Temporal dynamics of RSV shedding and genetic diversity in adults during the COVID-19 pandemic in a French hospital, early 2021.

Human respiratory syncytial virus (RSV) is responsible of lower respiratory tract infections which may be severe in infants, elderly and immunocompromised adults. Europe and North-American countries have observed a massive reduction of RSV incidence during the 2020-2021 winter season. Using a systematic RSV detection coupled to SARS-CoV-2 for all adult patients admitted at the Foch hospital (Suresnes, France) between January and March 2021 (n = 11,324), only eight RSV infections in patients with prolonged RNA shedding were diagnosed. RSV whole-genome sequencing revealed that six and two patients were infected by RSV groups A and B, respectively. RSV carriage lasted from 7 to at least 30 days disregarding of RSV lineage. The most prolonged RSV shedding was observed in an asymptomatic patient. We detected novel patient-specific non-synonymous mutations in the G glycoprotein gene, including a double identical mutation in the repeated region for one patient. No additional mutation occurred in the RSV genome over the course of infection in the four patients tested for. In conclusion, our results suggest that the temporal shift in the RSV epidemic is not likely to be explained by the emergence of a high frequency, unreported variant. Moreover, prolonged RSV carriages in asymptomatic patients could play a role in virus spread.

Earlier In Vitro Viral Production With SARS-CoV-2 Alpha Than With Beta, Gamma, B, or A.27 Variants.

Since its emergence in China at the end of 2019, SARS-CoV-2 has rapidly spread across the world to become a global public health emergency. Since then, the pandemic has evolved with the large worldwide emergence of new variants, such as the Alpha (B.1.1.7 variant), Beta (B.1.351 variant), and Gamma (P.1 variant), and some other under investigation such as the A.27 in France. Many studies are focusing on antibody neutralisation changes according to the spike mutations, but to date, little is known regarding their respective replication capacities. In this work, we demonstrate that the Alpha variant provides an earlier replication in vitro, on Vero E6 and A549 cells, than Beta, Gamma, A.27, and historical lineages. This earlier replication was associated with higher infectious titres in cell-culture supernatants, in line with the higher viral loads observed among Alpha-infected patients. Interestingly, Beta and Gamma variants presented similar kinetic and viral load than the other non-Alpha-tested variants.

Efficacy of Severe Acute Respiratory Syndrome Coronavirus-2 Vaccine in Patients With Thoracic Cancer: A Prospective Study Supporting a Third Dose in Patients With Minimal Serologic Response After Two Vaccine Doses.

INTRODUCTION: Coronavirus disease 2019 resulted in a 30% mortality rate in patients with thoracic cancer. Given that patients with cancer were excluded from serum antisevere acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccine registration trials, it is still unknown whether they would develop a protective antispike antibody response after vaccination. This prospective vaccine monitoring study primarily aimed to assess humoral responses to the SARS-CoV-2 vaccine in patients with thoracic cancer. METHODS: SARS-CoV-2-spike antibodies were measured using the Abbot Architect SARS-CoV-2 immunoglobulin G immunoassay before the first injection of BNT162b2 mRNA vaccine, at week 4, and 2 to 16 weeks after the second vaccine dose administration. The factors associated with antibody response were analyzed. RESULTS: Overall, 306 patients, with a median age of 67.0 years (interquartile range: 58-74), were vaccinated. Of these, 283 patients received two vaccine doses at 28-day intervals. After a 6.7-month median follow-up, eight patients (2.6%) contracted proven symptomatic SARS-CoV-2 infection, with rapid favorable evolution. Of the 269 serologic results available beyond day 14 after the second vaccine dose administration, 17 patients (6.3%) were still negative (<50 arbitrary units/mL, whereas 34 (11%) were less than 300 arbitrary units/mL (12.5th percentile). In multivariate analysis, only age (p < 0.01) and long-term corticosteroid treatment (p = 0.01) were significantly associated with a lack of immunization. A total of 30 patients received a third vaccine dose, with only three patients showing persistently negative serology thereafter, whereas the others exhibited clear seroconversion. CONCLUSIONS: SARS-CoV2 vaccines were found to be efficient in patients with thoracic cancer, most of them being immunized after two doses. A third shot given to 1% of patients with persistent low antibody titers resulted in an 88% immunization rate.

Humoral Response Induced by Prime-Boost Vaccination with the ChAdOx1 nCoV-19 and mRNA BNT162b2 Vaccines in a Teriflunomide-Treated Multiple Sclerosis Patient.

