No abstract

Along with efficacy and safety, it is extremely important to study the severity of humoral and cellular immunity during not only vaccination, but also revaccination against the Severe Acute Respiratory Syndromerelated CoronaVirus 2 (SARS-CoV-2).Aim. To compare the immunogenicity (humoral and cellular immunity) of various (heterologous and homologous) revaccination regimens against coronavirus disease 2019 (COVID-19) in a prospective observational study.Material and methods. In individuals aged ≥18 years, in the absence of contraindications to vaccination, two following types of vaccines were used for primary vaccination and revaccination: Gam-COVIDVac and CoviVac. Group I patients received Gam-COVID-Vac at each stage of primary and secondary vaccination; patients of group II — Gam-COVID-Vac at each stage of primary vaccination, CoviVac at each stage of re-vaccination; patients of group III — CoviVac at each stage of primary vaccination and Gam-COVID-Vac at each stage of revaccination; patients of group IV — CoviVac at each stage of primary and secondary vaccination. All participants (at each stage of vaccination, revaccination and 12 months after the primary vaccination) were determined the level of IgG to the receptor-binding domain of SARS-CoV-2 spike (S) protein and T-cell immunity to SARSCoV-2.Results. The maximum level of IgG at the second stage of revaccination was observed in groups I and III. In addition, in groups I, III and IV, a significant (p<0,0001) increase in IgG level by the second stage of revaccination was noted, the most pronounced in group III. In addition, there was a significantly (p<0,05) higher level of IgG at I and II stages of revaccination (Visit 3 and 4) among those vaccinated with Gam-COVID-Vac — 520 and 540 BAU/ml, respectively, compared with group IV vaccinated with CoviVac — 467 and 478 BAU/ml, respectively. The maximum and significant increase in active T-cells by the second stage of revaccination (Visit 4) was noted in groups I (p<0,0001) and III (p<0,0022) of vaccinated individuals, where it amounted to 11 and 12, respectively, which allows to consider the result positive (>8). At the same time, the level of active T cells responding to SARS-CoV-2 nucleocapsid Ag stimulation by Visit 4 (stage II of revaccination) was noted in groups II (14,5) and IV (12).Conclusion. The use of the Gam-COVID-Vac vaccine as a booster dose in both homologous and heterologous vaccination regimens against the SARS-CoV-2 virus is most effective for stimulation and humoral and T-cell post-vaccination response.

Difficulties in the differential diagnosis of non-ST-elevation myocardial infarction (NSTEMI) and acute myopericarditis during the novel coronavirus infection (COVID-19) pandemic appear to be a relevant and interesting issue.We present a clinical case of a 55-year-old female patient with an atypical presentation of NSTEMI. Initially, the disease resembles an acute viral infection. It was known that the patient came in contact with COVID-19 infection. Taking into account that the patient had dull left chest pain unrelated to physical activities, low-grade fever, elevated levels of troponin T and acute phase reactants, absence of  wall motion abnormalities, the  patient was assessed as having acute viral myopericarditis. Contrastenhanced cardiac magnetic resonance imaging (MRI) showed signs of myocardial infarction. Coronary angiography confirmed myocardial infarction and the patient underwent percutaneous coronary intervention (PCI). In the article we discuss the value of electrocardiography (ECG), echocardiography and MRI in the NSTEMI diagnosis, and also additional difficulties in the COVID-19 pandemic era. Due to high probability of myopericarditis the patient received non-steroidal anti-inflammatory drugs instead of optimal medical therapy and early PCI. Our clinical case demonstrates that despite of COVID-19 pandemic significant elevation of troponin level requires adherence to the acute myocardial infarction algorithm.