Background: There is much data available concerning the initiation of the immune response after SARS-CoV-2 infection, but long-term data are scarce. Methods: We thus longitudinally evaluated and compared the total and neutralizing immune response of 61 patients to SARS-CoV-2 infection up to eight months after diagnosis by RT–PCR using several commercial assays. Results: Among the 208 samples tested, the percentage of seropositivity was comparable between assays up to four months after diagnosis and then tended to be more heterogeneous between assays (p < 0.05). The percentage of patients with a neutralizing titer decreased from 82% before two months postdiagnosis to 57% after six months. This decrease appeared to be more marked for patients under 65 years old and those not requiring hospitalization. The percentage of serology reversion at 6 months was from 11% with the WANTAI total assay to over 39% with the ABBOTT IgG assay. The neutralizing antibody titers decreased in parallel with the decrease of total antibody titers, with important heterogeneity between assays. Conclusions: In conclusion, serological tests show equivalent sensitivity in the first months after the diagnosis of SARS-CoV-2 infection, but their performance later, postinfection, must be considered when interpreting the results.

Epstein–Barr virus (EBV) is one of the most prevalent human viruses worldwide. The COVID-19 pandemic, with its social distancing measures, has disrupted the circulation of many viruses. Delayed EBV primary infection is known to increase the risk of secondary conditions, including infectious mononucleosis, multiple sclerosis, and Hodgkin’s lymphoma. In this context, we aimed to investigate whether EBV seroprevalence has been affected over time, particularly in relation to the COVID-19 period, by analyzing all patients admitted to Amiens University Hospital from January 2013 to December 2023 who underwent EBV serology. During this period, 19,771 EBV serologies were performed and analyzed. The total seropositive rate of EBV infections approached 90%, considering all non-negative serological profiles, with the rate stabilizing after 2017. The number of EBV serologies increased significantly until 2016, as well as the age of the screened patients. Less than 3% of patients remain seronegative after 25 years, indicating a seroprevalence of around 97%. The overall primary infection rate was 2.6%. There was no significant difference in the number of primary infections in 2020–2021, the years associated with confinements and curfews in France in the context of the COVID-19 pandemic, compared with the other years. The overall EBV seroprevalence and age of primary infection remained stable during the study period, suggesting a moderate impact of the COVID-19 pandemic on seroprevalence in this cohort.

Background/Objectives: In the absence of an effective antiviral treatment for BK polyomavirus (BKPyV), a better understanding of the epidemiology and time course of BKPyV replication after kidney transplantation is needed to limit the virus’s impact on the graft outcome. Methods: In a 7-year study, we screened more than 430 kidney transplant recipients and analyzed the time course and virological characteristics of BKPyV replication. Results: Urinary viral replication was observed in 116 (27%) of the 430 patients, and 90 of the 116 (78%) had viral DNAemia. Thirty-eight patients (8.8%) were presumed to have nephropathy (DNAemia > 4 log10 copies/mL). Of the patients with BKPyV replication, 48%, 60%, 71%, and 80% were first found to be positive one, two, three, and four months post-transplantation. The initial viral load in the urine was below 7 log10 copies/mL in 100% of the patients with viral replication first detected before the first month, and this proportion was 57% when viral replication was first detected after the first month. When the BKPyV replication was first detected in a urine sample at month 3 or later, 81.5% of patients had concomitant BKPyV DNAemia. The predominant viral subtype was Ib2 (60%), and there was no apparent relationship between the subtype and the time course of BKPyV replication. Conclusions: Urinary BKPyV replication occurs early after renal transplantation and in most patients will increase to a level requiring therapeutic intervention. Close monitoring for BKPyV in the early post-transplantation period would enable the pre-emptive adjustment of the immunosuppression regimen.

A link between idiopathic male infertility and viral infections exhibiting seminal carriage has emerged recently. In this respect, human papillomavirus (HP

Background: The modes of transmission of BK polyomavirus (BKPyV) remain incompletely understood. BKPyV infections can lead to hemorrhagic cystitis after hematopoietic stem cell transplantation (HSCT). Hospitalization in a pediatric hematology unit may represent initial exposure to BKPyV due to the high rate of viral shedding among hematology patients. This study explores the potential for nosocomial transmission of BKPyV within a hematology department. Methods: Epidemiologic investigation and BKPyV genome phylogenetic analyses were conducted among individuals with BKPyV DNAuria and/or DNAemia over a 3-year period in a pediatric hematology unit. Results: From November 2019 to December 2022, BKPyV DNA was detected in the urine or plasma of 34 of 173 children following HSCT. An unusually high prevalence of genotype Ia BKPyV was observed in 2021, suggesting possible patient-to-patient transmission. However, despite closely related sequences, they clustered with several GenBank entries, complicating phylogenetic linkage determination. Genetic signature analysis also did not link these sequences to specific patient clinical profiles. Discussion: This study highlights the complexity of establishing nosocomial transmission of BKPyV, even with viral sequence analyses. Future prospective studies should include noncoding control region analysis, serological data, and environmental factors to enhance understanding of BKPyV transmission routes.