Patients with multiple sclerosis (MS) are treated with drugs that may impact immune responses to SARS-CoV-2 vaccination. Evaluation of "prime-boost" (heterologous) vaccination regimens including a first administration of a viral vector-based vaccine and a second one of an mRNA-based vaccine in such patients has not yet been completed. Here, we present the anti-spike protein S humoral response, including the neutralizing antibody response, in a 54-year-old MS patient who had been treated with teriflunomide for the past 2 years and who received a heterologous ChAdOx1 nCoV-19/ BNT162b2 vaccination regimen. The results showed a very strong anti-S IgG response and a good neutralizing antibody response. These results show that teriflunomide did not prevent the development of a satisfactory humoral response in this MS patient after vaccination with a ChAdOx1 nCoV-19/ BNT162b2 prime-boost protocol.

Impact of Low-Dose Methotrexate-Adalimumab Combination Therapy on the Antibody Response Induced by the mRNA-1273 SARS-CoV-2 Vaccine: Case of an Elderly Patient with Rheumatoid Arthritis.

Patients with rheumatoid arthritis (RA) are treated with drugs that may impact their immune responses to SARS-CoV-2 vaccines. We describe here the anti-Spike (anti-S) IgG and neutralizing antibody responses induced by the mRNA-1273 SARS-CoV-2 vaccine in a 78-years-old patient with RA, who received a low-dose combination therapy of methotrexate and adalimumab, shortly before vaccine administration. Both near-normal and impaired immune responses to vaccines have been reported previously in patients treated with these drugs. Our case report shows that, even at low doses, combined methotrexate-adalimumab therapy can be associated with a weak immune response to the mRNA1273 vaccine in elderly patients.

High-sensitivity SARS-CoV-2 group testing by digital PCR among symptomatic patients in hospital settings.

BACKGROUND: Worldwide demand for SARS-CoV-2 RT-PCR testing is still high as testing remains central to follow the disease spread and vaccine efficacy. Group testing has been proposed as a solution to expand testing capabilities but sensitivity concerns may limit its impact on the management of the pandemic. Digital PCR (RT-dPCR) has been shown to be highly sensitive and could help by providing larger testing capabilities without compromising sensitivity. METHODS: We implemented RT-dPCR based COVID-19 group testing on a commercially available system and assay (naica® system from Stilla Technologies) and investigated the sensitivity of the method in real life conditions of a university hospital in Paris, France, in May 2020. We tested the protocol in a direct comparison with reference RT-PCR testing on 448 samples split into groups of 8, 16 and 32 samples for RT-dPCR analysis. RESULTS: Individual RT-PCR testing identified 25/448 positive samples. Using 56 groups of 8, RT-dPCR identified 23 groups as positive, corresponding to 26 positive samples by individual PCR (positive percentage agreement 95.2% [95% confidence interval: 76.2-99.9%]) and including 2 samples not detected by individual RT-PCR but confirmed positive by further investigation. 15 of 28 groups of 16 tested positive, corresponding to 25 positive samples by individual PCR (positive percentage agreement 87.5% [95% confidence interval: 61.7-98.4%]). 14 groups of 32 were fully concordant with individual PCR testing but will need to be confirmed on larger datasets. CONCLUSIONS: Our proposed approach of group testing by digital PCR has similar diagnostic sensitivity compared to individual RT-PCR testing for group up to 16 samples. This approach reduces the quantity of reagent needed by up to 80% while reducing costs and increasing capabilities of testing up to 10-fold.

Evaluation of three extraction-free SARS-CoV-2 RT-PCR assays: A feasible alternative approach with low technical requirements.

