Human papillomavirus negative high grade cervical lesions and cancers: Suggested guidance for HPV testing quality assurance.

BACKGROUND: Some high-grade cervical lesions and cervical cancers (HSIL+) test negative for human papillomavirus (HPV). The HPV-negative fraction varies between 0.03 % and 15 % between different laboratories. Monitoring and extended re-analysis of HPV-negative HSIL+ could thus be helpful to monitor performance of HPV testing services. We aimed to a) provide a real-life example of a quality assurance (QA) program based on re-analysis of HPV-negative HSIL+ and b) develop international guidance for QA of HPV testing services based on standardized identification of apparently HPV-negative HSIL+ and extended re-analysis, either by the primary laboratory or by a national HPV reference laboratory (NRL). METHODS: There were 116 initially HPV-negative cervical specimens (31 histopathology specimens and 85 liquid-based cytology samples) sent to the Swedish HPV Reference Laboratory for re-testing. Based on the results, an international QA guidance was developed through an iterative consensus process. RESULT: Standard PCR testing detected HPV in 55.2 % (64/116) of initially "HPV-negative" samples. Whole genome sequencing of PCR-negative samples identified HPV in an additional 7 samples (overall 61.2 % HPV positivity). Reasons for failure to detect HPV in an HSIL+ lesion are listed and guidance to identify cases for extended re-testing, including which information should be included when referring samples to an NRL are presented. CONCLUSION: Monitoring the proportion of and reasons for failure to detect HPV in HSIL+ will help support high performance and quality improvement of HPV testing services. We encourage implementation of QA strategies based on re-analysis of "HPV negative" HSIL+ samples.

Assessment of the clinical and analytical performance of three Seegene Allplex SARS-CoV-2 assays within the VALCOR framework.

The coronavirus disease 2019 (COVID-19) pandemic demonstrated the need for accurate diagnostic testing for the early detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although the pandemic has ended, accurate assays are still needed to monitor viral spread at national levels and beyond through population and wastewater surveillance. To enhance early detection, SARS-CoV-2 assays should have high diagnostic accuracy and should be validated to assure accurate results. Three distinct SARS-CoV-2 assays were evaluated with clinical samples using the VALCOR (VALidation of SARS-CORona Virus-2 assays) framework, with the TaqPath COVID-19 assay (ThermoFisher Scientific, USA) as a comparator. We evaluated clinical sensitivity, specificity, limit of detection (LOD), and overall concordance between comparator and three index Allplex SARS-CoV-2 assays (Seegene, South Korea): Allplex-SC2, Allplex-SC2Fast (Fast PCR), and Allplex-SC2FabR (SARS-CoV-2/FluA/FluB/respiratory syncytial virus). Analytical performance and LOD of index assays were assessed using a dilution series of three synthetic SARS-CoV-2 sequence reference materials (RMs). Ninety SARS-CoV-2 positives and 90 SARS-CoV-2 negatives were tested. All Allplex assays had 100.0% sensitivity (95%CI = 95.9%-100.0%). Allplex-SC2 and Allplex-SC2Fast assays had 97.8% specificity (95%CI = 92.3%-99.7%) and 98.9% overall concordance [κ = 0.978 (95%CI = 0.947-1.000)]. Allplex-SC2FabR assay showed 100.0% specificity (95%CI = 95.9%-100.0%) and 100.0% overall concordance [κ = 1.000 (95%CI = 1.000-1.000)]. LOD assessment of index assays revealed detection down to 2.61 × 102 copies/mL in clinical samples, while the analytical LOD was 9.00 × 102 copies/mL. In conclusion, the evaluation of the three Seegene Allplex SARS-CoV-2 assays showed high sensitivity and specificity and an overall good assay concordance with the comparator. The assays showed low analytical LOD using RM and even a slightly lower LOD in clinical samples. Non-overlapping target gene sequences between SARS-CoV-2 assays and RMs emphasize the need for aligning targeted sequences of diagnostic assays and RMs.IMPORTANCEThe coronavirus disease 2019 pandemic has a significant impact on global public health, economies, and societies. As shown through the first phases of the pandemic, accurate and timely diagnosis is crucial for disease control, prevention, and monitoring. Though the pandemic phase of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has concluded, diagnostic assays remain in demand to monitor SARS-CoV-2 at the individual patient level, regionally, and nationally, as well as to remain an infectious disease preparedness instrument to monitor any new SARS-CoV-2 dissemination across borders using population and wastewater surveillance. The anticipation by WHO and central health care policy entities such as the Center for Disease Control, EMA, and multiple national health authorities is that SARS-CoV-2 will reside as an endemic respiratory disease for years to come. The key strategic consideration is hence shifting from combating a pandemic situation with a high number of patients to instead allowing precise diagnostics of suspected patients with the intention of correct management in a low-prevalence setting.

