Low prevalence of influenza viruses and predominance of A(H3N2) virus with respect to SARS-CoV-2 during the 2021-2022 season in Bulgaria.

Social distancing, mask-wearing, and travel restrictions during the COVID-19 pandemic have significantly impacted the spread of influenza viruses. The objectives of this study were to analyze the pattern of influenza virus circulation with respect to that of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Bulgaria during the 2021-2022 season and to perform a phylogenetic/molecular analysis of the hemagglutinin (HA) and neuraminidase (NA) sequences of representative influenza strains. Influenza infection was confirmed using real-time reverse transcription polymerase chain reaction in 93 (4.2%) of the 2193 patients with acute respiratory illness tested wherein all detected viruses were subtyped as A(H3N2). SARS-CoV-2 was identified in 377 (24.3%) of the 1552 patients tested. Significant differences in the incidence of influenza viruses and SARS-CoV-2 were found between individual age groups, outpatients/inpatients, and in the seasonal distribution of cases. Two cases of coinfections were identified. In hospitalized patients, the Ct values of influenza viruses at admission were lower in adults aged ≥65 years (indicating higher viral load) than in children aged 0-14 years (p < 0.05). In SARS-CoV-2-positive inpatients, this association was not statistically significant. HA genes of all A(H3N2) viruses analyzed belonged to subclade 3C.2a1b.2a. The sequenced viruses carried 11 substitutions in HA and 5 in NA, in comparison to the vaccine virus A/Cambodia/e0826360/2020, including several substitutions in the HA antigenic sites B and C. This study revealed extensive changes in the typical epidemiology of influenza infection, including a dramatic reduction in the number of cases, diminished genetic diversity of circulating viruses, changes in age, and seasonal distribution of cases.

Chest CT diagnostic potential as a tool for early detection of suspected COVID-19 cases in pandemic peaks.

INTRODUCTION: The emergence of severe acute respiratory syndrome coronavirus disease (COVID-19) in China at the end of 2019 caused a massive global outbreak that has become a major public health issue. AIM: Our aim was to investigate the diagnostic potential of chest CT in screening patients suspected of having COVID-19 in high-prevalence settings. MATERIALS AND METHODS: This is a real-life, prospective, observational study involving 260 patients. All patients received chest CT scan at the emergency department (ED) of Kaspela University Hospital, Plovdiv, Bulgaria and RT-PCR testing for suspected COVID-19 from March 27 to December 31, 2020. COVID-19 likelihood was assessed by assigning each CT scan to a particular category of the COVID-19 Reporting and Data System (CO-RADS). IBM SPSS v. 26 was used to process the data. RESULTS: The male-to-female distribution ratio was 1.4:1 - 150 (57.7%) males vs. 110 (42.3%) females (p=0.014). The median age was 55 yrs (range 46-65 yrs). Discharged patients were 247 (95.0%), the rest died in the COVID-19 intensive care unit. Males were 4.13 times more likely to be diagnosed with CO-RADS≥3 score than females. Increasing age was associated with an increased likelihood of being classified with higher CO-RADS scores. The ROC curves analysis demonstrated that CO-RADS ≥3 was the optimal cutoff for discrimi-nating between a positive and negative PCR (Youden's index J=0.67), with an AUC of 0.825 (95% CI 0.72-0.93), sensitivity of 91.9% (95% CI 87.7%-95.1%), specificity of 75.0% (95% CI 53.3%-90.2%) and accuracy of 76.4% (95% CI 70.7%-81.4%). CONCLUSIONS: The results of this study reveal that a CT examination can provide a quick and accurate diagnosis of patients with sus-pected COVID-19 infection, whereas the PCR test is time-consuming, and the delay in receiving results can be substantial when the incidence curve begins to grow rapidly.

Renin-angiotensin-aldosterone system blockers in Bulgarian COVID-19 patients with or without chronic kidney disease.

