Molnupiravir increases SARS-CoV-2 genome diversity and complexity: A case-control cohort study.

Molnupiravir, an oral direct-acting antiviral effective in vitro against SARS-CoV-2, has been largely employed during the COVID-19 pandemic, since December 2021. After marketing and widespread usage, a progressive increase in SARS-CoV-2 lineages characterized by a higher transition/transversion ratio, a characteristic signature of molnupiravir action, appeared in the Global Initiative on Sharing All Influenza Data (GISAID) and International Nucleotide Sequence Database Collaboration (INSDC) databases. Here, we assessed the drug effects by SARS-CoV-2 whole-genome sequencing on 38 molnupiravir-treated persistently positive COVID-19 outpatients tested before and after treatment. Seventeen tixagevimab/cilgavimab-treated outpatients served as controls. Mutational analyses confirmed that SARS-CoV-2 exhibits an increased transition/transversion ratio seven days after initiation of molnupiravir. Moreover we observed an increased G->A ratio compared to controls, which was not related to apolipoprotein B mRNAediting enzyme, catalytic polypeptide-like (APOBEC) activity. In addition, we demonstrated for the first time an increased diversity and complexity of the viral quasispecies.

Rapid Determination of SARS-CoV-2 Integrity and Infectivity by Using Propidium Monoazide Coupled with Digital Droplet PCR.

SARS-CoV-2 is a highly infectious virus responsible for the COVID-19 pandemic. Therefore, it is important to assess the risk of SARS-CoV-2 infection, especially in persistently positive patients. Rapid discrimination between infectious and non-infectious viruses aids in determining whether prevention, control, and treatment measures are necessary. For this purpose, a method was developed and utilized involving a pre-treatment with 50 µM of propidium monoazide (PMAxx, a DNA intercalant) combined with a digital droplet PCR (ddPCR). The ddPCR method was performed on 40 nasopharyngeal swabs (NPSs) both before and after treatment with PMAxx, revealing a reduction in the viral load at a mean of 0.9 Log copies/mL (SD ± 0.6 Log copies/mL). Furthermore, six samples were stratified based on the Ct values of SARS-CoV-2 RNA (Ct < 20, 20 < Ct < 30, Ct > 30) and analyzed to compare the results obtained via a ddPCR with viral isolation and a negative-chain PCR. Of the five samples found positive via a ddPCR after the PMAxx treatment, two of the samples showed the highest post-treatment SARS-CoV-2 loads. The virus was isolated in vitro from both samples and the negative strand chains were detected. In three NPS samples, SARS CoV-2 was present post-treatment at a low level; it was not isolated in vitro, and, when detected, the strand was negative. Our results indicate that the established method is useful for determining whether the SARS-CoV-2 within positive NPS samples is intact and capable of causing infection.

Viral load decrease in SARS-CoV-2 BA.1 and BA.2 Omicron sublineages infection after treatment with monoclonal antibodies and direct antiviral agents.

The efficacy on the Omicron variant of the approved early coronavirus disease-2019 (COVID-19) therapies, especially monoclonal antibodies, has been challenged by in vitro neutralization data, while data on in vivo antiviral activity are lacking. We assessed potential decrease from Day 1 to Day 7 viral load (VL) in nasopharyngeal swabs of outpatients receiving Sotrovimab, Molnupiravir, Remdesivir, or Nirmatrelvir/ritonavir for mild-to-moderate COVID-19 due to sublineages BA.1 or BA.2, and average treatment effect by weighted marginal linear regression models. A total of 521 patients (378 BA.1 [73%], 143 [27%] BA.2) received treatments (Sotrovimab 202, Molnupiravir 117, Nirmatrelvir/ritonavir 84, and Remdesivir 118): median age 66 years, 90% vaccinated, median time from symptoms onset 3 days. Day 1 mean VL was 4.12 log2 (4.16 for BA.1 and 4.01 for BA.2). The adjusted analysis showed that Nirmatrelvir/ritonavir significantly reduced VL compared to all the other drugs, except versus Molnupiravir in BA.2. Molnupiravir was superior to Remdesivir in both BA.1 and BA.2, and to Sotrovimab in BA.2. Sotrovimab had better activity than Remdesivir only against BA.1. Nirmatrelvir/ritonavir showed the greatest antiviral activity against Omicron variant, comparable to Molnupiravir only in the BA.2 subgroup. VL decrease could be a valuable surrogate of drug activity in the context of the high prevalence of vaccinated people and low probability of hospital admission.

