Ovidiu Vlaicu

Introduction: A broad range of common respiratory viruses contributes substantially to the burden of acute respiratory infections (ARIs) across all age groups. However, data on their epidemiology, seasonality, and clinical impact in Eastern Europe remain limited. Methods: We conducted a retrospective laboratory-based surveillance study including patients evaluated for ARIs at the National Institute for Infectious Diseases “Prof. Dr. Matei Balș”, Bucharest, Romania, between November 2022 and October 2025. Respiratory samples were tested using multiplex real-time RT-PCR panels detecting multiple respiratory viruses. The present analysis focused on adenovirus (AdV), enterovirus (HEV), rhinovirus (HRV), parainfluenza virus (PIV), human coronaviruses (CoV), human bocavirus (HBoV), and human metapneumovirus (MPV). Epidemiological characteristics, detection patterns, and clinical outcomes were analyzed. Results: Among 4930 patients tested, 1709 (34.7%) had at least one of the studied viruses detected, corresponding to 2144 viral detections (22.2% patients with viral codetections). HRV was the most frequently detected virus. Also, viral codetections most commonly involved HRV. Analysis of monthly detections across the three seasons studied demonstrated virus-specific temporal patterns. Specifically, MPV demonstrated a more consistent winter–spring detection pattern, whereas HRV was detected throughout the study period. Overall, 50.2% of patients required hospitalization, with the highest rates observed among patients with CoVs and MPV detection. Requirement of supplemental oxygen was more common in patients hospitalized with MPV (28.4%) and PIV (24.6%). Patients with viral codetections had higher hospitalization rates compared with those with monodetections (57.7% vs. 48.1%; OR = 1.47; p < 0.001), although no significant differences were observed in requirement of supplemental oxygen, ICU admission, or length of hospital stay. Conclusions: AdV, HEV, MPV, PIV, HBoV, CoV and HRV accounted for a substantial proportion of viral detections among patients evaluated for ARIs in routine clinical practice. The predominance of HRV and the frequent occurrence of viral codetections highlight the complexity of respiratory viral epidemiology revealed by multiplex molecular diagnostics. Broader surveillance of respiratory viruses may improve understanding of respiratory infection dynamics in the post-pandemic period.

Mpox has become a significant health concern since the global outbreak that began in 2022. The aim of this study is to present the epidemiological situation of Mpox in Romania during 2022–2023 and to describe a severe case of Mpox in a patient who survived despite multiple co-pathologies. Forty-seven confirmed cases were reported at the national level, all in men, in 2022. The median age was 33 years. Twenty-six cases involved men who have sex with men (MSM), and twenty-three tested positive for HIV. We also describe a severe case involving a 34-year-old bisexual male with newly diagnosed AIDS who developed severe Mpox with persistent necrotic skin lesions, respiratory involvement, and multiple opportunistic infections: tuberculosis, pneumocystis pneumonia, syphilis, and oral candidiasis. The patient presented with fever, night sweats, weight loss, and dyspnea, with a single ulcerative facial lesion that later disseminated. Mpox infection was confirmed through PCR from skin lesion, serum, saliva, urine, rectal, nasal, and pharyngeal swab samples, with high viral loads persisting despite prolonged Tecovirimat therapy. The patient developed immune reconstitution inflammatory syndrome following the initiation of antiretroviral therapy. This case emphasizes the challenges of treating Mpox in immunocompromised patients.

