Influence of the Delta Variant and Vaccination on the SARS-CoV-2 Viral Load

Studies comparing SARS-CoV-2 nasopharyngeal (NP) viral load (VL) according to virus variant and host vaccination status have yielded inconsistent results. We conducted a single center prospective study between July and September 2021 at the drive-through testing center of the Toulouse University Hospital. We compared the NP VL of 3775 patients infected by the Delta (n = 3637) and Alpha (n = 138) variants, respectively. Patient’s symptoms and vaccination status (2619 unvaccinated, 636 one dose and 520 two doses) were recorded. SARS-CoV-2 RNA testing and variant screening were assessed by using Thermo Fisher® TaqPath™ COVID-19 and ID solutions® ID™ SARS-CoV-2/VOC evolution Pentaplex assays. Delta SARS-CoV-2 infections were associated with higher VL than Alpha (coef = 0.68; p ≤ 0.01) independently of patient’s vaccination status, symptoms, age and sex. This difference was higher for patients diagnosed late after symptom onset (coef = 0.88; p = 0.01) than for those diagnosed early (coef = 0.43; p = 0.03). Infections in vaccinated patients were associated with lower VL (coef = −0.18; p ≤ 0.01) independently of virus variant, symptom, age and sex. Our results suggest that Delta infections could lead to higher VL and for a longer period compared to Alpha infections. By effectively reducing the NP VL, vaccination could allow for limiting viral spread, even with the Delta variant

Hepatitis A: Epidemiology, High-Risk Groups, Prevention and Research on Antiviral Treatment

International audienceThe hepatitis A virus (HAV) is a leading cause of acute viral hepatitis worldwide. It is transmitted mainly by direct contact with patients who have been infected or by ingesting contaminated water or food. The virus is endemic in low-income countries where sanitary and sociodemographic conditions are poor. Paradoxically, improving sanitary conditions in these countries, which reduces the incidence of HAV infections, can lead to more severe disease in susceptible adults. The populations of developed countries are highly susceptible to HAV, and large outbreaks can occur when the virus is spread by globalization and by increased travel and movement of foodstuffs. Most of these outbreaks occur among high-risk groups: travellers, men who have sex with men, people who use substances, and people facing homelessness. Hepatitis A infections can be prevented by vaccination; safe and effective vaccines have been available for decades. Several countries have successfully introduced universal mass vaccination for children, but high-risk groups in high-income countries remain insufficiently protected. The development of HAV antivirals may be important to control HAV outbreaks in developed countries where a universal vaccination programme is not recommended

Will the latest wave of the COVID‐19 pandemic be an ecological disaster? There is an urgent need to replace plastic by ecologically virtuous materials

Abstract Background and Aims Direct virological diagnosis of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS‐CoV‐2) infectionis based on either viral antigen or viral genome detection. These methods, in addition to the dedicated reagents and transport packaging, require the use of quantities of plastic that may individually appear negligible but which, in the context of a pandemic, are very high. The aim was to estimate the amount of plastic involved in a diagnostic assay whether molecular or antigenic. Methods We weighed the plastics used to obtain a diagnostic assay result for SARS‐CoV‐2 infection in our hospital. Results Each ready‐to‐use antigen assay requires about 20 g of plastic whereas the PCR assay implies the use of 30 g. This unit mass, when compared to our laboratory's SARS‐CoV‐2 genomic screening activity,represents more than 10 tons of plastic for 2021. At our region level (#6.10 inhabitants), more than 350 tons of plastic were used to carry out more than 7 million declared PCR assays and as many antigenic assays. Conclusions The virologic diagnostic activityl inked to the SARS‐CoV‐2 pandemic has highlighted once more our dependance for plastic use. We must already think about a more environmentally virtuous diagnostic activity by integrating a reasonned use of diagnostic tools and a higher use of ecological friendly material. Parallel the notion of waste management must also be addressed in order to limit their environmental impact

Hepatitis E Virus: How It Escapes Host Innate Immunity

International audienceHepatitis E virus (HEV) is a leading cause of viral hepatitis in the world. It is usually responsible for acute hepatitis, but can lead to a chronic infection in immunocompromised patients. The host's innate immune response is the first line of defense against a virus infection; there is growing evidence that HEV RNA is recognized by toll-like receptors (TLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), leading to interferon (IFN) production. The IFNs activate interferon-stimulated genes (ISGs) to limit HEV replication and spread. HEV has developed strategies to counteract this antiviral response, by limiting IFN induction and signaling. This review summarizes the advances in our knowledge of intracellular pathogen recognition, interferon and inflammatory response, and the role of virus protein in immune evasion

Vectorial Release of Human RNA Viruses from Epithelial Cells

International audienceEpithelial cells are apico-basolateral polarized cells that line all tubular organs and are often targets for infectious agents. This review focuses on the release of human RNA virus particles from both sides of polarized human cells grown on transwells. Most viruses that infect the mucosa leave their host cells mainly via the apical side while basolateral release is linked to virus propagation within the host. Viruses do this by hijacking the cellular factors involved in polarization and trafficking. Thus, understanding epithelial polarization is essential for a clear understanding of virus pathophysiology

Antibody Titers and Protection against Omicron (BA.1 and BA.2) SARS-CoV-2 Infection