Temporal intra-host variability of mpox virus genomes in multiple body tissues.

Whole-genome sequencing (WGS) has been widely used for the genomic characterization and the phylogenesis of mpox virus (MPXV) 2022 multi-country outbreak. To date, no evidence has been reported on intra-host evolution within samples collected over time from a single patient with long-term infection. Fifty-one samples were collected from five patients at different time points post-symptom onset. All samples were confirmed as MPXV DNA positive, amplified by a multiplexed PCR amplicon, and sequenced by WGS. Complete MPXV genomes were assembled by reference mapping and then aligned to perform phylogenetic and hierarchical clustering analysis. Large intra-host variability was observed among the MPXV genomes sequenced from samples of two immunocompromised with advanced HIV-1 infection patients with prolonged MPXV shedding. Overall, 20 nucleotide mutations were identified in the 32 genomes from HIV patients, differently distributed in samples collected from different tissues and at different time points. No sequence compartmentalization nor variation was observed in the three patients with rapid viral clearance. MPXV exhibits adaptation to changing environments within the infected host and consequently demonstrates tissue compartmentalization. Further studies are needed to elucidate the role of this adaptation in forming a pool of genetic variability and contributing to viral persistence and its clinical implications.

Effect of tecovirimat on healing time and viral clearance by emulation of a target trial in patients hospitalized for mpox.

Tecovirimat is a treatment option for severe mpox, although randomized clinical trials are ongoing. The aim of the study is to assess the effect of tecovirimat on healing time and the extent of viral clearance by target trial emulation using observational data. Clinical and virological data of patients hospitalized for mpox were collected. Samples from the upper respiratory tract (URT) were grouped in two time points: T1 (median 6 days from symptoms onset) and T2 (median 5 days from T1). Patients were followed-up until recovery. Average treatment effect (ATE) in patients untreated versus treated with tecovirimat was estimated on time to healing and variation in viral load in URT, using a weighted and cloning analysis. Among the 41 patients included, 19 completed a course of tecovirimat. The median time from symptoms onset to hospitalization and to drug-starting was 4 days and 10 days, respectively. No improvement in healing time in treated versus untreated was observed. No difference by treatment group in time to viral clearance was detected by ATE fitted in a subset of 13 patients after controlling for confounders. We found no evidence for a large effect of tecovirimat in shortening healing time and viral clearance. While awaiting the results of randomized studies, the use of tecovirimat should be restricted to the clinical trial setting.

Evolution of SARS-CoV-2 variants of concern over a period of Delta and Omicron cocirculation, among patients hospitalized for COVID-19 in an Italian reference hospital: Impact on clinical outcomes.

Despite the higher transmissibility of Omicron Variant of Concern (VOC), several reports have suggested lower risk for hospitalization and severe outcomes compared to previous variants of SARS-CoV-2. This study, enrolling all COVID-19 adults admitted to a reference hospital who underwent both the S-gene-target-failure test and VOC identification by Sanger sequencing, aimed to describe the evolving prevalence of Delta and Omicron variants and to compare the main in-hospital outcomes of severity, during a trimester (December 2021 to March 2022) of VOCs' cocirculation. Factors associated with clinical progression to noninvasive ventilation (NIV)/mechanical ventilation (MV)/death within 10 days and to MV/admission to intensive care unit (ICU)/death within 28 days, were investigated through multivariable logistic regressions. Overall, VOCs were: Delta n = 130/428, Omicron n = 298/428 (sublineages BA.1 n = 275 and BA.2 n = 23). Until mid-February, Delta predominance shifted to BA.1, which was gradually displaced by BA.2 until mid-March. Participants with Omicron VOC were more likely to be older, fully vaccinated, with multiple comorbidities and to have a shorter time from symptoms' onset, and less likely to have systemic symptoms and respiratory complications. Although the need of NIV within 10 days and MV within 28 days from hospitalization and the admission to ICU were less frequent for patients with Omicron compared to those with Delta infections, mortality was similar between the two VOCs. In the adjusted analysis, multiple comorbidities and a longer time from symptoms' onset predicted 10-day clinical progression, while complete vaccination halved the risk. Multimorbidity was the only risk factor associated with 28-day clinical progression. In our population, in the first trimester of 2022, Omicron rapidly displaced Delta in COVID-19 hospitalized adults. Clinical profile and presentation differed between the two VOCs and, although Omicron infections showed a less severe clinical picture, no substantial differences for clinical progression were found. This finding suggests that any hospitalization, especially in more vulnerable individuals, may be at risk for severe progression, which is more related to the underlying frailty of patients than to the intrinsic severity of the viral variant.

