In 2024, an early and rapid rise in enterovirus D68 (EV-D68) infections in France prompted the implementation of enhanced nationwide surveillance to characterize the outbreak. EV-D68 screening was performed as part of the routine hospital strategy of the 2 national reference laboratories and of the national surveillance of enterovirus infections. Of 919 patients, 49.1% (451/919) were adults. Severe infection was reported in 169 patients (102 children and 67 adults). We observed neurologic complications in 7 children (seizures and encephalitis) and 4 adults (myelitis). Infections peaked in week 38 and were associated with subgenotypes A2 and B3; A2 predominated, particularly in adults (317/457 [69.3%] A2 infections). Complete genome analyses identified a new A2-derived lineage with mutations clustering in exposed regions of viral capsid protein 1. Our findings highlight the substantial clinical impact of EV-D68 in adults as well as children, underscoring the need for broad clinical and genomic surveillance.

ABSTRACT Enteroviruses (EVs) are the most frequent cause of pediatric aseptic meningitis, and cause neurological complications, such as encephalitis and flaccid paralysis. Our aim was to characterize the age-specific cytokine and chemokine response profiles in the cerebrospinal fluid (CSF) and blood of neonates, infants, and children with enterovirus meningitis. We performed an ancillary study to the French multicenter BLEDI study. We selected 163 patients with confirmed EV or suspected meningitis. Demographic, clinical, and laboratory data were analyzed. Twenty-seven cytokine/chemokines were simultaneously quantified in the CSF and plasma of the patients, using a bio-plex multiplex immunoassay. Cytokine-chemokine expression increased in the CSF with the age of EV patients compared with controls: CSF IP-10, IL-6, and IL-1ra increased 13-, 11-, 5-fold, respectively, in neonates, 41-, 53-, and 20-fold in infants, and 52-, 168-, and 69-fold in children. In plasma, cytokine/chemokines were overexpressed in neonates and downregulated in children, compared with their respective controls: plasma MCP-1, IP-10, and IL-1ra increased 10-fold in neonates, and decreased threefold in children. The expression of cytokine/chemokines varied with CSF pleocytosis but not with EV types and viral load. These findings show that cytokine and chemokine responses during EV meningitis are strongly age-dependent and should be interpreted according to patient age, with neonates, infants, and children being considered separately. Our results also indicate that age stratification is essential in future studies aiming to evaluate cytokines and chemokines as biomarkers of disease severity in EV-associated neurological infections.IMPORTANCEAlthough enteroviruses (EVs) are the main cause of pediatric viral meningitis, the age-specific immune response to infection remains poorly understood. Our work is novel in combining the study of paired biological compartments (cerebrospinal fluid [CSF] and plasma), age stratification, pleocytosis status, viral load, and EV genotype, which allows a comprehensive assessment of how age shapes both local and systemic immune responses during EV meningitis. This study shows that the immunological response to EV meningitis in CSF and plasma evolves with the age of the patients. The expression of cytokines/chemokines varied with CSF pleocytosis but not with EV types and viral load. Our findings highlight that neonatal EV meningitis is associated with distinct immunopathogenic features that reflect age-dependent immune responses. These results indicate that age stratification is essential in future studies aiming to evaluate cytokines and chemokines as biomarkers of disease severity in EV-associated neurological infections.

In early 2024, an outbreak of acute hemorrhagic conjunctivitis occurred in Mayotte and in Madagascar, two islands in the Indian Ocean. Real-time diagnosis and genotyping identified a different lineage of coxsackievirus A24 variant (CVA24v) from the current Asian outbreak. Although no recombination event had been detected in all previously reported CVA24v-associated outbreaks associated with the subgenotype IV, we characterized a putative recombinant strain by full-length genome sequencing.

BACKGROUND:The human parvovirus B19 (B19V) infections cycle occurs in 3- to 4-year periods and is responsible for benign childhood erythema infectiosum. It is also associated with transient aplastic crisis in patients with underlying hemolytic diseases and with severe fetal sometimes fatal infection. This study investigated the epidemiological, clinical and molecular characteristics of an unusually large 2023-2024 outbreak of B19V. METHODS:Laboratory-confirmed cases were retrospectively and prospectively recorded at the Clermont-Ferrand University Hospital, France, between January, 2018 and November, 2023 and between December 2023 and May 2024 (2023/2024), respectively. Demographical and clinical data were investigated for the 2023/2024 period. Subgenome sequences (2690 nt) were obtained by next generation sequencing for virus genotyping and temporal molecular analysis. RESULTS:The positive rate of B19V positive laboratory-confirmed cases was seven times higher between December 2023 and May 2024 than in the previous 5-year period (14.6 % vs 2.1 %, p < 0.001). No atypical clinical presentation or increased pathogenicity were observed, but this large outbreak resulted in a higher number of severe infections in pregnant women (8/16, 50.0 % of fetal complications) and those with chronic anemia. Phylogenetic analysis revealed that the 2023/2024 outbreak in France and Europe was mainly driven by a pre-existing lineage of B19V 1a subgenotype that emerged in 2017 (95 % highest posterior density interval: 2000-2018). CONCLUSIONS:The recent epidemic of B19V infections re-illustrates the immunity gap of the post-pandemic COVID-19 pandemic. This highlight the impact of any outbreak on at-risk population and the need for a more global and genomic surveillance.

Human Parvovirus B19 (B19V) is rarely observed in patients with Guillain-Barré syndrome. We report the case of a patient with rapidly progressive functional impotence of the limbs. B19V was detected in both blood and CSF samples. The patient improved clinically after plasma exchanges, but mild functional impotence persisted 2 months later.