A Multifaceted Approach for Evaluating Hepatitis E Virus Infectivity In Vitro: Cell Culture and Innovative Molecular Methods for Integrity Assessment.

Hepatitis E virus is a prominent cause of viral hepatitis worldwide. In Western countries, most infections are asymptomatic. However, acute self-limiting hepatitis and chronic cases in immunocompromised individuals can occur. Studying HEV is challenging due to its difficulty to grow in cell culture. Consequently, the detection of the virus mainly relies on RT-qPCR, which cannot differentiate between infectious and non-infectious particles. To overcome this problem, methods assessing viral integrity offer a possible solution to differentiate between intact and damaged viruses. This study aims at optimizing existing HEV cell culture models and RT-qPCR-based assays for selectively detecting intact virions to establish a reliable model for assessing HEV infectivity. In conclusion, these newly developed methods hold promise for enhancing food safety by identifying approaches for inactivating HEV in food processing, thereby increasing food safety measures.

Genomic monitoring of SARS-CoV-2 variants using sentinel SARI hospital surveillance.

Background: To support the COVID-19 pandemic response, many countries, including Belgium, implemented baseline genomic surveillance (BGS) programs aiming to early detect and characterize new SARS-CoV-2 variants. In parallel, Belgium maintained a sentinel network of six hospitals that samples patients with severe acute respiratory infections (SARI) and integrated SARS-CoV-2 detection within a broader range of respiratory pathogens. We evaluate the ability of the SARI surveillance to monitor general trends and early signals of viral genetic evolution of SARS-CoV-2 and compare it with the BGS as a reference model. Methods: Nine-hundred twenty-five SARS-CoV-2 positive samples from patients fulfilling the Belgian SARI definition between January 2020 and December 2022 were sequenced using the ARTIC Network amplicon tiling approach on a MinION platform. Weekly variant of concern (VOC) proportions and types were compared to those that were circulating between 2021 and 2022, using 96,251 sequences of the BGS. Results: SARI surveillance allowed timely detection of the Omicron (BA.1, BA.2, BA.4, and BA.5) and Delta (B.1.617.2) VOCs, with no to 2 weeks delay according to the start of their epidemic growth in the Belgian population. First detection of VOCs B.1.351 and P.1 took longer, but these remained minor in Belgium. Omicron BA.3 was never detected in SARI surveillance. Timeliness could not be evaluated for B.1.1.7, being already major at the start of the study period. Conclusions: Genomic surveillance of SARS-CoV-2 using SARI sentinel surveillance has proven to accurately reflect VOCs detected in the population and provides a cost-effective solution for long-term genomic monitoring of circulating respiratory viruses.

Influenza versus other respiratory viruses - assessing severity among hospitalised children, Belgium, 2011 to 2020.

BackgroundKnowledge on the burden attributed to influenza viruses vs other respiratory viruses in children hospitalised with severe acute respiratory infections (SARI) in Belgium is limited.AimThis observational study aimed at describing the epidemiology and assessing risk factors for severe disease.MethodsWe retrospectively analysed data from routine national sentinel SARI surveillance in Belgium. Respiratory specimens collected during winter seasons 2011 to 2020 were tested by multiplex real-time quantitative PCR (RT-qPCR) for influenza and other respiratory viruses. Demographic data and risk factors were collected through questionnaires. Patients were followed-up for complications or death during hospital stay. Analysis focused on children younger than 15 years. Binomial logistic regression was used to identify risk factors for severe disease in relation to infection status.ResultsDuring the winter seasons 2011 to 2020, 2,944 specimens met the study case definition. Complications were more common in children with underlying risk factors, especially asthma (adjusted risk ratio (aRR): 1.87; 95% confidence interval (CI): 1.46-2.30) and chronic respiratory disease (aRR: 1.88; 95% CI: 1.44-2.32), regardless of infection status and age. Children infected with non-influenza respiratory viruses had a 32% higher risk of complications (aRR: 1.32; 95% CI: 1.06-1.66) compared with children with influenza only.ConclusionMulti-virus testing in children with SARI allows a more accurate assessment of the risk of complications and attribution of burden to respiratory viruses beyond influenza. Children with asthma and respiratory disease should be prioritised for clinical care, regardless of their virological test result and age, and targeted for prevention campaigns.