When angiotensin-converting enzyme inhibitor/angiotensin receptor blocker-treated patients present with SARS-CoV-2 infection there is a debate to know whether renin-angiotensin-aldosterone (RAAS) blockers should be stopped or not. We conducted a prospective observational study in Bulgarian COVID-19-infected patients with or without chronic kidney disease (CKD) to assess whether maintenance RAAS blocker therapy has an impact on SARS-CoV-2 infection and its complications. We included 120 in-patient COVID-19 subjects, of whom 70 had CKD and 50 had normal renal function. A total of 30% of the patients (total number of 36 patients, 21 females) were receiving RAAS therapy at admission and it was maintained throughout hospitalization. The overall mortality was 19.2% (23 patients); there was no significant difference across the 2 groups (P-value = .21), except in RAAS blockers-treated hypertensive patients who had a significantly lower mortality as compared to non-RAAS-blockers-treated hypertensive patients (P = .04). Regarding subsequent intensive-care unit admission, there were 50% less patients in the RAAS group (4 out of 36, i.e., 11%) as compared to 19 out of 84 from the non-RAAS group, that is, 22.6% (P = .29). Overall, 37 patients developed acute kidney injury (any stage by KDIGO); of them 14 (37.8%) were receiving RAAS blockers. Acute kidney injury was not significantly associated with the use of RAAS blockers (P-value = .28). Likewise, both in non-CKD and in CKD patients the use of RAAS blockers did not have an impact on renal function recovery after SARS-CoV-2 infection. Finally, regarding RAAS blockers and the biological parameters outcome only D-dimers were significantly lower at the follow-up as compared to that in non-RAAS blocker treated patients. RAAS blockers benefited patients with hypertension by lowering mortality rate. Other than that, RAAS blocker therapy continuation during SARS-CoV-2 infection in CKD and non-CKD patients had no significant impact upon major outcomes.

SARS-CoV-2 reinfections during the first three major COVID-19 waves in Bulgaria.

BACKGROUND: The COVID-19 pandemic has had a devastating impact on the world over the past two years (2020-2021). One of the key questions about its future trajectory is the protection from subsequent infections and disease conferred by a previous infection, as the SARS-CoV-2 virus belongs to the coronaviruses, a group of viruses the members of which are known for their ability to reinfect convalescent individuals. Bulgaria, with high rates of previous infections combined with low vaccination rates and an elderly population, presents a somewhat unique context to study this question. METHODS: We use detailed governmental data on registered COVID-19 cases to evaluate the incidence and outcomes of COVID-19 reinfections in Bulgaria in the period between March 2020 and early December 2021. RESULTS: For the period analyzed, a total of 4,106 cases of individuals infected more than once were observed, including 31 cases of three infections and one of four infections. The number of reinfections increased dramatically during the Delta variant-driven wave of the pandemic towards the end of 2021. We observe a moderate reduction of severe outcomes (hospitalization and death) in reinfections relative to primary infections, and a more substantial reduction of severe outcomes in breakthrough infections in vaccinated individuals. CONCLUSIONS: In the available datasets from Bulgaria, prior infection appears to provide some protection from severe outcomes, but to a lower degree than the reduction in severity of breakthrough infections in the vaccinated compared to primary infections in the unvaccinated.

Students' Attitudes toward COVID-19 Vaccination: An Inter-University Study from Bulgaria.

In Bulgaria, vaccination coverage against the SARS-CoV-2 virus is low. The reasons for this fact are many and varied. The aim of the present study was to establish what the attitudes towards the COVID-19 vaccination process are among students from various specialties from several Bulgarian universities. In this research, 600 students participated, divided into two groups: Doctor of Medicine (MD) students (n = 300) and non-MD students, i.e., students of specialties, such as mathematics, engineering, finance and economics, law, human sciences, etc. (n = 300). Each respondent completed a questionnaire which was divided into three parts with closed questions. The mean age of all students was 21.19 ± 1.87 years (95% CI: 20.48-21.90). The female sex dominated among the analyzed participants (sex ratio: female/male = 1/0.85). Nearly 62% (371/600) of individuals declared that they have been COVID-19 vaccinated with at least one dose (p < 0.001). Overall, 33% of the participants sought information on vaccines from video sharing platforms and 36.0% (216/600) from social media platforms. From the conducted multivariable logistic regression the odds of vaccination against COVID-19 were 6.225 times higher in individuals with a positive attitude towards these vaccines than in people with a negative attitude towards them (p < 0.001). We have found that those students who trust the international health organizations had an OR of 2.365 (p = 0.004) to be SARS-CoV-2 vaccinated. We estimated that the odds of vaccination against SARS-CoV-2 among children were 4.794 times higher in parents (students) who had been vaccinated than in non-vaccinated parents (students) (p < 0.001). Our results could support the national public health organizations, the national educational/scientific systems, and the management of Bulgarian universities in making future decisions about the field of COVID-19 control and prevention.