Objective Patients with X linked agammaglobulinemia are susceptible to enterovirus (EV) infections. Similarly, severe EV infections have been described in patients with impaired B-cell response following treatment with anti-CD20 monoclonal antibodies (mAbs), mostly in those treated for haematological malignancies. We aimed to describe severe EV infections in patients receiving anti-CD20 mAbs for immune-mediated inflammatory diseases (IMIDs).Methods Patients were included following a screening of data collected through the routine surveillance of EV infections coordinated by the National Reference Center and a review of the literature. Additionally, neutralising antibodies were assessed in a patient with chronic EV-A71 meningoencephalitis.Results Nine original and 17 previously published cases were retrieved. Meningoencephalitis (n=21/26, 81%) associated with EV-positive cerebrospinal fluid (n=20/22, 91%) was the most common manifestation. The mortality rate was high (27%). EV was the only causal agents in all reported cases. Patients received multiple anti-CD20 mAbs infusions (median 8 (5-10)), resulting in complete B-cell depletion and moderate hypogammaglobulinemia (median 4.9 g/L (4.3-6.7)), and had limited concomitant immunosuppressive treatments. Finally, in a patient with EV-A71 meningoencephalitis, a lack of B-cell response to EV was shown.Conclusion EV infection should be evoked in patients with IMIDs presenting with atypical organ involvement, especially meningoencephalitis. Anti-CD20 mAbs may lead to impaired B-cell response against EV, although an underlying primary immunodeficiency should systematically be discussed.

ABSTRACT Enterovirus A71 (EV-A71) is associated with neurological conditions such as acute meningitis and encephalitis. The virus is detected in the bloodstream, and high blood viral loads are associated with central nervous system (CNS) manifestations. We used an in vitro blood–brain barrier (BBB) model made up of human brain-like endothelial cells (hBLECs) and brain pericytes grown in transwell systems to investigate whether three genetically distinct EV-A71 strains (subgenogroups C1, C1-like, and C4) can cross the human BBB. EV-A71 poorly replicated in hBLECs, which released moderate amounts of infectious viruses from their luminal side and trace amounts of infectious viruses from their basolateral side. The barrier properties of hBLECs were not impaired by EV-A71 infection. We investigated the passage through hBLECs of EV-A71-infected white blood cells. EV-A71 strains efficiently replicated in immune cells, including monocytes, neutrophils, and NK/T cells. Attachment to hBLECs of immune cells infected with the C1-like virus was higher than attachment of cells infected with C1-06. EV-A71 infection did not impair the transmigration of immune cells through hBLECs. Overall, EV-A71 targets different white blood cell populations that have the potential to be used as a Trojan horse to cross hBLECs more efficiently than cell-free EV-A71 particles. IMPORTANCE Enterovirus A71 (EV-A71) was first reported in the USA, and numerous outbreaks have since occurred in Asia and Europe. EV-A71 re-emerged as a new multirecombinant strain in 2015 in Europe and is now widespread. The virus causes hand-foot-and-mouth disease in young children and is involved in nervous system infections. How the virus spreads to the nervous system is unclear. We investigated whether white blood cells could be infected by EV-A71 and transmit it across human endothelial cells mimicking the blood–brain barrier protecting the brain from adverse effects. We found that endothelial cells provide a strong roadblock to prevent the passage of free virus particles but allow the migration of infected immune cells, including monocytes, neutrophils, and NK/T cells. Our data are consistent with the potential role of immune cells in the pathogenesis of EV-A71 infections by spreading the virus in the blood and across the human blood–brain barrier.

Phosphorylation is a major post-translation modification (PTM) of proteins which is finely tuned by the activity of several hundred kinases and phosphatases. It controls most if not all cellular pathways including anti-viral responses. Accordingly, viruses often induce important changes in the phosphorylation of host factors that can either promote or counteract viral replication. Among more than 500 kinases constituting the human kinome only few have been described as important for the hepatitis B virus (HBV) infectious cycle, and most of them intervene during early or late infectious steps by phosphorylating the viral Core (HBc) protein. In addition, little is known on the consequences of HBV infection on the activity of cellular kinases. The objective of this study was to investigate the global impact of HBV infection on the cellular phosphorylation landscape early after infection. For this, primary human hepatocytes (PHHs) were challenged or not with HBV, and a mass spectrometry (MS)-based quantitative phosphoproteomic analysis was conducted 2- and 7-days post-infection. The results indicated that while, as expected, HBV infection only minimally modified the cell proteome, significant changes were observed in the phosphorylation state of several host proteins at both time points. Gene enrichment and ontology analyses of up- and down-phosphorylated proteins revealed common and distinct signatures induced by infection. In particular, HBV infection resulted in up-phosphorylation of proteins involved in DNA damage signaling and repair, RNA metabolism, in particular splicing, and cytoplasmic cell-signaling. Down-phosphorylated proteins were mostly involved in cell signaling and communication. Validation studies carried out on selected up-phosphorylated proteins, revealed that HBV infection induced a DNA damage response characterized by the appearance of 53BP1 foci, the inactivation of which by siRNA increased cccDNA levels. In addition, among up-phosphorylated RNA binding proteins (RBPs), SRRM2, a major scaffold of nuclear speckles behaved as an antiviral factor. In accordance with these findings, kinase prediction analysis indicated that HBV infection upregulates the activity of major kinases involved in DNA repair. These results strongly suggest that HBV infection triggers an intrinsic anti-viral response involving DNA repair factors and RBPs that contribute to reduce HBV replication in cell culture models.