Outbreaks of autochthonous Dengue in Lazio region, Italy, August to September 2023: preliminary investigation.

Between August and September 2023, three distinct autochthonous dengue virus transmission events occurred in Lazio, Italy, with the main event in Rome. The events involved three different dengue serotypes. No link with previous imported cases was identified. Here we describe the epidemiological and phylogenetic analysis of the first autochthonous cases and the implemented control actions. The multiple transmission events call for a strengthening of the vector control strategies and future research to better characterise the risk in countries like Italy.

Infectious Toscana Virus in Seminal Fluid of Young Man Returning from Elba Island, Italy.

We report detecting infectious Toscana virus in the seminal fluid of a 25-year-old man from Italy returning from Elba Island. The presence of infectious virus in human semen adds Toscana virus to the long list of viruses detected in this genital fluid and indicates a potential for sexual transmission.

Unique human immune signature of Ebola virus disease in Guinea.

Despite the magnitude of the Ebola virus disease (EVD) outbreak in West Africa, there is still a fundamental lack of knowledge about the pathophysiology of EVD. In particular, very little is known about human immune responses to Ebola virus. Here we evaluate the physiology of the human T cell immune response in EVD patients at the time of admission to the Ebola Treatment Center in Guinea, and longitudinally until discharge or death. Through the use of multiparametric flow cytometry established by the European Mobile Laboratory in the field, we identify an immune signature that is unique in EVD fatalities. Fatal EVD was characterized by a high percentage of CD4(+) and CD8(+) T cells expressing the inhibitory molecules CTLA-4 and PD-1, which correlated with elevated inflammatory markers and high virus load. Conversely, surviving individuals showed significantly lower expression of CTLA-4 and PD-1 as well as lower inflammation, despite comparable overall T cell activation. Concomitant with virus clearance, survivors mounted a robust Ebola-virus-specific T cell response. Our findings suggest that dysregulation of the T cell response is a key component of EVD pathophysiology.

Epidemiological, clinical and virological characteristics of four cases of monkeypox support transmission through sexual contact, Italy, May 2022.

Since May 2022, an outbreak of monkeypox has been ongoing in non-endemic countries. We report four cases in Italy in young adult men reporting condomless sexual intercourse. The patients are in good clinical condition with no need for specific antiviral drugs. Biological samples from seminal fluid were positive for monkeypox viral DNA. For many other viruses found in semen there is no evidence of sexual transmission. The possibility of sexual transmission of monkeypox virus needs to be investigated.

External quality assessment of SARS-CoV-2 serology in European expert laboratories, April 2021.

