COVID-19 infection elicits textbook immune response.

Imunita po prodelané infekci SARS-CoV-2 byla dlouhodobe zpochybnována. Z jiných typu respiracních onemocnení vsak víme, ze bunky, které se vytvorí pri první infekci, dlouhodobe prezívají a pri opakované infekci je díky nim imunitní reakce rychlejsí a úcinnejsí. Popisuje se zvýsení hladin protilátek, jejich lepsí avidita a vznik nových variant. Jiz existující pametové B a T lymfocyty jsou pouzity jako "prototyp", který se dále vylepsuje. U reinfikovaných osob tak logicky klesá riziko vázných prubehu onemocnení. V predkládaném clánku jsou uvedeny výsledky dlouhodobého merení hladiny IgG protilátek proti proteinum S a N a IgA protilátek proti proteinu S u 4 osob, které prodelaly opakované infekce SARS-CoV-2 spojené s nárustem hladin protilátek a s méne závazným prubehem, nez mela primoinfekce. Tyto zkusenosti potvrzují i závery z nasí predchozí dlouhodobé studie imunity u senioru z roku 2020, v níz byla také pozorována reaktivace imunity u rekonvalescentu po pravdepodobné nové expozici SARS-CoV-2, ale bez prodelaného onemocnení. Prezentované výsledky potvrzují jiz dríve publikovaná fakta, tedy ze prodelání nemoci neposkytuje dlouhodobou ochranu pred reinfekcí, zvláste novou variantou viru, ale pokud jiz k reinfekci dojde, bývá její prubeh méne závazný nez pri primoinfekci.

COVID-19 in 96 Patients With Hematologic Disease: The First Single-center Experience From the Czech Republic.

BACKGROUND: Coronavirus disease 2019 (COVID-19) represents an important infectious complication associated with high mortality rates in patients with hematologic diseases. There have not been published any epidemiologic studies from Czech Republic so far. PATIENTS AND METHODS: This study is the first analysis of patients with hematologic malignancies and bone marrow failure syndromes treated at single hematology center in the Czech Republic between March 1 and December 31, 2020, in whom COVID-19 infection was confirmed. RESULTS: The sample comprised 96 patients aged 26 to 84 years (median, 66.0 years). At the time of their COVID-19 diagnosis, 75 patients (78.1%) were treated for hematologic diseases. Twenty-seven patients (28.1%) in the sample had complete remission (CR) of their hematologic disease. They were nonsignificantly more likely to have asymptomatic to moderate COVID-19 infection than those who failed to achieve CR (74.1% vs. 56.5%; P = .06). A more severe course of the infection was significantly correlated with older age (P = .047). Lung involvement was also statistically significantly associated with older age (P = .045). Over the study period, a total of 15 patients died. Age greater than 60 years was significantly associated with deaths from COVID-19 (P = .036), with failure to achieve CR having a statistically nonsignificant impact on mortality (P = .22). CONCLUSION: These results confirm the prognostic significance of age for achieving treatment response of hematologic disease as well as the severity and mortality of COVID-19 in hematology patients.

Five Commercial Immunoassays for SARS-CoV-2 Antibody Determination and Their Comparison and Correlation with the Virus Neutralization Test.

There is an ongoing debate as to whether SARS-CoV-2 antibodies can be found in patients who have recovered from COVID-19 disease. Currently, there is no consensus on whether the antibodies, if present, are protective. Our regular measurements of SARS-CoV-2 antibodies, starting in July 2020, have provided us with the opportunity of becoming acquainted with the five different immunoassays. A total of 149 patients were enrolled in our study. We measured the samples using each immunoassay, then performing a virus neutralization test and comparing the results of SARS-CoV-2 antibodies with this test. We observed that the production of neutralizing antibodies is age-dependent. Elderly patients have a higher proportion of high neutralizing titers than young patients. Based on our results, and in combination with the literature findings, we can conclude that the serological SARS-CoV-2 antibody measurement is a helpful tool in the fight against COVID-19. The assays can provide information about the patient's previous contact with the virus. Anti-spike protein assays correlate well with the virus neutralization test and can be used in the screening of potential convalescent plasma donors.

Exploratory drilling: how to set up, carry out, and evaluate a seroprevalence study.

Seroprevalence studies represent a very important tool to find out what fraction of population has already met with the new type of coronavirus (e.g. SARS-CoV-2). Without these data, it is almost impossible for the state authorities to manage the epidemic and adopt rational measures. This article brings the results of a medium-sized seroprevalence study which was carried out in the spring of 2020 in South Bohemia. In the Strakonice and Písek regions, the ELISA method was used to test the prevalence of IgA and IgG antibodies in 2011 subjects, volunteers from general public and selected professions working in areas with a higher exposure to the infection. The study showed that already in May 2020, 2.9% of inhabitants of the Strakonice region and 1.9% of inhabitants of the Písek region had antibodies against the coronavirus. These numbers imply that for each PCR positive person, there were at least fifty others who had probably already undergone the infection. The article points out three types of problems that might occur in such a study. First, the study must be planned correctly, and possible outcomes must be pre-assessed. Second, an appropriate test must be selected with known parameters. This enables us to correctly estimate the share of false positive and false negative results. Third, the data must be evaluated in a reasonable way and correct inference must be performed. We offer a set of recommendations how to manage these issues and how to solve problems that inevitably arise in such a large-scale testing.