The COVID-19 pandemic, driven by SARS-CoV-2, led authorities to recommend halting assisted reproductive technology programs, focusing instead on fertility preservation, for cancer patients. The presence of SARS-CoV-2 in semen remains controversial. This multicentric prospective cohort study, conducted across 12 university medical centers, aimed to determine if SARS-CoV-2 is present in spermatozoa/seminal plasma in cancer patients by RT-PCR and to assess its impact on standard semen parameters. The levels of cytokines and TNF-alpha were measured in seminal fluid by ELISA. We enrolled 129 men who underwent sperm cryopreservation between July 7, 2020, and June 30, 2021. The 63 were included and tested for COVID-19 in nasal swab samples by RT-PCR and/or by serology. All patients were asymptomatic on the day of semen collection: 50 were uninfected, 8 had a positive nasal swab (PCR+) and 5 were seropositive. SARS-CoV-2 RNA was not detected in the seminal fluid or spermatozoa. Ejaculate volume was significantly lower in the PCR+ group compared to the uninfected group (median [IQR]: 2.6 mL [1.6-3.4] vs. 4.6 mL [2.6-5.2] p < 0.05). Total and progressive motility were lower in the PCR+ group compared to the seropositive group (32.5% [25.0-45.0] vs. 50% [49.0-55.0] p < 0.05, and 22.5% [10.0; 32.5] vs. 44.5% [40-49] p < 0.05). Higher TNF-alpha level was observed in the PCR+ group (1.9 pg/mL [0-3.9]) compared to the uninfected group (0 pg/mL [0-0.4]) p < 0.05. Although SARS-CoV-2 was not detected in the sperm samples of cancer patients who were PCR+, the infection appears to impact sperm parameters, likely due to inflammation.

The third, "booster", vaccination increases the overall immune response against SARS-CoV-2 variants. However, after the initial peak at around 3 weeks post-vaccination, anti-spike antibody levels decline. Post-booster kinetics of cellular response has been less investigated and there is no documented evidence of a true boosting effect. Furthermore, multiple studies underline the less effective immune responses against Omicron, the latest variant of concern, at both humoral and cellular levels. In this letter, we analyse humoral (anti-RBD IgG levels) and cellular (IFN-γ release assay) immune response in 205 health care workers 3 weeks and 3 months after administration of an mRNA-based booster dose, either mRNA-1273 or BNT162b2. Since all subjects were SARS-CoV-2 infection-naïve, we also looked at the incidence of Omicron infection between 3 and 6 months post-booster.At both timepoints, 3x mRNA-1273 vaccination had the highest overall antibody and IFN-γ levels, followed by 3x BNT162b2 vaccination and heterologous mRNA-based regimens. Heterologous ChAdOx1-mRNA-based regimen had the lowest antibody levels while cellular response equal to that of 3x BNT162b2 vaccination and heterologous mRNA-based regimens. Our results show that both humoral and cellular responses waned at 3 months for all vaccination regimens. However, we identified three trajectories of dosage variation. Interestingly, the subgroup of subjects with increasing anti-RBD IgG levels over time had a lower incidence of Omicron infection. Whether increasing humoral response at 3 months post-booster is more indicative of protection than a high initial peak remains to be confirmed in a larger cohort.

We report evidence of Delta/Omicron SARS-CoV-2 co-infections during the fifth wave of COVID-19 pandemics in France for 7 immunocompetent and epidemiologically unrelated patients. These co-infections were detected by PCR assays targeting SARS-CoV-2 S-gene mutations K417N and L452R and confirmed by whole genome sequencing which allowed the proportion estimation of each subpopulation. For 2 patients, the analyses of longitudinal samples collected 7 to 11 days apart showed that Delta or Omicron can outcompete the other variant during dual infection.

Objectives: To describe Delta/Omicron SARS-CoV-2 variants co-infection detection and confirmation during the fifth wave of COVID-19 pandemics in France in 7 immunocompetent and epidemiologically unrelated patients. Methods: Since December 2021, the surveillance of Delta/Omicron SARS-CoV-2 variants of concern (VOC) circulation was performed through prospective screening of positive-samples using single nucleotide polymorphism (SNP) PCR assays targeting SARS-CoV-2 S-gene mutations K417N (Omicron specific) and L452R (Delta specific). Samples showing unexpected mutational profiles were further submitted to whole genome sequencing (WGS) using three different primer sets. Results: Between weeks 49-2021 and 02-2022, SARS-CoV-2 genome was detected in 3831 respiratory samples, of which 3237 (84.5%) were screened for VOC specific SNPs. Unexpected mutation profiles suggesting a dual Delta/Omicron population were observed in 7 nasopharyngeal samples (0.2%). These co-infections were confirmed by WGS. For 2 patients, the sequence analyses of longitudinal samples collected 7 to 11 days apart showed that Delta or Omicron can outcompete the other variant during dual infection. Additionally, for one of these samples, a recombination event between Delta and Omicron was detected. Conclusions: This work demonstrates that SARS-CoV-2 Delta/Omicron co-infections are not rare in high virus co-circulation periods. Moreover, co-infections can further lead to genetic recombination which may generate new chimeric variants with unpredictable epidemic or pathogenic properties that could represent a serious health threat. (C) 2022 The Authors. Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases.