Hepatitis E virus in pork meat products and exposure assessment in Belgium.

Zoonotic hepatitis E virus (HEV) genotype 3 infections are the predominant cause of acute viral hepatitis in Europe, mostly associated with the consumption of HEV contaminated pork meat. In this study we looked at the HEV RNA positivity rate of pork meat products readily available from Belgian supermarkets and evaluated the overall HEV consumer exposure in a Belgian context. Two basic assessments were performed in a 'worst-case' scenario setting: one solely focusing on the contamination level of the product itself (ingredients and processing parameters) and another estimating the overall consumer exposure, taking into account consumption habits in Belgium. Non-thermal-processed ready-to-eat (i.e. ready for consumption without additional cooking step by consumer) pork meat products (e.g. raw dried sausages), had a high estimated HEV contamination level, while thermal-processed ready-to-eat pork meat products (e.g. pork liver pâté) had the highest overall consumer exposure estimates. Following these assessments, pork liver pâtés, raw dried hams and raw dried sausages (n = 54) were purchased from Belgian supermarkets (n = 3) and analyzed for HEV RNA by RT-PCR. In total, 31 % (n = 17) products tested positive. HEV RNA was found in 65 % of the pork liver pâtés, 15 % of raw dried hams and 0 % of raw dried sausages. Phylogenetic analysis of four isolates (all gt3c) from pork liver pâté samples showed similarities with human clinical cases from Germany and Belgium.

Development of Digital Droplet PCR Targeting the Influenza H3N2 Oseltamivir-Resistant E119V Mutation and Its Performance through the Use of Reverse Genetics Mutants.

The monitoring of antiviral-resistant influenza virus strains is important for public health given the availability and use of neuraminidase inhibitors and other antivirals to treat infected patients. Naturally occurring oseltamivir-resistant seasonal H3N2 influenza virus strains often carry a glutamate-to-valine substitution at position 119 in the neuraminidase (E119V-NA). Early detection of resistant influenza viruses is important for patient management and for the rapid containment of antiviral resistance. The neuraminidase inhibition assay allows the phenotypical identification of resistant strains; however, this test often has limited sensitivity with high variability depending on the virus strain, drugs and assays. Once a mutation such as E119V-NA is known, highly sensitive PCR-based genotypic assays can be used to identify the prevalence of such mutant influenza viruses in clinical samples. In this study, based on an existing reverse transcriptase real-time PCR (RT-qPCR) assay, we developed a reverse transcriptase droplet digital PCR assay (RT-ddPCR) to detect and quantify the frequency of the E119V-NA mutation. Furthermore, reverse genetics viruses carrying this mutation were created to test the performance of the RT-ddPCR assay and compare it to the standard phenotypic NA assay. We also discuss the advantage of using an RT-ddPCR instead of qPCR method in the context of viral diagnostics and surveillance.

Immunogenicity and 1-year boostability of a three-dose intramuscular rabies pre-exposure prophylaxis schedule in adults receiving immunosuppressive monotherapy: a prospective single-centre clinical trial.