Initial introduction and spread of the SARS-CoV-2 AY.4.2.1 Delta variant in Bulgaria, a genomic insight.

The evolution of the emerging SARS-CoV-2 variants carrying mutations in the spike protein raises concerns about the possibility of accelerated transmission in the ever-evolving COVID-19 pandemic worldwide. AY.4.2, a sublineage of the Delta variant, was considered a variant under investigation (VUI) and also gained the nickname "Delta Plus," due to its extra mutations, Y145H and A222V. In this study, using genomic epidemiology, we provide the first insights into the introduction of AY.4.2 in Bulgaria and the AY.4.2.1 sublineage that found larger dissemination only in Bulgaria and the United Kingdom.

The demographic and geographic impact of the COVID pandemic in Bulgaria and Eastern Europe in 2020.

The COVID-19 pandemic followed a unique trajectory in Eastern Europe compared to other heavily affected regions, with most countries there only experiencing a major surge of cases and deaths towards the end of 2020 after a relatively uneventful first half of the year. However, the consequences of that surge have not received as much attention as the situation in Western countries. Bulgaria, even though it has been one of the most heavily affected countries, has been one of those neglected cases. We use mortality and mobility data from Eurostat, official governmental and other sources to examine the development and impact of the COVID-19 pandemic in Bulgaria and other European countries. We find a very high level of excess mortality in Eastern European countries measured by several metrics including excess mortality rate (EMR), P-scores, potential years of life lost (PYLL) and its age standardised version (ASYR), and working years of life lost (WYLL). By the last three metrics Eastern Europe emerges as the hardest hit region by the pandemic in Europe in 2020. With a record EMR at ~0.27% and a strikingly large and mostly unique to it mortality rate in the working age (15-64 years) demographics, Bulgaria emerges as one of the most affected countries in Eastern Europe. The high excess mortality in Bulgaria correlates with insufficient intensity of testing, with delayed imposition of "lockdown" measures, and with high prevalence of cardiovascular diseases. We also find major geographic and demographic disparities within the country, with considerably lower mortality observed in major cities relative to more remote areas (likely due to disparities in the availability of medical resources). Analysis of the course of the epidemic revealed that individual mobility measures were predictive of the eventual decline in cases and deaths. However, while mobility declined as a result of the imposition of a lockdown, it already trended downwards before such measures were introduced, which resulted in a reduction of deaths independent of the effect of restrictions. Large excess mortality and high numbers of potential years of life lost are observed as a result of the COVID pandemic in Bulgaria, as well as in several other countries in Eastern Europe. Significant delays in the imposition of stringent mobility-reducing measures combined with a lack of medical resources likely caused a substantial loss of life, including in the working age population.

A comparison of health system responses to COVID-19 in Bulgaria, Croatia and Romania in 2020.

This article compares the health system responses to COVID-19 in Bulgaria, Croatia and Romania from February 2020 until the end of 2020. It explores similarities and differences between the three countries, building primarily on the methodology and content compiled in the COVID-19 Health System Response Monitor (HSRM). We find that all three countries entered the COVID-19 crisis with common problems, including workforce shortages and underdeveloped and underutilized preventive and primary care. The countries reacted swiftly to the first wave of the COVID-19 pandemic, declaring a state of emergency in March 2020 and setting up new governance mechanisms. The initial response benefited from a centralized approach and high levels of public trust but proved to be only a short-term solution. Over time, governance became dominated by political and economic considerations, communication to the public became contradictory, and levels of public trust declined dramatically. The three countries created additional bed capacity for the treatment of COVID-19 patients in the first wave, but a greater challenge was to ensure a sufficient supply of qualified health workers. New digital and remote tools for the provision of non-COVID-19 health services were introduced or used more widely, with an increase in telephone or online consultations and a simplification of administrative procedures. However, the provision and uptake of non-COVID-19 health services was still affected negatively by the pandemic. Overall, the COVID-19 pandemic has exposed pre-existing health system and governance challenges in the three countries, leading to a large number of preventable deaths.