Influenza viruses continue to be an important public health threat. Vaccination is the most effective measure to control the influenza virus circulation. However, these viruses are continuously evolving through antigenic drift/shift, and thus the vaccine efficiency is affected. The aim of this study was to characterize the viral strains circulating in Romania, in a population with declining vaccination coverage, during the last three cold seasons by evaluating the hemagglutinin antigenic relatedness to the vaccine strains. All the available sequences collected between August 2021 and June 2024 were analyzed by using phylogenetic analysis and the P_epitope model to predict vaccine efficacy. The results showed that the 2021/2022 influenza season was dominated by the circulation of highly diverse clades of A(H3N2) viruses with high mutational divergence as compared to the vaccine strain, which might contribute to the reduction in vaccine efficacy. During the 2022/2023 influenza season, both influenza A and B viruses were reported, with few antigenic site mutations. The 2023/2024 influenza season was dominated by the circulation of influenza A viruses: A/H1N1pdm09 clade 6B.1A.5a.2a and A/H3N2 clade 2a.3a.1. The clade 2a.3a.1 also showed high variability when compared to the vaccine strain, presumably leading to reduced vaccine efficacy. This study illustrates the high diversity of influenza viruses circulating in a population with low vaccination coverage during the previous cold seasons. The viral diversity impacted vaccine efficacy, hence the need for public health programs to increase vaccine uptake and improve vaccine formulation in order to limit viral transmission.

Emerging SARS-CoV-2 strains continue to generate difficulties for authorities and health care professionals worldwide due to enhanced transmissibility and/or immune response evasion. The appearance of the Alpha and Delta strains has been associated with substantial increases in the number of COVID-19 cases and associated deaths. Whole Genome Sequencing (WGS) continues to be the gold standard for molecular surveillance of the pandemics but other assays such as mutation genotyping can be used to reduce costs and allocated time. This study investigates the efficiency of mutation screening tests compared to WGS and their predictive value to anticipate future waves. A very high degree of fidelity for this type of assay was found, regardless of the method used. The positive predictive value (PPV) of 4/5 markers was over 95% for the detection of Alpha and Delta variants. By estimating the prevalence of the Alpha and Delta strains using genotyping assays and fitting the data to a mathematical model, a five week period between the point of exponential growth of variant prevalence and a drastic increase in case numbers was found. For that reason, raising awareness about the efficacy of mutation screening could help authorities adopt better measures in the future.

New SARS-CoV-2 variants are constantly emerging and putting a strain on public health systems by spreading faster and potentially evading immune protection through vaccination. One of these strains is the B.1.1.7 variant that has initially been described in the UK and has subsequently spread to several countries. Monitoring the amplification of the S gene – a major hotspot for molecular evolution – by RT-PCR allows rapidly screening for such variants. This report describes the detection of sequence variants in Romania by using this strategy followed by next generation sequencing of the entire genome for confirmation and further characterization. One B.1.1.7 and three B.1.258 sequences where confirmed. Each of these strains presented additional mutations with possible impact on the replicative capacity. Conclusion: public health strategies should be devised in order to ensure molecular monitoring of SARS-CoV-2 evolution during the pandemic and allow adequate and rapid reaction.

BACKGROUND: The spread of SARS-CoV-2 generated an unprecedented global public health crisis. Soon after Asia, Europe was seriously affected. Many countries, including Romania, adopted lockdown measures to limit the outbreak. AIM: We performed a molecular epidemiology analysis of SARS-CoV-2 viral strains circulating in Romania during the first two months of the epidemic in order to detect mutation profiles and phylogenetic relatedness. METHODS: Respiratory samples were directly used for shotgun sequencing. RESULTS: All Romanian sequences belonged to lineage B, with a different subtype distribution between northern and southern regions (subtype B.1.5 and B.1.1). Phylogenetic analysis suggested that the Romanian epidemic started with multiple introduction events from other European countries followed by local transmission. Phylogenetic links between northern Romania and Spain, Austria, Scotland and Russia were observed, as well as between southern Romania and Switzerland, Italy, France and Turkey. One viral strain presented a previously unreported mutation in the Nsp2 gene, namely K489E. Epidemiologically-defined clusters displayed specific mutations, suggesting molecular signatures for strains coming from areas that were isolated during the lockdown. CONCLUSIONS: Romanian epidemic was initiated by multiple introductions from European countries followed by local transmissions. Different subtype distribution between northern and southern Romania was observed after two months of the pandemic.