BackgroundCountries worldwide are focusing to mitigate the ongoing SARS-CoV-2 pandemic by employing public health measures. Laboratories have a key role in the control of SARS-CoV-2 transmission. Serology for SARS-CoV-2 is of critical importance to support diagnosis, define the epidemiological framework and evaluate immune responses to natural infection and vaccine administration.AimThe aim of this study was the assessment of the actual capability among laboratories involved in sero-epidemiological studies on COVID-19 in EU/EEA and EU enlargement countries to detect SARS-CoV-2 antibodies through an external quality assessment (EQA) based on proficiency testing.MethodsThe EQA panels were composed of eight different, pooled human serum samples (all collected in 2020 before the vaccine roll-out), addressing sensitivity and specificity of detection. The panels and two EU human SARS-CoV-2 serological standards were sent to 56 laboratories in 30 countries.ResultsThe overall performance of laboratories within this EQA indicated a robust ability to establish past SARS-CoV-2 infections via detection of anti-SARS-CoV-2 antibodies, with 53 of 55 laboratories using at least one test that characterised all EQA samples correctly. IgM-specific test methods provided most incorrect sample characterisations (24/208), while test methods detecting total immunoglobulin (0/119) and neutralising antibodies (2/230) performed the best. The semiquantitative assays used by the EQA participants also showed a robust performance in relation to the standards.ConclusionOur EQA showed a high capability across European reference laboratories for reliable diagnostics for SARS-CoV-2 antibody responses. Serological tests that provide robust and reliable detection of anti-SARS-CoV-2 antibodies are available.

Temporal and spatial analysis of the 2014-2015 Ebola virus outbreak in West Africa.

West Africa is currently witnessing the most extensive Ebola virus (EBOV) outbreak so far recorded. Until now, there have been 27,013 reported cases and 11,134 deaths. The origin of the virus is thought to have been a zoonotic transmission from a bat to a two-year-old boy in December 2013 (ref. 2). From this index case the virus was spread by human-to-human contact throughout Guinea, Sierra Leone and Liberia. However, the origin of the particular virus in each country and time of transmission is not known and currently relies on epidemiological analysis, which may be unreliable owing to the difficulties of obtaining patient information. Here we trace the genetic evolution of EBOV in the current outbreak that has resulted in multiple lineages. Deep sequencing of 179 patient samples processed by the European Mobile Laboratory, the first diagnostics unit to be deployed to the epicentre of the outbreak in Guinea, reveals an epidemiological and evolutionary history of the epidemic from March 2014 to January 2015. Analysis of EBOV genome evolution has also benefited from a similar sequencing effort of patient samples from Sierra Leone. Our results confirm that the EBOV from Guinea moved into Sierra Leone, most likely in April or early May. The viruses of the Guinea/Sierra Leone lineage mixed around June/July 2014. Viral sequences covering August, September and October 2014 indicate that this lineage evolved independently within Guinea. These data can be used in conjunction with epidemiological information to test retrospectively the effectiveness of control measures, and provides an unprecedented window into the evolution of an ongoing viral haemorrhagic fever outbreak.

SARS-CoV-2 Phylogenetic Analysis, Lazio Region, Italy, February-March 2020.

We report phylogenetic and mutational analysis of severe acute respiratory syndrome coronavirus 2 virus strains from the Lazio region of Italy and provide information about the dynamics of virus spread. Data suggest effective containment of clade V strains, but subsequently, multiple waves of clade G strains were circulating widely in Europe.

Coronavirus disease (COVID-19) in a paucisymptomatic patient: epidemiological and clinical challenge in settings with limited community transmission, Italy, February 2020.

Data concerning the transmission of the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) in paucisymptomatic patients are lacking. We report an Italian paucisymptomatic case of coronavirus disease 2019 with multiple biological samples positive for SARS-CoV-2. This case was detected using the World Health Organization protocol on cases and contact investigation. Current discharge criteria and the impact of extra-pulmonary SARS-CoV-2 samples are discussed.

Specialist laboratory networks as preparedness and response tool - the Emerging Viral Diseases-Expert Laboratory Network and the Chikungunya outbreak, Thailand, 2019.

We illustrate the potential for specialist laboratory networks to be used as preparedness and response tool through rapid collection and sharing of data. Here, the Emerging Viral Diseases-Expert Laboratory Network (EVD-LabNet) and a laboratory assessment of chikungunya virus (CHIKV) in returning European travellers related to an ongoing outbreak in Thailand was used for this purpose. EVD-LabNet rapidly collected data on laboratory requests, diagnosed CHIKV imported cases and sequences generated, and shared among its members and with the European Centre for Disease Prevention and Control. Data across the network showed an increase in CHIKV imported cases during 1 October 2018-30 April 2019 vs the same period in 2018 (172 vs 50), particularly an increase in cases known to be related to travel to Thailand (72 vs 1). Moreover, EVD-LabNet showed that strains were imported from Thailand that cluster with strains of the ECSA-IOL E1 A226 variant emerging in Pakistan in 2016 and involved in the 2017 outbreaks in Italy. CHIKV diagnostic requests increased by 23.6% between the two periods. The impact of using EVD-LabNet or similar networks as preparedness and response tool could be improved by standardisation of the collection, quality and mining of data in routine laboratory management systems.

