pneumonia with acute respiratory distress, septic shock and multi-organ failure. The most common symptoms include fever, dry cough, myalgia and shortness of breath. Characteristic laboratory findings are normal white blood cell count or mild leukopenia, marked lymphopenia, in severe cases elevated CRP, procalcitonin, LDH, and D-dimer are commonly found. Typical imaging findings include multifocal peripherally distributed ground-glass opacities or consolidations, interlobular septal thickening, crazy paving appearance and cystic changes. The overall case fatality rate is estimated to range from 1 to 3 %, however, it is dependent on age and underlying medical comorbidities. Current potential treatment options include hydroxychloroquine, remdesivir, lopinavir/ritonavir and convalescent plasma.

• Klíčová slova
• COVID-19, SARS-CoV-2, coronaviruses, pneumonia,
• MeSH
• Betacoronavirus * MeSH
• COVID-19 MeSH
• koronavirové infekce diagnóza   patofyziologie   MeSH
• lidé MeSH
• pandemie MeSH
• SARS-CoV-2 MeSH
• virová pneumonie diagnóza   patofyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Recovered COVID-19 patients may test positive for SARS-CoV-2 for a long time from intermittent shedding of viral fragments. A 36-year-old man who tested positive for SARS-CoV-2 in the Czech Republic and recovered tested positive again in Bhutan, 105 days beyond his first positive test. He experienced minimal symptoms and recovered without complications. Although no virological test was conducted to rule out reinfection, the repeat positive test after initial recovery likely resulted from prolonged shedding of dead viral particles than a reinfection.

• Klíčová slova
• Bhutan, COVID-19, Czech Republic, SARS-CoV-2,
• MeSH
• COVID-19 * MeSH
• dospělí MeSH
• lidé MeSH
• reinfekce MeSH
• SARS-CoV-2 * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH

BACKGROUND: The rapid diagnostics tests for SARS-CoV-2 antigen vary in their sensitivities, and moreover, genomic mutations may further affect the performance of the assays. We aimed to evaluate the analytical performance of an automated antigen assay and compare its sensitivity in Delta- and Omicron-variant positive clinical samples. MATERIAL AND METHODS: The analytical performance of an automated mariPOC SARS-CoV-2 antigen test was evaluated on a population of community-dwelling subjects with mild respiratory symptoms or being asymptomatic investigated by the RT-qPCR Allplex™ SARS-CoV-2 assay. The sensitivity and specificity of the antigen test were evaluated on prospective 621 nasopharyngeal swabs along with oropharyngeal swabs. The sensitivity regarding variants determined by the Allplex™ SARS-CoV-2 Variant assays was analysed in additional, retrospective 158 Delta and 59 Omicron samples. RESULTS: The overall sensitivity of the antigen test in prospective samples was 77.9% (113/145; 95% confidence interval [CI] 70.3-84.4) with the specificity of 99.8% (95% CI 98.8-100). Regarding the variant, the sensitivity was higher in Omicron-variant samples, 93.2% (55/59; 95% CI 83.5-98.1), compared to Delta-variant samples, 71.5% (113/158; 95% CI 63.8-78.4; p = .001). CONCLUSION: In community-dwelling subjects with mild respiratory symptoms or being asymptomatic, the automated mariPOC SARS-CoV-2 antigen test showed high sensitivity over 98.0% in subgroup samples with cycle threshold (Ct) values < 25. Regarding the variant, the antigen test sensitivity was higher in the Omicron-variant samples compared to the Delta-variant samples. The analytical performance of the antigen test can differ between the SARS-CoV-2 variants, and a re-evaluation should be performed for new circulating lineages.

• Klíčová slova
• Delta, Omicron, SARS-CoV-2, antigen testing, sensitivity,
• MeSH
• COVID-19 * diagnóza   MeSH
• lidé MeSH
• prospektivní studie MeSH
• retrospektivní studie MeSH
• SARS-CoV-2 * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Shortly after the WHOs first notice a suspected case of omicron SARS-CoV-2 was reported in Liberec, Czech Republic. The primary goal of the following actions was to test the presence of the variant and stop the spread of the virus variant. On November 25 a sixty-year-old lady, who had recently returned from Namibia, visited a GP with flu-like symptoms and a rash on her chest. The antigen test was positive for SARS-CoV-2, a PCR test was planned. At that time, it was not known that a new variant of concern was spreading from Africa. On November 26 in the morning the GP announced a suspected omicron case to the Regional public health authority, who organized the following steps. A mobile sampling team was sent to the patient's home immediately, sample transported into the regional hospital and analyzed with the help of the national reference laboratory. The captured virus SARS-CoV-2 fitted the description of the omicron variant, was shared in the GISAID database and named hCoV-19/Czech Republic/KNL_2021-110119140/2021. Contact tracing was started immediately, eleven persons were tested and quarantined. One of them positive with no further spread. It is the first documented omicron case in the Czech Republic and one of the first cases in Europe, with an excellent systemic response to the alert. The laboratory was able to detect the omicron variant instantly after the request. This case also demonstrates how easily the virus spreads on long distances and how important it might be to increase the uptake of the booster vaccine.

• Klíčová slova
• COVID-19, SARS-CoV-2, case report, omicron,
• MeSH
• COVID-19 * MeSH
• lidé středního věku MeSH
• lidé MeSH
• SARS-CoV-2 * MeSH
• výzkum MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Evropa MeSH

It has been a year since the first person on Earth became infected with a new type of coronavirus SARS-CoV-2, causing infectious acute respiratory disease COVID-19 with relatively high morbidity and mortality. The most endangered population by coronavirus SARS-CoV-2 are healthcare professionals, the elderly and people with associated comorbidities. Due to the fast community spread, governments of different European countries introduced precaution measures including limited socializing of people, closing of most public services and introducing mandatory facial protection. The hope for a return to the life before the pandemic is the development of an effective and safe vaccine against SARS-CoV-2 which would presumably reduce the incidence of severe forms of COVID-19 and prevent the massive spread of the disease. At the end of November, we have 13 clinical trials in phase III involving SARS-CoV-2 vaccines based on inactivated viruses, recombinant non-pathogenic viral vectors and proteins. The first mRNA-based vaccine is currently being evaluated in phase II/III clinical trial and is already being distributed and applied to high-risk population in the United Kingdom, the United States, and Israel, followed by the countries of the European Union, including the Czech Republic. In the review article we present currently ongoing clinical studies with a special focus on the phase III clinical trials and discuss the mechanisms of action of each type of vaccine.

• Klíčová slova
• COVID-19, SARS-CoV-2, Vaccines, clinical trials, type 2 diabetes,
• MeSH
• COVID-19 * MeSH
• lidé MeSH
• SARS-CoV-2 * MeSH
• senioři MeSH
• vakcinace MeSH
• vakcíny proti COVID-19 MeSH
• Check Tag
• lidé MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Geografické názvy
• Česká republika MeSH
• Evropa MeSH
• Spojené království MeSH
• Názvy látek
• vakcíny proti COVID-19 MeSH