Research question: Is it possible to validate an accurate and reliable method for direct detection of SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR) in human semen fractions?Design: This qualitative improvement study aimed to provide a prospective validation of SARS-CoV-2 detection in male semen. The SARS-CoV-2 genome was detected by multiplex real-time RT-PCR on patient samples that underwent routine semen analyses for infertility at the Center for Reproductive Medicine at the University Hospital of Clermont-Ferrand. Samples comprised surplus semen collected for treatment with assisted reproductive technology. Seminal fluid and spermatozoa fractions were isolated with density gradient centrifugation and cryopreserved. Positive samples were prepared with a standard of inactivated SARS-CoV-2 particles.Results: The analytical method was validated in both seminal fluid and spermatozoa fractions. In both semen fractions, the assay was repeatable, reproducible and showed high sensitivity with a limit of detection of 0.33 SARS-CoV-2 genome copies/pl. The limit of quantification was 1 copy of the SARS-CoV-2 genome/pl. The method was effective regardless of semen quality (normal and altered sperm parameters), number of spermatozoa or the cryoprotectant media used to freeze spermatozoa.Conclusion: This validated RT-PCR assay provided accurate and reliable screening of SARS-CoV-2 in seminal fluid and spermatozoa fractions. This method is essential to ensure protection against viral contamination in the cryobanking process.

Clinical trials and real-world evidence on COVID-19 vaccines have shown their effectiveness against severe disease and death but the durability of protection remains unknown. We analysed the humoral and T-cell immune responses in 110 healthcare workers (HCWs) vaccinated according to the manufacturer’s recommended schedule of dose 2 three weeks after dose 1 from a prospective on-going cohort in early 2021, 3 and 6 months after full vaccination with the BNT162b2 mRNA vaccine. Anti-RBD IgG titres were lower in HCWs over 60 years old 3 months after the second dose (p=0.03) and declined in all the subjects between 3 and 6 months with a median percentage change of -58.5%, irrespective of age and baseline comorbidities. Specific T-cell response measured by IGRA declined over time by at least 42% (median) in 91 HCWs and increased by 33% (median) in 17 others. Six HCWs had a negative T-cell response at 6 months. Ongoing follow-up should provide correlates of long-term protection according to the different immune response profiles observed. COVIDIM study was registered under the number NCT04896788 on clinicaltrials.gov.