BACKGROUND: For immunocompromised patients (ICPs), administration of rabies immunoglobulins (RIG) after exposure is still recommended regardless of prior vaccination, due to a lack of data. We aimed to assess the 1-year boostability of a three-dose rabies pre-exposure prophylaxis (PrEP) schedule in individuals using immunosuppressive monotherapy. METHODS: In this prospective study, individuals on immunosuppressive monotherapy with a conventional immunomodulator (cIM) or a TNF-alpha inhibitor (TNFi) for a chronic inflammatory disease received a three-dose intramuscular PrEP schedule (days 0,7,21-28) with 1 mL Rabipur®, followed by a two-dose simulated post-exposure prophylaxis (PEP) schedule (days 0,3) after 12 months. Rabies neutralizing antibodies were assessed at baseline, on day 21-28 (before the third PrEP dose), day 60, month 12 and month 12 + 7 days. The primary outcome was 1-year boostability, defined as the proportion of patients with a neutralizing antibody titre of ≥ 0.5 IU/mL at month 12 + 7 days. Secondary outcomes were geometric mean titres (GMTs) and factors associated with the primary endpoint. RESULTS: We included 56 individuals, of whom 52 completed the study. The 1-year boostability was 90% (47/52) with a GMT of 6.16 (95% CI 3.83-9.91). All participants seroconverted at some point in the study. Early response to PrEP (at day 21-28) was significantly associated with 100% boostability (Odds Ratio 51; 95% confidence interval [5.0-6956], P < 0.01). The vaccination schedule was safe and well tolerated. No vaccine-related serious adverse events occurred. CONCLUSION: In patients using immunosuppressive monotherapy, a three-dose rabies PrEP schedule followed by a two-dose PEP schedule is immunogenic, with all patients seroconverting at some point in the study. Although boostability 7 days after PEP was not 100%, nobody would wrongly be denied RIG when only administered to those who responded early to PrEP while reducing the administration of RIG by 73%.

Viral clade is associated with severity of symptomatic genotype 3 hepatitis E virus infections in Belgium, 2010-2018.

BACKGROUND & AIMS: HEV genotype (gt) 3 infections are prevalent in high-income countries and display a wide spectrum of clinical presentations. Host - but not viral - factors are reported to be associated with worse clinical outcomes. METHODS: Demographic, clinical, and biochemical data laboratory-confirmed HEV infections (by PCR and/or a combination of IgM and IgG serology) at the Belgian National Reference Centre between January 2010 and June 2018 were collected using standardised case report forms. Genotyping was based on HEV open reading frame 2 sequences. Serum CXCL10 levels were measured by a magnetic bead-based assay. H&E staining was performed on liver biopsies. RESULTS: A total of 274 HEV-infected individuals were included. Subtype assignment was possible for 179/218 viraemic cases, confirming gt3 as dominant with an almost equal representation of clades abchijklm and efg. An increased hospitalisation rate and higher peak serum levels of alanine aminotransferase, bilirubin, and alkaline phosphatase were found in clade efg-infected individuals in univariate analyses. In multivariable analyses, clade efg infections remained more strongly associated with severe disease presentation than any of the previously identified host risk factors, being associated with a 2.1-fold higher risk of hospitalisation (95% CI 1.1-4.4, p = 0.034) and a 68.2% higher peak of bilirubin levels (95% CI 13.3-149.9, p = 0.010), independently of other factors included in the model. In addition, acute clade efg infections were characterised by higher serum CXCL10 levels (p = 0.0005) and a more pronounced liver necro-inflammatory activity (p = 0.022). CONCLUSIONS: In symptomatic HEV gt3 infections, clade efg is associated with a more severe disease presentation, higher serum CXCL10 levels, and liver necro-inflammatory activity, irrespective of known host risk factors. CLINICAL TRIAL REGISTRATION: The protocol was submitted to clinicaltrials.gov (NCT04670419). IMPACT AND IMPLICATIONS: HEV genotype (gt) 3 infections display a wide spectrum of clinical presentations currently ascribed to host factors. Here we examined the role of viral factors on liver disease outcomes by combining viral phylogeny with clinical, biochemical, cytokine, and histological data from 274 Belgian adults infected with HEV presenting between 2010 and 2018. HEV gt 3 clade efg infections were associated with a more severe disease presentation, higher serum CXCL10 levels and liver necro-inflammatory activity, irrespective of known host risk factors. HEV gt3 clade-dependent clinical outcomes call for broad HEV gt3 subtyping in clinical practice and research to help identify those at higher risk for worse outcomes and to further unravel underlying virus-host interactions.

