Resurgence of respiratory syncytial virus with dominance of RSV-B during the 2022-2023 season.

Background: Respiratory syncytial virus (RSV) is a common cause of upper and lower respiratory tract infections. This study aimed to explore the prevalence of respiratory syncytial virus (RSV) and other respiratory viruses in Bulgaria, characterize the genetic diversity of RSV strains, and perform amino acid sequence analyses of RSV surface and internal proteins. Methods: Clinical and epidemiological data and nasopharyngeal swabs were prospectively collected from patients with acute respiratory infections between October 2020 and May 2023. Real-time PCR for 13 respiratory viruses, whole-genome sequencing, phylogenetic, and amino acid analyses were performed. Results: This study included three epidemic seasons (2020-2021, 2021-2022, and 2022-2023) from week 40 of the previous year to week 20 of the following year. Of the 3,047 patients examined, 1,813 (59.5%) tested positive for at least one viral respiratory pathogen. RSV was the second most detected virus (10.9%) after SARS-CoV-2 (22%). Coinfections between RSV and other respiratory viruses were detected in 68 cases, including 14 with SARS-CoV-2. After two seasons of low circulation, RSV activity increased significantly during the 2022-2023 season. The detection rates of RSV were 3.2, 6.6, and 13.7% in the first, second, and third seasons, respectively. RSV was the most common virus found in children under 5 years old with bronchiolitis (40%) and pneumonia (24.5%). RSV-B drove the 2022-2023 epidemic. Phylogenetic analysis indicated that the sequenced RSV-B strains belonged to the GB5.0.5a and GB5.0.6a genotypes. Amino acid substitutions in the surface and internal proteins, including the F protein antigenic sites were identified compared to the BA prototype strain. Conclusion: This study revealed a strong resurgence of RSV in the autumn of 2022 after the lifting of anti-COVID-19 measures, the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, and relatively low genetic diversity in circulating RSV strains.

Impact of vaccination on the presence and severity of symptoms in hospitalized patients with an infection of the Omicron variant (B.1.1.529) of the SARS-CoV-2 (subvariant BA.1).

OBJECTIVES: The emergence of SARS-CoV-2 variants raised questions about the extent to which vaccines designed in 2020 have remained effective. We aimed to assess whether vaccine status was associated with the severity of Omicron SARS-CoV-2 infection in hospitalized patients. METHODS: We conducted an international, multi-centric, retrospective study in 14 centres (Bulgaria, Croatia, France, and Turkey). We collected data on patients hospitalized for ≥24 hours between 1 December 2021 and 3 March 2022 with PCR-confirmed infection at a time of exclusive Omicron circulation and hospitalization related or not related to the infection. Patients who had received prophylaxis by monoclonal antibodies were excluded. Patients were considered fully vaccinated if they had received at least two injections of either mRNA and/or ChAdOx1-S or one injection of Ad26.CoV2-S vaccines. RESULTS: Among 1215 patients (median age, 73.0 years; interquartile range, 57.0-84.0; 51.3% men), 746 (61.4%) were fully vaccinated. In multivariate analysis, being vaccinated was associated with lower 28-day mortality (Odds Ratio [95% Confidence Interval] (OR [95CI]) = 0.50 [0.32-0.77]), intensive care unit admission (OR [95CI] = 0.40 [0.26-0.62]), and oxygen requirement (OR [95CI] = 0.34 [0.25-0.46]), independent of age and comorbidities. When co-analysing these patients with Omicron infection with 948 patients with Delta infection from a study we recently conducted, Omicron infection was associated with lower 28-day mortality (OR [95CI] = 0.53 [0.37-0.76]), intensive care unit admission (OR [95CI] = 0.19 [0.12-0.28]), and oxygen requirements (OR [95CI] = 0.50 [0.38-0.67]), independent of age, comorbidities, and vaccination status. DISCUSSION: Originally designed vaccines have remained effective on the severity of Omicron SARS-CoV-2 infection. Omicron is associated with a lower risk of severe forms, independent of vaccination and patient characteristics.

Recurrent meningitis caused by Salmonella enterica Paratyphi B var. Java in a 3-month-old infant complicated by dilation of subarachnoid spaces, subdural effusion and right-sided hemiparesis.