Increased prevalence of gastrointestinal symptoms and disorders of gut-brain interaction during the COVID-19 pandemic: An internet-based survey.

BACKGROUND: Quarantine with social distancing has reduced transmission of COVID-19; however, fear of the disease and these remedial measures cause anxiety and stress. It is not known whether these events have impacted the prevalence of gastrointestinal (GI) symptoms and disorders of brain-gut interaction (DGBI). METHODS: An online platform evaluated the prevalence of GI symptoms during the COVID-19 pandemic. Data collection utilized validated questionnaires and was fully anonymized. Findings were compared with identical data acquired in 2019. The association of results with stress and anxiety was analyzed. RESULTS: Data were collected from 1896 subjects May - August 2019 to 980 non-identical subjects May - June 2020. GI symptoms were reported by 68.9% during the COVID-19 lockdown compared with 56.0% the previous year (p < 0.001). The prevalence of irritable bowel syndrome (26.3% vs. 20.0%; p < 0.001), functional dyspepsia (18.3% vs. 12.7%; p < 0.001), heartburn (31.7% vs. 26.2%, p = 0.002), and self-reported milk intolerance (43.5% vs. 37.8% p = 0.004) was higher during the pandemic. Many individuals reported multiple symptoms. Anxiety was associated with presence of all GI symptoms. High levels of stress impacted functional dyspepsia (p = 0.045) and abdominal pain (p = 0.013). The presence of DGBI (p < 0.001; OR 22.99), self-reported milk intolerance (p < 0.001; OR 2.50), and anxiety (p < 0.001; OR 2.18) was independently associated with increased GI symptoms during COVID-19 pandemic. CONCLUSIONS: The prevalence of GI symptoms was significantly higher during the COVID-19 lockdown than under normal circumstances the previous year. This increase was attributable to increased numbers of patients with DGBI, an effect that was associated with anxiety.

Clinical Characteristics of Hospitalized Patients with COVID-19 in Sofia, Bulgaria.

Introduction: SARS-CoV-2 infection is spreading around the world, including countries from Southeastern Europe. The purpose of the study was to present the clinical manifestations of COVID-19 patients admitted to the Military Medical Academy, Sofia, Bulgaria. Materials and Methods: A retrospective study was conducted for a period of 3 months from March 2020 to June 2020 on this infection in our hospital. All participants were laboratory confirmed cases of COVID-19. RT-PCR was performed for etiological diagnosis. The hospitalized patients were divided into two groups on admission, that is, nonsevere and severe. Results: One hundred thirty-eight COVID-19 patients were hospitalized and analyzed during the study period. The mean age was 52.9 years. Male was the dominant sex (sex ratio: male/female = 1/0.6). The leading clinical signs were fever, fatigue, cough, and headache. On comparative analysis of both groups (nonsevere and severe) was measured significant elevation of white blood cells (odds ratio [OR] = 1.238; p value = 0.006), C-reactive protein (OR = 1.021; p < 0.001), creatinine (OR = 1.037; p < 0.001), aspartate aminotransferase (OR = 1.014; p = 0.040), lactate dehydrogenase (OR = 1.004; p < 0.001), ferritin (OR = 1.002; p < 0.001), fibrinogen (OR = 2.028; p < 0.001), and d-dimer (OR = 2.162; p = 0.002) in severe group than in nonsevere group. Interleukin 6 was tested in 17.4% of patients and high value was found-38.6 pg/mL (95% confidence interval: 16.5-60.7). Conclusion: The first Bulgarian retrospective study of COVID-19 hospitalized patients was presented. Older age, male sex, comorbidity, and signs of dyspnea and nausea were estimated as higher risk factors for severe form. Abnormality in inflammatory markers was associated with poor progression of the illness.