Differences in effectiveness against severe disease were initially observed between COVID-19 vaccines during the period of predominance of the SARS-CoV-2 Alpha (B.1.1.7) variant, with mRNA vaccines (BNT162b2 and mRNA-1273) being more effective than the adenovirus-vectored ChAdOx1 vaccine.1Polack F.P. Thomas S.J. Kitchin N. Absalon J. Gurtman A. Lockhart S. et al.Safety and efficacy of the BNT162b2 mRNA Covid-19 Vaccine.N Engl J Med. 2020; 383: 2603-2615Crossref PubMed Scopus (6139) Google Scholar, 2Baden L.R. El Sahly H.M. Essink B. Kotloff K. Frey S. Novak R. et al.Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine.N Engl J Med. 2021; 384: 403-416Crossref PubMed Scopus (4008) Google Scholar, 3Voysey M. Clemens S.A.C. Madhi S.A. Weckx L.Y. Folegatti P.M. Aley P.K. et al.Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.Lancet. 2021; 397: 99-111Abstract Full Text Full Text PDF PubMed Scopus (2313) Google Scholar After the emergence of the Delta (B.1.617.2) variant, a modest decrease in protection was noted after two doses of all vaccines. However, effectiveness against mild infection was substantially attenuated in comparison to Alpha variant, especially for the ChAdOx1 vaccine.4Lopez Bernal J. Andrews N. Gower C. Gallagher E. Simmons R. Thelwall S. et al.Effectiveness of Covid-19 vaccines against the B.1.617.2 (Delta) variant.N Engl J Med. 2021; 385: 585-594Crossref PubMed Scopus (1207) Google Scholar, 5Thiruvengadam R. Awasthi A. Medigeshi G. Bhattacharya S. Mani S. Sivasubbu S. et al.Effectiveness of ChAdOx1 nCoV-19 vaccine against SARS-CoV-2 infection during the delta (B.1.617.2) variant surge in India: a test-negative, case-control study and a mechanistic study of post-vaccination immune responses.Lancet Infect Dis. 2021; (Available at https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00680-0/fulltext, In press. Accessed 20 December 2021)Google Scholar, 6Bruxvoort K.J. Sy L.S. Qian L. Ackerson B.K. Luo Y. Lee G.S. et al.Effectiveness of mRNA-1273 against delta, mu, and other emerging variants of SARS-CoV-2: test negative case-control study.BMJ. 2021; 375e068848PubMed Google Scholar First data indicate that waning of protection against reinfection and symptomatic infection is faster for Omicron (B.1. 1.529) than for Delta infections.[7]SARS-CoV-2 variants of concern and variants under investigation. UK Health Security Agency 2021;43.Google Scholar We read with interest the article by Ferré et al., showing a drastic waning of antibody response 3 months after the second dose of BNT162b2 in healthcare workers (HCWs) associated with a loss of neutralization activities against variant strains.8Ferré V.M. Lebourgeois S. Menidjel R. Collin G. Chenane H.R. Guindi M.O. et al.Decreasing humoral response among healthcare workers up to 4 months after two doses of BNT162b2 vaccine.J Infect. 2022; 84: 248-288Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar Nevertheless, the assessment of T-cell responses, crucial for protection against SARS-CoV-2 infection and disease severity, has not been performed. To better understand differences of risk of COVID-19-related outcomes, we need for supportive studies that evaluate the comparative immunogenicity conferred by different vaccines and vaccination strategies and their durability.In a prospective longitudinal cohort (COVIDIM Study) of HCWs, we analysed immune response 3 and 6 months after full vaccination against SARS-CoV-2 with either mRNA-1273, BNT162b2 and/or ChAdOx1 vaccines. SARS-CoV-2 anti-RBD IgG responses were quantified by an enzyme-linked immunosorbent assay (SARS-CoV-2 IgG II Quant assay, Abbott, Chicago, USA). Memory SARS-CoV-2-specific T-cell responses were quantitatively analyzed by an interferon-gamma (IFN-γ) release assay (IGRA) (QuantiFERON SARS-CoV-2, Qiagen, Hilden, Germany) in response to stimulation by SARS-CoV-2 spike antigens. Antibody and specific-IFN-γ levels were compared between independent groups (according to vaccine types and participants previously infected vs uninfected) with the Mann-Whitney test. All tests were two-sided, with a Type I error set at 0.05.We enrolled 300 participants who had received one (n = 27, because of previous SARS-CoV-2 infection) or two doses (n = 273) of vaccine during February –June 2021. The mean age of HCWs was 46.4 ± 11.1 years, and 84.7% were female. We compared immune responses 3 months (96.0 ± 11.4 days) and 6 months (174.0 ± 8.4 days) after the last dose of each vaccine for the entire cohort and for previously infected vs uninfected HCWs. Previous infection was defined as anti-nucleocapsid positivity (SARS-CoV-2 IgG assay, Abbott) and/or history of positive PCR result on nasopharyngeal swab.Among uninfected HCWs, anti-RBD IgG levels after 2-dose mRNA-1273 vaccine were significantly higher at M3 than those induced by 2-dose BNT162b2 vaccine (p < 0.0001), 2-dose-ChAdOx1 vaccine (p = 0.001) or the heterologous ChAdOx1 / BNT162b2 prime-boost vaccination (p < 0.0001) (Fig. 1). 2-dose BNT162b2 induced a higher anti-RBD IgG response than 2-dose ChAdOx1 (p = 0.003) but the heterologous ChAdOx1/BNT162b2 prime-boost vaccination achieved an antibody response comparable to that of 2-dose BNT162b2 (p = 0.26) (Fig. 1). Analysis of spike-specific T-cell response at M3 confirmed the greater immunogenic properties of 2-dose mRNA-1273 than 2-dose BNT162b2 (p = 0.02), which seems to induce a higher immune response than 2-dose ChAdOx1. However, the difference was not significant (p = 0.09) probably due to the small number of individuals in this group (Fig. 1). The heterologous ChAdOx1 / BNT162b2 vaccination achieved the same level of cellular immune response as the 2-dose mRNA-1273 (p = 0.53) or BNT162b2 (p = 0.08) vaccines (Fig. 1).A significant waning of antibody response induced by vaccines was observed between M3 and M6 in uninfected COVID-19 HCWs, with a median decline of anti-RBD IgG titers by 65.3% [59.3 - 72.2] with 2-dose mRNA-1273, 61.5% [54.9–68.7] with 2-dose BNT162b2, 51.2% [48.9–54.8] with 2-dose ChAdOx1 and 61.5% [55.9 - 67.0] with ChAdOx1/BNT162b2. Hence, the highest anti-RBD IgG titer 6 months after vaccination was elicited by 2-dose mRNA-1273, followed by 2-dose BNT162b2 or the heterologous ChAdOx1/BNT162b2 vaccination and finally by 2-dose ChAdOx1 (Fig. 1). Similarly, spike-specific T-cell response had a median decline over time between M3 and M6 of 26.3% [6.9–49.7] with 2-dose mRNA-1273, 40.0% [6.7 - 61.1] with 2-dose BNT162b2, 17.6% [0.0–51.5] with 2-dose ChAdOx1 and 38.8% [17.3–63.7] with the heterologous ChAdOx1/BNT162b2 vaccination. The highest specific IFN-γ response 6 months after vaccination was elicited by mRNA-1273, followed by BNT162b2 equal to ChAdOx1/BNT162b2, and finally by ChAdOx1 (Fig. 1).In previously SARS-CoV-2-infected vaccinees with a single dose, antibody responses at M3 exceeded those found in uninfected HCWs fully vaccinated with mRNA-1273 (p = 0.03), BNT162b2 (p < 0.0001), and ChAdOx1 (p = 0.03) vaccines. At M6, we observed similar drop values to those measured in uninfected HCWs, and anti-RBD IgG titers remained higher at M6 in previously SARS-CoV-2-infected than in uninfected HCWs for each vaccine (mRNA-1273 (p = 0.07); BNT162b2 (p < 0.001); and ChAdOx1 (p = 0.01)) (Fig. 1). Analysis of spike-specific T-cell response confirmed the greater immunogenic properties of the mRNA-1273 vaccine at M3 and M6 than those of the others vaccines (Fig. 1). Specific IFN-γ response induced by a single vaccine dose of mRNA-1273 in previously infected HCWs exceeded at M3 and M6 that induced by 2-dose mRNA-1273 in uninfected HCWs (p = 0.02 and p = 0.03, respectively). In contrast, no difference was found between the two groups for BNT162b2 or ChAdOx1 vaccines.We report the variable immunogenicity elicited by four different strategies of COVID-19 vaccines 3 months and 6 months after a primary course of vaccination. Our results confirm differences previously observed in side-to-side comparisons of vaccines early after vaccination and show that these differences last over time. Six months after vaccination, HCWs in both groups (uninfected and infected) vaccinated with mRNA-1273 had higher antibody titers and anti-spike T-cell response than those vaccinated with BNT162b2. However, the difference in immunogenicity according to previous infection was greater than the difference between the 2 mRNA vaccines. These results are consistent with those reported 3 to 10 weeks after vaccination.9Naranbhai V. Garcia-Beltran W.F. Chang C.C. Mairena C.B. Thierauf J.C. Kirkpatrick G. et al.Comparative immunogenicity and effectiveness of mRNA-1273, BNT162b2 and Ad26.COV2.S COVID-19 vaccines.J Infect Dis. 2021; : jiab593Google Scholar,10Steensels D. Pierlet N. Penders J. Mesotten D. Heylen L. Comparison of SARS-CoV-2 antibody response following vaccination with BNT162b2 and mRNA-1273.JAMA. 2021; 326: 1533-1535Crossref PubMed Scopus (148) Google Scholar Previous studies indicated that a heterologous vaccination schedule with a first dose of ChAdOx1 followed by a second dose of mRNA vaccine provided higher antibody response one month after the boost than 2-dose ChAdOx1.11Liu X. Shaw R.H. Stuart A.S.V. Greenland M. Aley P.K. Andrews N.J. et al.Safety and immunogenicity of heterologous versus homologous prime-boost schedules with an adenoviral vectored and mRNA COVID-19 vaccine (Com-COV): a single-blind, randomised, non-inferiority trial.Lancet. 2021; 398: 856-869Abstract Full Text Full Text PDF PubMed Scopus (192) Google Scholar Our results indicate that the greater effectiveness of ChAdOx1/BNT162b2 prime-boost vaccination was maintained for up to 6 months, and conferred humoral and cellular response similar to that of 2-dose BNT162b2. The clinical effectiveness of vaccines requires on-going (re) evaluation, particularly in the context of the emergence of variants of concern. Further long-term studies on the effect of booster vaccines (recommended since the late 2021) should help us to assess the dynamics of immunogenicity according to the vaccination regimens used over time and to validate the most effective vaccination strategies.FundingThe COVIDIM study is funded by the Clinical Research and Innovation Direction of the Clermont-Ferrand University hospital.Ethical approvalResearch involving human subjects complied with all relevant national regulations, institutional policies and is in accordance with the tenets of the Helsinki Declaration (as revised in 2013), and has been approved by the Ile-de-France VIII ethics committee of France and registered on ClinicalTrials.gov (NCT04896788).Informed consentWritten informed consent was obtained from all individuals included in this study.Author contributionsC.H., B.E. and B.P. planned the research; B.B, C.A., A.B., J.C., F.D., M.J., A.M., C.R., M.V., B.E. and C.H. performed the enrollment of participants in the COVIDIM study; A.O. managed the study; B.B and H.C. analyzed the data; C.L. and B.B realized the statistic tests; B.B., B.E and C.H wrote the paper. All authors have accepted responsibility for the entire content of this manuscript and approved its submission.Data availabilityThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Differences in effectiveness against severe disease were initially observed between COVID-19 vaccines during the period of predominance of the SARS-CoV-2 Alpha (B.1.1.7) variant, with mRNA vaccines (BNT162b2 and mRNA-1273) being more effective than the adenovirus-vectored ChAdOx1 vaccine.1Polack F.P. Thomas S.J. Kitchin N. Absalon J. Gurtman A. Lockhart S. et al.Safety and efficacy of the BNT162b2 mRNA Covid-19 Vaccine.N Engl J Med. 2020; 383: 2603-2615Crossref PubMed Scopus (6139) Google Scholar, 2Baden L.R. El Sahly H.M. Essink B. Kotloff K. Frey S. Novak R. et al.Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine.N Engl J Med. 2021; 384: 403-416Crossref PubMed Scopus (4008) Google Scholar, 3Voysey M. Clemens S.A.C. Madhi S.A. Weckx L.Y. Folegatti P.M. Aley P.K. et al.Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.Lancet. 2021; 397: 99-111Abstract Full Text Full Text PDF PubMed Scopus (2313) Google Scholar After the emergence of the Delta (B.1.617.2) variant, a modest decrease in protection was noted after two doses of all vaccines. However, effectiveness against mild infection was substantially attenuated in comparison to Alpha variant, especially for the ChAdOx1 vaccine.4Lopez Bernal J. Andrews N. Gower C. Gallagher E. Simmons R. Thelwall S. et al.Effectiveness of Covid-19 vaccines against the B.1.617.2 (Delta) variant.N Engl J Med. 2021; 385: 585-594Crossref PubMed Scopus (1207) Google Scholar, 5Thiruvengadam R. Awasthi A. Medigeshi G. Bhattacharya S. Mani S. Sivasubbu S. et al.Effectiveness of ChAdOx1 nCoV-19 vaccine against SARS-CoV-2 infection during the delta (B.1.617.2) variant surge in India: a test-negative, case-control study and a mechanistic study of post-vaccination immune responses.Lancet Infect Dis. 2021; (Available at https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00680-0/fulltext, In press. Accessed 20 December 2021)Google Scholar, 6Bruxvoort K.J. Sy L.S. Qian L. Ackerson B.K. Luo Y. Lee G.S. et al.Effectiveness of mRNA-1273 against delta, mu, and other emerging variants of SARS-CoV-2: test negative case-control study.BMJ. 2021; 375e068848PubMed Google Scholar First data indicate that waning of protection against reinfection and symptomatic infection is faster for Omicron (B.1. 1.529) than for Delta infections.[7]SARS-CoV-2 variants of concern and variants under investigation. UK Health Security Agency 2021;43.Google Scholar We read with interest the article by Ferré et al., showing a drastic waning of antibody response 3 months after the second dose of BNT162b2 in healthcare workers (HCWs) associated with a loss of neutralization activities against variant strains.8Ferré V.M. Lebourgeois S. Menidjel R. Collin G. Chenane H.R. Guindi M.O. et al.Decreasing humoral response among healthcare workers up to 4 months after two doses of BNT162b2 vaccine.J Infect. 2022; 84: 248-288Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar Nevertheless, the assessment of T-cell responses, crucial for protection against SARS-CoV-2 infection and disease severity, has not been performed. To better understand differences of risk of COVID-19-related outcomes, we need for supportive studies that evaluate the comparative immunogenicity conferred by different vaccines and vaccination strategies and their durability. In a prospective longitudinal cohort (COVIDIM Study) of HCWs, we analysed immune response 3 and 6 months after full vaccination against SARS-CoV-2 with either mRNA-1273, BNT162b2 and/or ChAdOx1 vaccines. SARS-CoV-2 anti-RBD IgG responses were quantified by an enzyme-linked immunosorbent assay (SARS-CoV-2 IgG II Quant assay, Abbott, Chicago, USA). Memory SARS-CoV-2-specific T-cell responses were quantitatively analyzed by an interferon-gamma (IFN-γ) release assay (IGRA) (QuantiFERON SARS-CoV-2, Qiagen, Hilden, Germany) in response to stimulation by SARS-CoV-2 spike antigens. Antibody and specific-IFN-γ levels were compared between independent groups (according to vaccine types and participants previously infected vs uninfected) with the Mann-Whitney test. All tests were two-sided, with a Type I error set at 0.05. We enrolled 300 participants who had received one (n = 27, because of previous SARS-CoV-2 infection) or two doses (n = 273) of vaccine during February –June 2021. The mean age of HCWs was 46.4 ± 11.1 years, and 84.7% were female. We compared immune responses 3 months (96.0 ± 11.4 days) and 6 months (174.0 ± 8.4 days) after the last dose of each vaccine for the entire cohort and for previously infected vs uninfected HCWs. Previous infection was defined as anti-nucleocapsid positivity (SARS-CoV-2 IgG assay, Abbott) and/or history of positive PCR result on nasopharyngeal swab. Among uninfected HCWs, anti-RBD IgG levels after 2-dose mRNA-1273 vaccine were significantly higher at M3 than those induced by 2-dose BNT162b2 vaccine (p < 0.0001), 2-dose-ChAdOx1 vaccine (p = 0.001) or the heterologous ChAdOx1 / BNT162b2 prime-boost vaccination (p < 0.0001) (Fig. 1). 2-dose BNT162b2 induced a higher anti-RBD IgG response than 2-dose ChAdOx1 (p = 0.003) but the heterologous ChAdOx1/BNT162b2 prime-boost vaccination achieved an antibody response comparable to that of 2-dose BNT162b2 (p = 0.26) (Fig. 1). Analysis of spike-specific T-cell response at M3 confirmed the greater immunogenic properties of 2-dose mRNA-1273 than 2-dose BNT162b2 (p = 0.02), which seems to induce a higher immune response than 2-dose ChAdOx1. However, the difference was not significant (p = 0.09) probably due to the small number of individuals in this group (Fig. 1). The heterologous ChAdOx1 / BNT162b2 vaccination achieved the same level of cellular immune response as the 2-dose mRNA-1273 (p = 0.53) or BNT162b2 (p = 0.08) vaccines (Fig. 1). A significant waning of antibody response induced by vaccines was observed between M3 and M6 in uninfected COVID-19 HCWs, with a median decline of anti-RBD IgG titers by 65.3% [59.3 - 72.2] with 2-dose mRNA-1273, 61.5% [54.9–68.7] with 2-dose BNT162b2, 51.2% [48.9–54.8] with 2-dose ChAdOx1 and 61.5% [55.9 - 67.0] with ChAdOx1/BNT162b2. Hence, the highest anti-RBD IgG titer 6 months after vaccination was elicited by 2-dose mRNA-1273, followed by 2-dose BNT162b2 or the heterologous ChAdOx1/BNT162b2 vaccination and finally by 2-dose ChAdOx1 (Fig. 1). Similarly, spike-specific T-cell response had a median decline over time between M3 and M6 of 26.3% [6.9–49.7] with 2-dose mRNA-1273, 40.0% [6.7 - 61.1] with 2-dose BNT162b2, 17.6% [0.0–51.5] with 2-dose ChAdOx1 and 38.8% [17.3–63.7] with the heterologous ChAdOx1/BNT162b2 vaccination. The highest specific IFN-γ response 6 months after vaccination was elicited by mRNA-1273, followed by BNT162b2 equal to ChAdOx1/BNT162b2, and finally by ChAdOx1 (Fig. 1). In previously SARS-CoV-2-infected vaccinees with a single dose, antibody responses at M3 exceeded those found in uninfected HCWs fully vaccinated with mRNA-1273 (p = 0.03), BNT162b2 (p < 0.0001), and ChAdOx1 (p = 0.03) vaccines. At M6, we observed similar drop values to those measured in uninfected HCWs, and anti-RBD IgG titers remained higher at M6 in previously SARS-CoV-2-infected than in uninfected HCWs for each vaccine (mRNA-1273 (p = 0.07); BNT162b2 (p < 0.001); and ChAdOx1 (p = 0.01)) (Fig. 1). Analysis of spike-specific T-cell response confirmed the greater immunogenic properties of the mRNA-1273 vaccine at M3 and M6 than those of the others vaccines (Fig. 1). Specific IFN-γ response induced by a single vaccine dose of mRNA-1273 in previously infected HCWs exceeded at M3 and M6 that induced by 2-dose mRNA-1273 in uninfected HCWs (p = 0.02 and p = 0.03, respectively). In contrast, no difference was found between the two groups for BNT162b2 or ChAdOx1 vaccines. We report the variable immunogenicity elicited by four different strategies of COVID-19 vaccines 3 months and 6 months after a primary course of vaccination. Our results confirm differences previously observed in side-to-side comparisons of vaccines early after vaccination and show that these differences last over time. Six months after vaccination, HCWs in both groups (uninfected and infected) vaccinated with mRNA-1273 had higher antibody titers and anti-spike T-cell response than those vaccinated with BNT162b2. However, the difference in immunogenicity according to previous infection was greater than the difference between the 2 mRNA vaccines. These results are consistent with those reported 3 to 10 weeks after vaccination.9Naranbhai V. Garcia-Beltran W.F. Chang C.C. Mairena C.B. Thierauf J.C. Kirkpatrick G. et al.Comparative immunogenicity and effectiveness of mRNA-1273, BNT162b2 and Ad26.COV2.S COVID-19 vaccines.J Infect Dis. 2021; : jiab593Google Scholar,10Steensels D. Pierlet N. Penders J. Mesotten D. Heylen L. Comparison of SARS-CoV-2 antibody response following vaccination with BNT162b2 and mRNA-1273.JAMA. 2021; 326: 1533-1535Crossref PubMed Scopus (148) Google Scholar Previous studies indicated that a heterologous vaccination schedule with a first dose of ChAdOx1 followed by a second dose of mRNA vaccine provided higher antibody response one month after the boost than 2-dose ChAdOx1.11Liu X. Shaw R.H. Stuart A.S.V. Greenland M. Aley P.K. Andrews N.J. et al.Safety and immunogenicity of heterologous versus homologous prime-boost schedules with an adenoviral vectored and mRNA COVID-19 vaccine (Com-COV): a single-blind, randomised, non-inferiority trial.Lancet. 2021; 398: 856-869Abstract Full Text Full Text PDF PubMed Scopus (192) Google Scholar Our results indicate that the greater effectiveness of ChAdOx1/BNT162b2 prime-boost vaccination was maintained for up to 6 months, and conferred humoral and cellular response similar to that of 2-dose BNT162b2. The clinical effectiveness of vaccines requires on-going (re) evaluation, particularly in the context of the emergence of variants of concern. Further long-term studies on the effect of booster vaccines (recommended since the late 2021) should help us to assess the dynamics of immunogenicity according to the vaccination regimens used over time and to validate the most effective vaccination strategies. FundingThe COVIDIM study is funded by the Clinical Research and Innovation Direction of the Clermont-Ferrand University hospital. The COVIDIM study is funded by the Clinical Research and Innovation Direction of the Clermont-Ferrand University hospital.