O1 HIV-1 diversity in Bulgaria (current molecular epidemiological picture) Ivailo Alexiev, Reneta Dimitrova, Anna Gancheva, Asya Kostadinova, Mariyana Stoycheva, Daniela Nikolova, Ivaylo Elenkov O2 Knowledge, attitudes and practices of the general population on HIV/AIDS, hepatitis B and C in Romania Cătălin Tilișcan, Mioara Predescu, Bogdan Păunescu, Anca Streinu-Cercel, Oana Săndulescu, Claudiu Mihai Șchiopu, Mădălina Hristache, Lăcrămioara Aurelia Brîndușe, Adrian Streinu-Cercel O3 The prevalence of human leukocyte antigen-B*57:01 allele carriers and CXCR4 tropism among newly diagnosed HIV infected patients in Serbia Marija Todorovic, Marina Siljic, Dubravka Salemovic, Valentina Nikolic, Ivana Pesic-Pavlovic, Jovan Ranin, Djordje Jevtovic, Maja Stanojevic O4 HIV transmission among stable serodiscordant couples from the former Pediatric Cohort follow up in the National Institute of Infectious Diseases Ana Maria Tudor, Delia Vlad, Mariana Mărdărescu, Sorin Petrea, Cristina Petre, Ruxandra Neagu-Drăghicenoiu, Rodica Ungurianu, Alina Cibea, Odette Chirilă, Cristian Anghelina, Ileana Coserea O5 Unemployment is associated with syringe sharing among people who inject drugs in Greece Pantelia-Amalia Krikelli, Eirini Pavlitina, Mina Psichogiou, Demetris Lamnisos, Leslie Williams, Anya Korobchuk, Britt Skaathun, Pavlo Smyrnov, John Schneider, Vana Sypsa, Dimitrios Paraskevis, Angelos Hatzakis, Samuel R. Friedman, Georgios K. Nikolopoulos O6 Correlation of adipocytokine levels in different types of lipodystrophy in HIV/AIDS patients Gordana Dragović, Danica Srdić, Al Musalhi Khawla, Ivan Soldatović, Jelena Nikolić, Djordje Jevtović, Devaki Nair O7 IP10 – a possible biomarker for the progression of HIV infection Aura Temereanca, Adelina Rosca, Luminita Ene, Benchawa Soontornniyomkij, Carmen Diaconu, Claudia Dita, Cristian Achim, Simona Ruta O8 A permanent challenge: persistent low viremia in HIV positive patients on ART Șerban Benea, Ruxandra Moroti, Raluca Jipa, Eliza Manea, Andrada Stan, Elisabeta Benea, Dan Oțelea, Adriana Hristea O9 Infections in IDUs according to their HIV status Adriana Hristea, Irina Lăpădat, Raluca Jipa, Ruxandra Moroti, Șerban Benea, Doina Antonică, Irina Panait, Roxana Petre O10 Trends in combined antiretroviral therapy used in methadone program integrated with HIV care - 20 years of experience Justyna D. Kowalska, Ewa Pietraszkiewicz, Ewa Grycner, Ewa Firlag-Burkacka, Andrzej Horban O11 Extracellular cyclophilin A – inflammatory mediator in HIV infected patients Ovidiu Vlaicu, Leontina Bănică, Simona Paraschiv, Ana-Maria Tudor, Ruxandra Moroti, Dan Oțelea O12 High cardiovascular disease risk in Serbian population, an issue of concern Bojana Dimitrijević, Ivan Soldatović, Đorđe Jevtović, Jovana Kusić, Dubravka Salemović, Jovan Ranin, Gordana Dragović O13 Genotypic rifampicin resistance in HIV/ tuberculosis coinfected patients from a tertiary level infectious diseases hospital Dragoș Florea, Ioana Bădicuț, Alexandru Rafila, Cornel Camburu, Adriana Histrea, Mihaela Frățilă, Dan Oțelea O14 Occurrence of residual HCV RNA in liver and peripheral blood mononuclear cells among patients with chronic hepatitis C infection