The emergence of the SARS-CoV-2 variants of concern has greatly influenced the immune correlates of protection, and there are little data about the antibody threshold concentrations to protect against infection with SARS-CoV-2 Omicron BA.1 or BA.2. We analyzed the antibody responses of 259 vaccinated healthcare workers, some of whom had been previously infected by SARS-CoV-2. The median follow-up was 179 days (IQR: 171–182) after blood collection. We detected 88 SARS-CoV-2 Omicron infections during the follow-up period, 55 (62.5%) with SARS-CoV-2 BA.1, and 33 (37.5%) with SARS-CoV-2 BA.2. A neutralizing antibody titer below 8 provided no protection against a BA.1 infection, a titer of 16 or 32 gave 73.2% protection, and a titer of 64 or 128 provided 78.4% protection. Conversely, the BA.2 infection rate did not vary as a function of anti-BA.2 neutralizing antibody titers. Binding antibody concentrations below 6000 BAU/mL provided no protection against Omicron BA.1 infection, 6000–20,000 BAU/mL provided 55.6% protection, and 20,000 or more provided 87.7% protection. There was no difference in BA.2 infection depending on the binding antibody concentration. Further studies are needed to investigate the relationship between antibody concentrations and infection with the Omicron BA.4/5 variants that are becoming predominant worldwide

Hepatitis E virus infections in Europe

International audienceHepatitis E virus (HEV) is the most common cause of acute viral hepatitis worldwide. The systematic use of improved tools for diagnosing and genotyping has completely changed our understanding of the epidemiology and clinical consequences of HEV infection. Most cases of HEV in Europe arise from infected animals such as pigs, wild boar, deer and rabbits. Zoonotic HEV genotypes (HEV genotypes 3-8) are mainly food-borne or transmitted by direct contact, but recent data suggest that infection can also be water-borne or even iatrogenic throught contamined blood products. HEV-3 is the most prevalent genotype in Europe but the geographic distributions of the 3 major clades and subgenotypes (HEV-3abjkchi, HEV-3efg, and HEV-3ra) differ. Most HEV-3 infections are asymptomatic but they can result in severe acute hepatitis in patients with chronic liver disease, chronic hepatitis in immunocompromised patients, and to extra-hepatic manifestations. Despite more frequent reports of symptomatic hepatitis E cases across Europe, systems for monitoring HEV infections vary greatly. Severe HEV-associated illnesses, hospitalizations and deaths are probably underestimated. The seroprevalence and incidence of locally acquired hepatitis E varies between and within European countries and over time. The precise origin of these variations is uncertain but may be linked to environmental factors or the degree to which HEV contaminates the human food chain. Collaborative initiatives such as the establishment of the One Health platform for HEV sequences (HEVnet database) will be very useful for a better understanding of the epidemiology of HEV in Europe and the development of effective prevention strategies

Rotavirus meningitis in an adult with transient aphasia

International audienceWe identified an additional case of documented Rotavirus meningitis in an adult with full medical history. A previously healthy 37-year-old patient presented herself for transient aphasia associated with fever and headaches at the end of a one-week history of gastroenteritis. Cerebrospinal fluid (CSF) analysis revealed lymphocytic meningitis, and treatment with aciclovir was initiated. Rotavirus A reverse transcription-polymerase chain reaction (RT-PCR) was positive in CSF and the patient's stools in favor of Rotavirus meningitis. Testing for other viruses was negative. Magnetic resonance imaging (MRI) showed no signs of encephalitis. Aphasia was resolutive in less than 12 hours, and no neurological symptoms relapsed. All symptoms evolved favorably despite aciclovir discontinuation.Viral sequencing methods have recently identified unexpected viruses as potential causative agents in meningitis, including Rotavirus. We confirm the detectability of Rotavirus in the analysis of CSF in the context of Rotavirus gastroenteritis in an adult. This case suggests postviral headache and neurological deficits with cerebrospinal fluid lymphocytosis (HaNDL) syndrome may be linked to previously undetected direct viral infection of the central nervous system.Therefore, clinicians should consider Rotavirus meningitis in diagnosing meningitis associated with gastroenteritis in adults

Influence of immune escape and nasopharyngeal virus load on the spread of SARS-CoV-2 Omicron variant

International audienceWe read with interest the letter published recently by Costa et al. in the journal of Infection. They analyzed the difference between the viral loads of the SARS-CoV-2 Alpha and Delta variants using the parameters of clinical presentation, time to testing from symptoms onset, age and vaccination status.1 A new variant of concern (VOC), the Omicron variant (B.1.1.529), emerged in South Africa in November 2021, and rapidly spread throughout the world.2 Recent data suggest that this variant is more transmissible,3 less sensitive to vaccination,4 and causes less severe outcomes than the Delta variant.5 In vitro studies have demonstrated changes in cell entry and cellular tropism with the Omicron variant that might explain its greater transmissibility and reduced severity.6,7 However, clinical data comparing Delta and Omicron infections remain scarce, especially for ambulatory patients. We therefore examined the virological features of these two variants found in patients attending testing center

Saliva sampling for diagnosing SARS-CoV-2 infections in symptomatic patients and asymptomatic carriers

International audienceIn a recent review of laboratory tests for diagnosing SARS-CoV-2 infection, Zheng et al. concluded that the detection rate of real-time quantitative PCR was lower than that of computed tomography [1]. But the authors did not discuss the possibility of using saliva sampling. Nasopharyngeal (NP) swabs are the preferred collection vehicles in France and many other countries and several studies have indicated that this method is more sensitive than sampling other sites [2–4]. Saliva sampling is less invasive for patients, less hazardous for health care workers, requires fewer experimented staff and is less expensive for mass testing. However, little is known about any differences in the sensitivities of saliva and NP sampling or how any differences vary with presence or absence of clinical symptom