A general approach to identify low-frequency variants within influenza samples collected during routine surveillance.

Influenza viruses exhibit considerable diversity between hosts. Additionally, different quasispecies can be found within the same host. High-throughput sequencing technologies can be used to sequence a patient-derived virus population at sufficient depths to identify low-frequency variants (LFV) present in a quasispecies, but many challenges remain for reliable LFV detection because of experimental errors introduced during sample preparation and sequencing. High genomic copy numbers and extensive sequencing depths are required to differentiate false positive from real LFV, especially at low allelic frequencies (AFs). This study proposes a general approach for identifying LFV in patient-derived samples obtained during routine surveillance. Firstly, validated thresholds were determined for LFV detection, whilst balancing both the cost and feasibility of reliable LFV detection in clinical samples. Using a genetically well-defined population of influenza A viruses, thresholds of at least 104 genomes per microlitre and AF of ≥5 % were established as detection limits. Secondly, a subset of 59 retained influenza A (H3N2) samples from the 2016-2017 Belgian influenza season was composed. Thirdly, as a proof of concept for the added value of LFV for routine influenza monitoring, potential associations between patient data and whole genome sequencing data were investigated. A significant association was found between a high prevalence of LFV and disease severity. This study provides a general methodology for influenza LFV detection, which can also be adopted by other national influenza reference centres and for other viruses such as SARS-CoV-2. Additionally, this study suggests that the current relevance of LFV for routine influenza surveillance programmes might be undervalued.

Risks related to a possible reduction of the waiting period for dogs after rabies antibody titration to 30 days compared with 90 days of the current EU legislative regime.

EFSA received a mandate from the European Commission to assess the risks related to a possible reduction of the waiting period after rabies antibody titration test to 30 days compared with 90 days of the current EU legislation, for dogs moving from certain non-EU countries to the EU. This Scientific Report assessed the probability of introduction of rabies into the EU through commercial and non-commercial movements of vaccinated dogs with a positive titration test (≥ 0.5 IU/mL) if the waiting period decreases from 90 to 30 days. Assuming that all the legal requirements are complied with, the risk of transmission of rabies through the movement of a vaccinated dog is related to the risk of introducing an animal incubating rabies that was infected before the day of vaccination or shortly after vaccination but before the development of immunity (21 days post-vaccination). Using published data on the incubation period for experimental and field cases in dogs and considering the rabies incidence data in certain countries, the aggregated probability for the annual introduction of rabies through dogs was assessed. Considering the uncertainty related to the duration of the incubation period, the number of imported dogs, and the disease incidence in some countries it was concluded with a 95% certainty that the maximum number of rabies-infected imported dogs complying with the regulations in a 20-year period could increase from 5 to 20 when decreasing the waiting period from 90 to 30 days. Nevertheless, the potential impact of even a small increase in probability means the risk is increased for a region like the EU where rabies has long been a focus for eradication, to protect human and animal health.

A High-Throughput Yellow Fever Neutralization Assay.

Quick and accurate detection of neutralizing antibodies (nAbs) against yellow fever is essential in serodiagnosis during outbreaks for surveillance and to evaluate vaccine efficacy in population-wide studies. All of this requires serological assays that can process a large number of samples in a highly standardized format. Albeit being laborious, time-consuming, and limited in throughput, the classical plaque reduction neutralization test (PRNT) is still considered the gold standard for the detection and quantification of nAbs due to its sensitivity and specificity. Here, we report the development of an alternative fluorescence-based serological assay (SNTFLUO) with an equally high sensitivity and specificity that is fit for high-throughput testing with the potential for automation. Finally, our novel SNTFLUO was cross-validated in several reference laboratories and against international WHO standards, showing its potential to be implemented in clinical use. SNTFLUO assays with similar performance are available for the Japanese encephalitis, Zika, and dengue viruses amenable to differential diagnostics. IMPORTANCE Fast and accurate detection of neutralizing antibodies (nAbs) against yellow fever virus (YFV) is key in yellow fever serodiagnosis, outbreak surveillance, and monitoring of vaccine efficacy. Although classical PRNT remains the gold standard for measuring YFV nAbs, this methodology suffers from inherent limitations such as low throughput and overall high labor intensity. We present a novel fluorescence-based serum neutralization test (SNTFLUO) with equally high sensitivity and specificity that is fit for processing a large number of samples in a highly standardized manner and has the potential to be implemented for clinical use. In addition, we present SNTFLUO assays with similar performance for Japanese encephalitis, Zika, and dengue viruses, opening new avenues for differential diagnostics.