We report a large-scale outbreak of hand, foot and mouth disease (HFMD) in France. As at 28 September 2021, 3,403 cases have been reported (47% higher than in 2018-19). We prospectively analysed 210 clinical samples; 190 (90.5%) were enterovirus-positive. Most children presented with atypical HFMD. Coxsackievirus (CV)A6 (49.5%; 94/190) was predominant; no enterovirus A71 was detected. Dermatological and neurological complications of HFMD justify prospective syndromic and virological surveillance for early detection of HFMD outbreaks and identification of associated types.

Despite the existence of a preventive vaccine, chronic infection with Hepatitis B virus (HBV) affects more than 250 million people and represents a major global cause of hepatocellular carcinoma (HCC) worldwide. Current clinical treatments, in most of cases, do not eliminate viral genome that persists as a DNA episome in the nucleus of hepatocytes and constitutes a stable template for the continuous expression of viral genes. Several studies suggest that, among viral factors, the HBV core protein (HBc), well-known for its structural role in the cytoplasm, could have critical regulatory functions in the nucleus of infected hepatocytes. To elucidate these functions, we performed a proteomic analysis of HBc-interacting host-factors in the nucleus of differentiated HepaRG, a surrogate model of human hepatocytes. The HBc interactome was found to consist primarily of RNA-binding proteins (RBPs), which are involved in various aspects of mRNA metabolism. Among them, we focused our studies on SRSF10, a RBP that was previously shown to regulate alternative splicing (AS) in a phosphorylation-dependent manner and to control stress and DNA damage responses, as well as viral replication. Functional studies combining SRSF10 knockdown and a pharmacological inhibitor of SRSF10 phosphorylation (1C8) showed that SRSF10 behaves as a restriction factor that regulates HBV RNAs levels and that its dephosphorylated form is likely responsible for the anti-viral effect. Surprisingly, neither SRSF10 knock-down nor 1C8 treatment modified the splicing of HBV RNAs but rather modulated the level of nascent HBV RNA. Altogether, our work suggests that in the nucleus of infected cells HBc interacts with multiple RBPs that regulate viral RNA metabolism. Our identification of SRSF10 as a new anti-HBV restriction factor offers new perspectives for the development of new host-targeted antiviral strategies.