A 3-month-old female infant with meningo-encephalitis caused by Salmonella enterica Paratyphi B var. Java is described. The aetiological agent was confirmed in six CSF samples; however, none of the blood or faecal samples was positive for the same pathogen. The presence of the bacteria was confirmed in the CSF by culture, serology and Multiplex PCR assay. The infant developed dilated subarachnoid spaces and right-sided hemiparesis associated with the persistent bacterial meningo-encephalitis. She was re-admitted 2 weeks after recovery and initial discharge from hospital owing to recurrence of S. enterica Paratyphi B bacteria in the CSF and the development of large bilateral subdural effusions in the brain. Computed tomography and the clinical course confirmed dynamically progressive meningo-encephalitis. Following further parenteral antibiotics and symptomatic treatment, the child's condition improved. After a total of 24 days in the PICU, she was sufficiently improved to be discharged with a residual right-sided hemiparesis. However, sadly she died a week after discharge.Abbreviation: ALT: alanine aminotransferase; API: analytical profile index 20 E-test; AST: aspartate aminotransferase; CRP: C-reactive protein; CSF: cerebrospinal fluid; CT: computed tomography; EUCAST: European Committee on Antimicrobial Susceptibility Testing; MDCT: multi-detector computed tomography; PCR: polymerase chain reaction; PICU: paediatric intensive care unit; RBC: red blood cells; VITEK: automated instrument for identification/antimicrobial susceptibility testing; WBC: white blood cells.

Acute severe hepatitis outbreak in children: A perfect storm. What do we know, and what questions remain?

During the first half of 2022, the World Health Organization reported an outbreak of acute severe hepatitis of unknown aetiology (AS-Hep-UA) in children, following initial alerts from the United Kingdom (UK) where a cluster of cases was first observed in previously well children aged <6 years. Sporadic cases were then reported across Europe and worldwide, although in most countries incidence did not increase above the expected baseline. There were no consistent epidemiological links between cases, and microbiological investigations ruled out known infectious causes of hepatitis. In this review, we explore the evidence for the role of viral infection, superimposed on a specific host genetic background, as a trigger for liver pathology. This hypothesis is based on a high prevalence of Human Adenovirus (HAdV) 41F in affected children, together with metagenomic evidence of adeno-associated virus (Adeno-associated viruses)-2, which is a putative trigger for an immune-mediated liver injury. Roles for superantigen-mediated pathology have also been explored, with a focus on the potential contribution of SARS-CoV-2 infection. Affected children also had a high frequency of the MHC allele HLA-DRB1*04:01, supporting an immunological predisposition, and may have been vulnerable to viral coinfections due to disruption in normal patterns of exposure and immunity as a result of population lockdowns during the COVID-19 pandemic. We discuss areas of ongoing uncertainty, and highlight the need for ongoing scrutiny to inform clinical and public health interventions for this outbreak and for others that may evolve in future.

Future developments in training.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has demonstrated the value of highly skilled and extensively trained specialists in clinical microbiology (CM) and infectious diseases (ID). Training curricula in CM and ID must constantly evolve to prepare trainees for future pandemics and to allow trainees to reach their full clinical and academic potential. OBJECTIVES: In this narrative review, we aim to outline necessary future adaptations in CM and ID training curricula and identify current structural barriers in training with the aim of discussing possibilities to address these shortcomings. SOURCES: We reviewed literature from PubMed and included selected books and online publications as appropriate. There was no time constraint on the included publications. CONTENT: Drawing from the lessons learnt during the pandemic, we summarize novel digital technologies relevant to CM and ID trainees and highlight interdisciplinary teamwork and networking skills as important competencies. We centre CM and ID training within the One Health framework and discuss gender inequalities and structural racism as barriers in both CM and ID training and patient care. IMPLICATIONS: CM and ID trainees should receive training and support developing skills in novel digital technologies, leadership, interdisciplinary teamwork and networking. Equally important is the need for equity of opportunity, with firm commitments to end gender inequality and structural racism in CM and ID. Policy-makers and CM and ID societies should ensure that trainees are better equipped to achieve their professional goals and are better prepared for the challenges awaiting in their fields.

COVID-19 and gastrointestinal injury: a brief systematic review and data from Bulgaria.

In December 2019, a new Coronavirus (SARS-CoV-2) emerged in China, causing the pandemic disease COVID-19. The clinical presentation is variable, but the predominant symptoms are those of the upper respiratory tract. AIM: The aim of the current study is to describe the incidence and type of the gastrointestinal injury (GI) in COVID-19, as well as their prognostic value. MATERIALS AND METHODS: We conducted a coincidental search on this topic in PubMed, Web of Science and EMBASE. We also followed a group of 31 Bulgarian COVID-19 patients throughout the course of their disease and analyzed their symptoms (catarrhal and other) and outcome. RESULTS: The publications concerning our survey followed a total of 1509 COVID-19 patients. In the Bulgarian cohort, only 14 from the 31 patients were laboratory-confirmed COVID-19 cases. Approximately 1/3 of the infected individuals presented with GI. In some patients this was the first, or only, symptom of the disease. It was also indicative of a more severe disease course. CONCLUSION: GI may be an important symptom and prognostic factor in COVID-19. Therefore, patients with acute gastrointestinal symptoms must be actively tested for SARS-CoV-2.