The worldwide demand for SARS-CoV-2 RT-PCR testing resulted in a shortage of diagnostic kits. RNA extraction step constitutes a major bottleneck to perform diagnostic. The aim of this study was to assess performances of different extraction-free SARS-CoV-2 RT-PCR assays compared to a reference RT-PCR assay. The panel of evaluation consisted of 94 samples: 69 positive and 25 negative for SARS-CoV-2 by reference RT-PCR. Three extraction-free RT-PCR assays were assessed: (i) PrimeDirect® Probe RT-qPCR Mix (Takara), (ii) PrimeScript®RT-PCR (Takara), and (iii) SARS-CoV-2 SANSURE®BIOTECH Novel Coronavirus (Sansure). The overall sensitivity of PrimeDirect, PrimeScript and Sansure assays was 55.1 %, 69.6 % and 69.6 %, respectively. The sensitivity increased among samples with Ct<30: 91.9 % (n = 34/37), 89.2 % (n = 33/37) and 94.6 % (n = 35/37) for PrimeDirect, PrimeScript and Sansure assays, respectively. The specificity was 88 %, 100 % and 100 % for PrimeDirect, PrimeScript and Sansure assays, respectively. In the present study, we showed a good sensitivity of extraction-free PCR assays, especially for high viral loads (Ct<30), except PrimeDirect that displayed imperfect sensitivity and specificity. Despite a lower sensitivity for low viral loads, extraction-free reagents can provide a valuable option, cheaper, easier and less reagent consuming for SARS-CoV-2 diagnostic, especially in laboratory with lower experience and equipment for molecular assays.

Evaluation of the QIAstat-Dx Respiratory SARS-CoV-2 Panel, the First Rapid Multiplex PCR Commercial Assay for SARS-CoV-2 Detection.

In the race to contain severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), efficient detection and triage of infected patients must rely on rapid and reliable testing. In this work, we performed the first evaluation of the QIAstat-Dx respiratory SARS-CoV-2 panel (QIAstat-SARS) for SARS-CoV-2 detection. This assay is the first rapid multiplex PCR (mPCR) assay, including SARS-CoV-2 detection, and is fully compatible with a non-PCR-trained laboratory or point-of-care (PoC) testing. This evaluation was performed using 69 primary clinical samples (66 nasopharyngeal swabs [NPS], 1 bronchoalveolar lavage fluid sample [BAL], 1 tracheal aspirate sample, and 1 bronchial aspirate sample) comparing SARS-CoV-2 detection with the currently WHO-recommended reverse transcription-PCR (RT-PCR) (WHO-RT-PCR) workflow. Additionally, a comparative limit of detection (LoD) assessment was performed for QIAstat-SARS and WHO-RT-PCR using a quantified clinical sample. Compatibility of sample pretreatment for viral neutralization or viscous samples with the QIAstat-SARS system were also tested. The QIAstat-Dx respiratory SARS-CoV-2 panel demonstrated a sensitivity comparable to that of the WHO-recommended assay with a limit of detection at 1,000 copies/ml. The overall percent agreement between QIAstat-Dx SARS and WHO-RT-PCR on 69 clinical samples was 97% with a sensitivity of 100% (40/40) and specificity at 93% (27/29). No cross-reaction was encountered for any other respiratory viruses or bacteria included in the panel. The QIAstat-SARS rapid multiplex PCR panel provides a highly sensitive, robust, and accurate assay for rapid detection of SARS-CoV-2. This assay allows rapid decisions even in non-PCR-trained laboratory or point-of-care testing, allowing innovative organization.

Evaluation of the RealStar® SARS-CoV-2 RT-PCR kit RUO performances and limit of detection.

BACKGROUND: The use of efficient, reliable and sensitive PCR assays is a cornerstone in the race to contain the SARS-CoV-2 pandemic. In this work we performed an independent evaluation of the RealStar® SARS-CoV-2 RT-PCR Kit Researh Use Only (Altona) for SARS-CoV-2 detection. METHODS: A comparative limit of detection (LoD) assessment was performed between RealStar® SARS-CoV-2 and the currently WHO recommended RT-PCR (WHO-PCR) workflow using a quantified clinical sample. Assessment of the RealStar® SARS-CoV-2 assay was also performed using 83 primary clinical samples in comparison with the WHO-PCR. RESULTS: The RealStar® SARS-CoV-2 demonstrated a slightly higher sensitivity than the WHO recommended assay with a limit of detection at 625 copies/mL instead of 1250 copies/mL for the WHO-PCR in our conditions. The overall percent agreement between RealStar® SARS-CoV-2 and WHO-PCR on 83 clinical samples was 97.6 % (81/83) with a sensitivity at 97.8 % (45/46) and specificity at 97.3 % (36/37). No cross reaction was encountered for the other human coronaviruses (HKU1, OC43, NL63, 229E). CONCLUSIONS: In this comparison of the RealStar® SARS-CoV-2 assay with the reference WHO assay, we observed a slightly better sensitivity of the RealStar® assay. It provides a robust option for all molecular biology laboratories, with a strong real-life LoD and is compatible with various real-time PCR platforms.