Chronic infection by hepatitis B virus (HBV) is a major public health problem with more than 250 millions of people chronically infected worldwide who have a high risk to develop cirrhosis and hepatocellular carcinoma. Available treatments reduce viremia but do not eradicate the virus from hepatocytes. Therefore, there is an urgent need to develop new classes of antiviral molecules and the viral capsid protein, Core, constitutes a new favored target. Core protein Allosteric Modulators (CAMs) targeting its assembly functions are in clinical development. In addition, investigation of Core regulatory functions may lead to the development of compounds targeting cellular factors (HTA) that could be used in combined therapies aiming to achieve a better control of HBV replication.

L’infection par le virus de l’hépatite B (HBV) constitue un problème majeur de santé publique avec plus de 250 millions de personnes chroniquement infectées au niveau mondial, qui présentent un risque important d’évolution vers la cirrhose et le cancer du foie. Les traitements disponibles permettent de réduire la réplication virale mais pas d’éliminer le virus. Il est donc primordial de développer de nouvelles thérapies antivirales. Des modulateurs allostériques (ou CAM), qui interfèrent avec les fonctions structurales de Core, la protéine de capside du virus, sont actuellement en évaluation clinique. L’étude des fonctions régulatrices de la protéine Core pourrait également permettre d’identifier des agents ciblant l’hôte et de développer des thérapies combinées pour un meilleur contrôle de la réplication virale.