Expanding Usutu virus circulation in Italy: detection in the Lazio region, central Italy, 2017 to 2018.

Blood donation screening for West Nile virus (WNV) was mandatory in the Lazio region in 2017 and 2018 (June-November) according to the national surveillance plan. In these years, all five donations reactive in WNV nucleic acid amplification tests harboured instead Usutu virus (USUV). Clade 'Europe 2' was identified in four blood donations and a 2018 mosquito pool. The cocirculation of WNV and USUV in Lazio warrants increased laboratory support and awareness of possible virus misidentification.

Molecular Characterization of Autochthonous Chikungunya Cluster in Latium Region, Italy.

We report partial molecular characterization of isolates from an autochthonous chikungunya virus cluster in Latium Region. E1 sequences from 3 patients differ substantially from sequences from the 2007 outbreak in Italy and lack the A226V substitution associated with increased viral fitness in the Aedes albopictus mosquito vector.

Prolonged detection of dengue virus RNA in the semen of a man returning from Thailand to Italy, January 2018.

This study reports the presence of dengue virus RNA in longitudinally collected semen samples of a previously healthy Caucasian man, returning to Italy from Thailand with primary dengue fever, up to 37 days post-symptom onset, when viraemia and viruria were undetectable. This finding, coupled with the evidence of dengue virus negative-strand RNA, an indirect marker of ongoing viral replication, in the cellular fraction of semen, indicates a need to further investigate possible sexual transmission.

Persistence of ZIKV-RNA in the cellular fraction of semen is accompanied by a surrogate-marker of viral replication. Diagnostic implications for sexual transmission.

As asymptomatic infections represent 80% of ZIKV-infected individuals, sexual transmission is a rising concern. Recent studies highlighted a preferential association of ZIKV with the cellular fraction (CF) of different specimen types. Our aim was to evaluate the presence of ZIKV-RNA in different body fluids, focusing on semen specimens to assess the ZIKV-RNA content in either the unfractionated sample, its CF or seminal plasma (SP). In addition, to establish if the presence of ZIKV genome was associated with active virus replication, we measured the levels of negative-strand ZIKV-RNA. ZIKV total-RNA was detected in blood, urine and unfractionated semen, and neg-RNA in semen CF and SP samples longitudinally collected from two ZIKV-positive men followed at the National Institute for Infectious Diseases "L. Spallanzani", Italy. In both patients, ZIKV total-RNA was detected in CF with ct values always lower than in the corresponding unfractionated samples, and was observed even in the CF from negative unfractionated semen samples. In Patient 2, neg-RNA was also detected in CF, suggesting ongoing viral replication. Our results demonstrate higher clinical sensitivity of CF as compared to whole semen testing, emphasizing the need to extend ZIKV-RNA testing to CF, to rule out virus presence and the possible risk of sexual transmission.

Fatal Outbreak in Tonkean Macaques Caused by Possibly Novel Orthopoxvirus, Italy, January 2015 1.

In January 2015, during a 3-week period, 12 captive Tonkean macacques at a sanctuary in Italy died. An orthopoxvirus infection was suspected because of negative-staining electron microscopy results. The diagnosis was confirmed by histology, virus isolation, and molecular analysis performed on different organs from all animals. An epidemiologic investigation was unable to define the infection source in the surrounding area. Trapped rodents were negative by virologic testing, but specific IgG was detected in 27.27% of small rodents and 14.28% of rats. An attenuated live vaccine was administered to the susceptible monkey population, and no adverse reactions were observed; a detectable humoral immune response was induced in most of the vaccinated animals. We performed molecular characterization of the orthopoxvirus isolate by next-generation sequencing. According to the phylogenetic analysis of the 9 conserved genes, the virus could be part of a novel clade, lying between cowpox and ectromelia viruses.