Whole-Genome Sequence Approach and Phylogenomic Stratification Improve the Association Analysis of Mutations With Patient Data in Influenza Surveillance.

Each year, seasonal influenza results in high mortality and morbidity. The current classification of circulating influenza viruses is mainly focused on the hemagglutinin gene. Whole-genome sequencing (WGS) enables tracking mutations across all influenza segments allowing a better understanding of the epidemiological effects of intra- and inter-seasonal evolutionary dynamics, and exploring potential associations between mutations across the viral genome and patient's clinical data. In this study, mutations were identified in 253 Influenza A (H3N2) clinical isolates from the 2016-2017 influenza season in Belgium. As a proof of concept, available patient data were integrated with this genomic data, resulting in statistically significant associations that could be relevant to improve the vaccine and clinical management of infected patients. Several mutations were significantly associated with the sampling period. A new approach was proposed for exploring mutational effects in highly diverse Influenza A (H3N2) strains through considering the viral genetic background by using phylogenetic classification to stratify the samples. This resulted in several mutations that were significantly associated with patients suffering from renal insufficiency. This study demonstrates the usefulness of using WGS data for tracking mutations across the complete genome and linking these to patient data, and illustrates the importance of accounting for the viral genetic background in association studies. A limitation of this association study, especially when analyzing stratified groups, relates to the number of samples, especially in the context of national surveillance of small countries. Therefore, we investigated if international databases like GISAID may help to verify whether observed associations in the Belgium A (H3N2) samples, could be extrapolated to a global level. This work highlights the need to construct international databases with both information of viral genome sequences and patient data.

No molecular detection of tick-borne pathogens in the blood of patients with erythema migrans in Belgium.

BACKGROUND: A number of tick-borne pathogens circulate in the Belgian tick population in addition to the causative agent of Lyme borreliosis. However, so far, only a few patients with tick-borne diseases other than Lyme borreliosis have been reported in Belgium. The aim of this study was to investigate the occurrence of other human tick-borne infections in Belgium and their possible clinical manifestation. METHODS: Patients with fever (> 37.5 °C) after a tick bite or those with erythema migrans (EM) were included in the study. EDTA-blood samples were screened for the presence of DNA from Borrelia burgdorferi sensu lato, Borrelia miyamotoi, Anaplasma phagocytophilum, Neoehrlichia mikurensis, spotted fever group rickettsiae (genus Rickettsia), Babesia spp., Bartonella spp., Spiroplasma ixodetis and tick-borne encephalitis virus, using multiplex PCR methods. A questionnaire on, among others, demographics and clinical symptoms, was also filled in. RESULTS: Over a period of 3 years, 119 patients with EM and 14 patients with fever after a recent tick bite were enrolled in the study. Three samples initially tested positive for N. mikurensis by quantitative PCR (qPCR), but the results could not be confirmed by other PCR methods, and repetition of the DNA extraction procedure and qPCR test was not successful. The qPCR test results for the other tick-borne pathogens were negative. CONCLUSIONS: In general, only a few patients with fever after a tick bite could be identified. Although no tick-borne pathogens were detected, their occurrence cannot be excluded based on the limited number of patients and the limitations inherent to current methodologies. This study underscores the possibility of false-positive PCR results and the necessity for the development of multiple independent tools for the sensitive and specific detection of emerging tick-borne pathogens.

Evaluation of dog vaccination schemes against rabies in Kinshasa, Democratic Republic of the Congo.

