Assessing the Intense Influenza A(H1N1)pdm09 Epidemic and Vaccine Effectiveness in the Post-COVID Season in the Russian Federation.

The COVID-19 pandemic had a profound impact on influenza activity worldwide. However, as the pandemic progressed, influenza activity resumed. Here, we describe the influenza epidemic of high intensity of the 2022-2023 season. The epidemic had an early start and peaked in week 51.2022. The extremely high intensity of the epidemic may have been due to a significant decrease in herd immunity. The results of PCR-testing of 220,067 clinical samples revealed that the influenza A(H1N1)pdm09 virus dominated, causing 56.4% of positive cases, while A(H3N2) influenza subtype accounted for only 0.6%, and influenza B of Victoria lineage-for 34.3%. The influenza vaccine was found to be highly effective, with an estimated effectiveness of 92.7% in preventing admission with laboratory-confirmed influenza severe acute respiratory illness (SARI) cases and 54.7% in preventing influenza-like illness/acute respiratory illness (ILI/ARI) cases due to antigenic matching of circulated viruses with influenza vaccine strains for the season. Full genome next-generation sequencing of 1723 influenza A(H1N1)pdm09 viruses showed that all of them fell within clade 6B.1A.5.a2; nine of them possessed H275Y substitution in the NA gene, a genetic marker of oseltamivir resistance. Influenza A(H3N2) viruses belonged to subclade 3C.2a1b.2a.2 with the genetic group 2b being dominant. All 433 influenza B viruses belonged to subclade V1A.3a.2 encoding HA1 substitutions A127T, P144L, and K203R, which could be further divided into two subgroups. None of the influenza A(H3N2) and B viruses sequenced had markers of resistance to NA inhibitors. Thus, despite the continuing circulation of Omicron descendant lineages, influenza activity has resumed in full force, raising concerns about the intensity of fore coming seasonal epidemics.

An Early SARS-CoV-2 Omicron Outbreak in a Dormitory in Saint Petersburg, Russia.

The Omicron variant of SARS-CoV-2 rapidly spread worldwide in late 2021-early 2022, displacing the previously prevalent Delta variant. Before 16 December 2021, community transmission had already been observed in tens of countries globally. However, in Russia, the majority of reported cases at that time had been sporadic and associated with travel. Here, we report an Omicron outbreak at a student dormitory in Saint Petersburg between 16-29 December 2021, which was the earliest known instance of a large-scale community transmission in Russia. Out of the 465 sampled residents of the dormitory, 180 (38.7%) tested PCR-positive. Among the 118 residents for whom the variant had been tested by whole-genome sequencing, 111 (94.1%) were found to carry the Omicron variant. Among these 111 residents, 60 (54.1%) were vaccinated or had reported a previous infection of COVID-19. Phylogenetic analysis confirmed that the outbreak was caused by a single introduction of the BA.1.1 sub-lineage of the Omicron variant. The dormitory-derived clade constituted a significant proportion of BA.1.1 samples in Saint Petersburg and has spread to other regions of Russia and even to other countries. The rapid spread of the Omicron variant in a population with preexisting immunity to previous variants underlines its propensity for immune evasion.

Electrocardiogram changes and wall motion abnormalities in the acute phase of Tako-Tsubo syndrome.

BACKGROUND: The Tako-Tsubo syndrome is still rarely diagnosed in patients presenting with symptoms of acute myocardial ischaemia. It is accompanied by wall motion abnormalities of the left ventricle but significant narrowings or occlusions of epicardial coronary arteries are absent. We investigated a potential relationship between electrocardiogram (ECG) changes, wall motion abnormalities and gender influence of Tako-Tsubo syndrome in an Austrian cohort of Tako-Tsubo syndrome patients. METHODS AND RESULTS: We were recently able to describe four different anatomical types of Tako-Tsubo syndrome in 153 patients of the Austrian Tako-Tsubo syndrome registry. In the present retrospective analysis we investigated ischaemia-related changes in the first diagnostic ECG for the different types of Tako-Tsubo syndrome: the apical and the combined apical-midventricular type showed most frequently a ST elevation (41.1% and 35.3%), whereas the midventricular type of Tako-Tsubo syndrome was more often accompanied by T wave inversion (60%). ECG changes in relation to the Tako-Tsubo syndrome type were similar in women and men. There was no difference in the prevalence of clinical complications among patients presenting with ST elevation or left bundle branch block (14.5%) compared with patients without ST elevation (10.4%) (p=0.476). CONCLUSION: Patients with Tako-Tsubo syndrome show characteristic ECG changes in the first diagnostic ECG which are associated to some extent with the anatomical type of Tako-Tsubo syndrome, but these ECG changes were not related to clinical outcome.

Stress-induced cardiomyopathy (Tako-Tsubo syndrome) in Austria.

BACKGROUND: Tako-Tsubo syndrome (TS) is a still rarely diagnosed clinical syndrome, which is characterized by acute onset of chest pain, transient cardiac dysfunction with (frequently) reversible wall motion abnormalities (WMAs), but with no relevant obstructive coronary artery disease. METHODS AND RESULTS: Among 179 consecutive patients with proven diagnosis of TS that were retrospectively analysed in this multicentre registry, women represented the majority of patients (94%) while only 11 men (6%) developed TS. Mean age was 69.1±11.5 years (range 35-88 years). Cardinal symptoms of TS, which led to admission, were acute chest pain (82%) and dyspnoea (32%), respectively. All patients demonstrated typical WMAs, whereby four different types of WMAs could be defined: (1) a more common apical type of TS (n=89; 50%); (2) a combined apical and midventricular form of TS (n=23; 13%); (3) the midventricular TS (n=6; 3%); and (4) an unusual type of basal WMAs of the left ventricle (n=3). Only in 101 patients (57%), a clear causative trigger for onset of symptoms could be identified. In-hospital cardiovascular complications occurred in 25 patients (14%) and consisted of cardiac arrhythmias in 10 patients (40%), cardiogenic shock in six patients (24%), cardiac decompensation in eight patients (32%) and cardiovascular death in one patient, respectively. Echocardiographic control of left ventricular function after the initial measurement was available in almost 70% of the patients: complete recovery of WMAs was found in 73 patients (58.87%); 49 patients (39.52%) showed persistent WMAs. Recurrences of TS were only seen in four patients. During the follow-up period, 13 patients died: three of cardiovascular causes and 10 of non-cardiac causes. In-hospital mortality was 0.6%, 30-day mortality was 1.3% and 2-year mortality was 6.7%. CONCLUSIONS: This study represents to date the largest series of patients suffering from TS in Austria and worldwide. Similar to others, in our series the prevalence of TS was significantly higher in women than in men, while in contrast to other studies, the apical type of TS was detected most frequently. The similar clinical presentation of TS patients to the clinical picture of acute myocardial infarction demonstrates the importance of immediate coronary angiography for adequate differential diagnosis of TS. TS is not necessarily a benign disease due to cardiovascular complications as well as persistent WMAs with delayed recovery.