and/or HCV/HIV coinfection after IFN-based therapy Ivana Gmizic, Dubravka Salemovic, Ivana Pesic-Pavlovic, Marina Siljic, Valentina Nikolic, Miljana Djonin-Nenezic, Ivana Milosevic, Branko Brmbolic, Maja Stanojevic O15 Romanian nationwide screening for infection with HIV and hepatitis B and C viruses Anca Streinu-Cercel, Oana Săndulescu, Alina Cristina Neguț, Mioara Predescu, Alexandra Mărdărescu, Mihai Săndulescu, Adrian Streinu-Cercel O16 Treatment emergent variants to combined direct antiviral agents therapy against hepatitis C virus Ana Belen Pérez, Natalia Chueca, Marta Álvarez, Juan Carlos Alados, Antonio Rivero, Francisco Vera, Marcial Delgado, Javier Salmeron, Miguel Jiménez, Maria José Blanco, Moises Diago, Miguel Garcia-deltoro, Marta Alvarez, Francisco Téllez, Federico García O17 Clinical and epidemiological aspects in tuberculosis/HIV coinfected patients Diana Tănase, Eliza Manea, Rodica Bacruban, Dragoș Florea, Dan Oțelea, Alexandru Rafila, Mariana Mărdărescu, Adriana Hristea O18 Resistance to NS3 protease inhibitors in persons with chronic hepatitis C infected with hepatitis C virus subtype 1a from Croatia Ivana Grgic, Ana Planinic, Maja Santak, Lana Gorenec, Snjezana Zidovec Lepej, Adriana Vince O19 Analysis of a simplified diagnostic score for tuberculous meningitis in HIV-infected adults with meningitis Eliza Manea, Adriana Hristea, Șerban Benea, Ruxandra Moroti, Diana Tănase, Cristian M. Niculae, Simona Merisor, Raluca Jipa O20 Molecular tracing of the origin of HIV-1 infection among persons who inject drugs in Athens: a phyloethnic study Dimitrios Paraskevis, Evangelia Kostaki, Georgios K. Nikolopoulos, Vana Sypsa, Mina Psichogiou, Dimitra Paraskeva, Athanassios Skoutelis, Meni Malliori, Samuel R. Friedman, Angelos Hatzakis O21 The dynamics of virological response to HIV-1 infection and antiretroviral therapy initiation in patients with and without HLA-B*5701 Allele Malgorzata Hackiewicz, Piotr Zabek, Ewa Firlag-Burkacka, Andrzej Horban, Justyna Dominika Kowalska O22 Increase in the numbers of non-B subtypes and potential recombinant forms circulating among Slovenian MSM in the recent years Maja M. Lunar, Jana Mlakar, Mario Poljak O23 Genotyping intrahost polymorphisms in hepatitis C virus E2 protein associated with resistance to antibody neutralization Leontina Bănică, Eliza Martin, Valeriu Gheorghiță, Andrei Petrescu, Dan Oțelea, Costin-Ioan Popescu, Simona Paraschiv O24 Genotyping of HCV...

Hepatitis C Virus (HCV) infects over 150 million people worldwide. In most cases HCV infection becomes chronic, causing liver disease ranging from fibrosis to cirrhosis and hepatocellular carcinoma. HCV affects the cholesterol homeostasis and at the molecular level, every step of the virus life cycle is intimately connected to lipid metabolism. In this review, we present an update on the lipids and apolipoproteins that are involved in the HCV infectious cycle steps: entry, replication and assembly. Moreover, the result of the assembly process is a lipoviroparticle, which represents a peculiarity of hepatitis C virion. This review illustrates an example of an intricate virus-host interaction governed by lipid metabolism.