The traditional rabies control strategy based on annual mass vaccination of dogs appears to be costly and cumbersome. Given the existence of different risk zones for rabies transmission, the present study aimed at proposing risk-based vaccination schemes by considering canine population dynamics as well as vaccine efficacy and duration of immunity (DOI). The capital of the Democratic Republic of the Congo (RDC), Kinshasa, was chosen as study site. The turnover rate of dogs was used to assess their population dynamics in two low-roaming (<25 % of dogs are roaming) and in two high-roaming zones (>75 % of dogs are roaming). The sero-conversion rate was assessed in response to primo-vaccination in three age groups: 24 puppies (≤3months), 37 juveniles (4-12 months) and 22 adult dogs. The DOI was evaluated serologically by revaccinating dogs previously vaccinated since 1-2 years (n = 31), 2-3 years (n = 12) or 3-7.5 years (n = 4). Rapid Fluorescent Focus Inhibition Test was used to quantify antibodies. These data were used to implement vaccination outcome models.The turnover rate was twice as high in high-roaming zones (36 %) as that in lowroaming zones (17 %). Irrespective of roaming level, 75 % of dogs were less than 3 years old. The vaccine was equally effective in puppies (96 %), juvenile (97 %) and adult dogs (100 %, p = 0.24). The vaccine was effective in 93 % (11/12) of puppies without pre-vaccinal protective titers (≥0.5 IU/mL). The anamnestic response was strong within 5-8 days upon the booster vaccination, in 96 % (45/47) of dogs reported vaccinated 1-7.5 years before. This suggests that the vaccine provided a long-term protection (≥3 years) which is likely to occur in 75 % of dogs in Kinshasa.Hypothesizing a vaccination stop, the vaccination outcome model allowed to estimate the time point after which vaccination coverage would drop below 40 % in function of dog population turnover rate. The systematic vaccination of puppies as well as annual vaccination of dogs aged between 3 and 15 months or annual vaccination of all unvaccinated dogs aged more than 3 months of age appeared as valuable alternative to systematic annual mass vaccination.In conclusion, this study developed a vaccination outcome model pointing out the impact of dog population dynamics and of effective duration of immunity. It appears as a promising tool for designing cost-effective rabies vaccination campaigns.

Long-term Memory Response After a Single Intramuscular Rabies Booster Vaccination 10-24 Years After Primary Immunization.

BACKGROUND: Published data regarding long-lasting immunological rabies memory after pre-exposure prophylaxis (PrEP) are scarce. We tested the hypothesis that rabies booster immunization elicits rapid anamnestic responses. METHODS: For this observational study, we included participants who had received PrEP 10-24 years before inclusion. We measured rabies antibody titers before, and on days 3, 7, and 14 after a single intramuscular booster. RESULTS: All 28 participants responded adequately regardless of route of administration or 2-dose vs 3-dose PrEP regimen. CONCLUSION: Rabies immunological memory is reactivated within 7 days after a single intramuscular booster immunization, even when administered 10-24 years after PrEP.

Poor Antibody Response to BioNTech/Pfizer Coronavirus Disease 2019 Vaccination in Severe Acute Respiratory Syndrome Coronavirus 2-Naive Residents of Nursing Homes.

BACKGROUND: Residents of nursing homes (NHs) are at high risk of coronavirus disease 2019 (COVID-19)-related disease and death and may respond poorly to vaccination because of old age and frequent comorbid conditions. METHODS: Seventy-eight residents and 106 staff members, naive to infection or previously infected with severe acute respiratory syndrome coronavirus (SARS-CoV-2), were recruited in NHs in Belgium before immunization with 2 doses of 30 µg BNT162b2 messenger RNA (mRNA) vaccine at days 0 and 21. Binding antibodies (Abs) to SARS-CoV-2 receptor-binding domain (RBD), spike domains S1 and S2, RBD Ab avidity, and neutralizing Abs against SARS-CoV-2 wild type and B.1.351 were assessed at days 0, 21, 28, and 49. RESULTS: SARS-CoV-2-naive residents had lower Ab responses to BNT162b2 mRNA vaccination than naive staff. These poor responses involved lower levels of immunoglobulin (Ig) G to all spike domains, lower avidity of RBD IgG, and lower levels of Abs neutralizing the vaccine strain. No naive residents had detectable neutralizing Abs to the B.1.351 variant. In contrast, SARS-CoV-2-infected residents had high responses to mRNA vaccination, with Ab levels comparable to those in infected staff. Cluster analysis revealed that poor vaccine responders included not only naive residents but also naive staff, emphasizing the heterogeneity of responses to mRNA vaccination in the general population. CONCLUSIONS: The poor Ab responses to mRNA vaccination observed in infection-naive NH residents and in some naive staff members suggest suboptimal protection against breakthrough infection, especially with variants of concern. These data support the administration of a third dose of mRNA vaccine to further improve protection of NH residents against COVID-19.

Safety and immunogenicity of a reduced dose of the BNT162b2 mRNA COVID-19 vaccine (REDU-VAC): A single blind, randomized, non-inferiority trial.

Fractional dosing of COVID-19 vaccines could accelerate vaccination rates in low-income countries. Dose-finding studies of the mRNA vaccine BNT162b2 (Pfizer-BioNTech) suggest that a fractional dose induces comparable antibody responses to the full dose in people <55 years. Here, we report the safety and immunogenicity of a fractional dose regimen of the BNT162b2 vaccine. REDU-VAC is a participant-blinded, randomised, phase 4, non-inferiority study. Adults 18-55 years old, either previously infected or infection naïve, were randomly assigned to receive 20µg/20µg (fractional dose) or 30µg/30µg (full dose) of BNT162b2. The primary endpoint was the geometric mean ratio (GMR) of SARS-CoV-2 anti-RBD IgG titres at 28 days post second dose between the reduced and full dose regimens. The reduced dose was considered non-inferior to the full dose if the lower limit of the two-sided 95% CI of the GMR was >0.67. Primary analysis was done on the per-protocol population, including infection naïve participants only. 145 participants were enrolled and randomized, were mostly female (69.5%), of European origin (95%), with a mean age of 40.4 years (SD 7.9). At 28 days post second dose, the geometric mean titre (GMT) of anti-RBD IgG of the reduced dose regimen (1,705 BAU/mL) was not non-inferior to the full dose regimen (2,387 BAU/mL), with a GMR of 0.714 (two-sided 95% CI 0.540-0.944). No serious adverse events occurred. While non-inferiority of the reduced dose regimen was not demonstrated, the anti-RBD IgG titre was only moderately lower than that of the full dose regimen and, importantly, still markedly higher than the reported antibody response to the licensed adenoviral vector vaccines. These data suggest that reduced doses of the BNT162b2 mRNA vaccine may offer additional benefit as compared to the vaccines currently in use in most low and middle-income countries, warranting larger immunogenicity and effectiveness trials. Trial Registration: The trial is registered at ClinicalTrials.gov (NCT04852861).

Spotlight influenza: Extending influenza surveillance to detect non-influenza respiratory viruses of public health relevance: analysis of surveillance data, Belgium, 2015 to 2019.

BackgroundSeasonal influenza-like illness (ILI) affects millions of people yearly. Severe acute respiratory infections (SARI), mainly influenza, are a leading cause of hospitalisation and mortality. Increasing evidence indicates that non-influenza respiratory viruses (NIRV) also contribute to the burden of SARI. In Belgium, SARI surveillance by a network of sentinel hospitals has been ongoing since 2011.AimWe report the results of using in-house multiplex qPCR for the detection of a flexible panel of viruses in respiratory ILI and SARI samples and the estimated incidence rates of SARI associated with each virus.MethodsWe defined ILI as an illness with onset of fever and cough or dyspnoea. SARI was defined as an illness requiring hospitalisation with onset of fever and cough or dyspnoea within the previous 10 days. Samples were collected in four winter seasons and tested by multiplex qPCR for influenza virus and NIRV. Using catchment population estimates, we calculated incidence rates of SARI associated with each virus.ResultsOne third of the SARI cases were positive for NIRV, reaching 49.4% among children younger than 15 years. In children younger than 5 years, incidence rates of NIRV-associated SARI were twice that of influenza (103.5 vs 57.6/100,000 person-months); co-infections with several NIRV, respiratory syncytial viruses, human metapneumoviruses and picornaviruses contributed most (33.1, 13.6, 15.8 and 18.2/100,000 person-months, respectively).ConclusionEarly testing for NIRV could be beneficial to clinical management of SARI patients, especially in children younger than 5 years, for whom the burden of NIRV-associated disease exceeds that of influenza.