ABSTRACT
We report the levels of neutralising antibodies against Wuhan, Delta and Omicron variants in healthy individuals pre-infected or not with SARS-CoV-2 and immunized with three doses of the BNT162b2 vaccine. Our observations support the rapid administration of a booster vaccine dose to prevent infection and disease caused by Omicron.
ABSTRACT
Background: SARS-CoV-2 human-to-animal transmission can lead to the establishment of novel reservoirs and the evolution of new variants with the potential to start new outbreaks in humans. Aim: We tested Norway rats inhabiting the sewer system of Antwerp, Belgium, for the presence of SARS-CoV-2 following a local COVID-19 epidemic peak. In addition, we discuss the use and interpretation of SARS-CoV-2 serological tests on non-human samples. Methods: Between November and December 2020, Norway rat oral swabs, feces and tissues from the sewer system of Antwerp were collected to be tested by RT-qPCR for the presence of SARS-CoV-2. Serum samples were screened for the presence of anti-SARS-CoV-2 IgG antibodies using a Luminex microsphere immunoassay (MIA). Samples considered positive were then checked for neutralizing antibodies using a conventional viral neutralization test (cVNT). Results: The serum of 35 rats was tested by MIA showing 3 potentially positive sera that were later shown to be negative by cVNT. All tissue samples of 39 rats analyzed tested negative for SARS-CoV-2 RNA. Conclusion: This is the first study that evaluates SARS-CoV-2 infection in urban rats. We can conclude that the sample of 39 rats had never been infected with SARS-CoV-2. We show that diagnostic serology tests can give misleading results when applied on non-human samples. SARS-CoV-2 monitoring activities should continue due to the emergence of new variants prone to infect Muridae rodents.
Subject(s)
COVID-19 , Rodent DiseasesABSTRACT
Background: The COVID-19 pandemic has imposed an enormous burden on health care systems around the world. In the past, the administration of convalescent plasma of patients having recovered from SARS and severe influenza to patients actively having the disease, showed promising effects on mortality and appeared safe. Whether or not this also holds true for the novel SARS-CoV-2 virus is currently unknown. Methods: DAWn-Plasma is a multicentre nation-wide, randomized, open-label, phase II proof-of-concept clinical trial, evaluating the clinical efficacy and safety of the addition of convalescent plasma to the standard of care in patients hospitalized with COVID-19 in Belgium. Patients hospitalized with a confirmed diagnosis of COVID-19 are eligible when they are symptomatic (i.e. clinical or radiological signs) and have been diagnosed with COVID-19 in the 72 hours before study inclusion through a PCR (nasal/nasopharyngeal swab or bronchoalveolar lavage) or a chest-CT scan showing features compatible with COVID-19 in the absence of an alternative diagnosis. Patients are randomized in a 2:1 ratio to either standard of care and convalescent plasma (active treatment group) or standard of care only. The active treatment group receives 2 units of 200 to 250 mL of convalescent plasma within 12 hours after randomization, with a second administration of 2 units 24 to 36 hours after ending the first administration. The trial aims to include 483 patients and will recruit from 25 centres across Belgium. The primary endpoint is the proportion of patients that require mechanical ventilation or have died at day 15. The main secondary endpoints are clinical status on day 15 and day 30 after randomization, as defined by the WHO Progression 10-point ordinal scale, and safety of the administration of convalescent plasma. Discussion: This trial will either provide support or discourage the use of convalescent plasma as early intervention for the treatment of hospitalized patients with COVID-19 infection. Trial registration: Clinicaltrials.gov, Identifier: NCT04429854. Registered 12 June 2020 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04429854.
Subject(s)
COVID-19ABSTRACT
Background: Given the current SARS-CoV-2 pandemic and the occurrence of a second wave, assessing the burden of disease among health care workers (HCWs) is crucial. We aim to document the prevalence of SARS-CoV-2 and the seroprevalence of anti-SARS-CoV-2 IgG among HCWs in Belgian hospitals, and to study potential risk factors for the infection in order to guide infection prevention and control (IPC) measures in healthcare institutions. Methods: We performed a cross-sectional analysis of the baseline results (April 22 - April 26) of an ongoing cohort study. All staff who were present in the hospital during the sampling period and whose profession involved contact with patients were eligible. Fourteen hospitals across Belgium and 50 HCW per hospital were randomly selected. RT-qPCR was performed to detect SARS-CoV-2 RNA on nasopharyngeal swabs, and a semi-quantitative IgG ELISA was used to detect anti-SARS-CoV-2 antibodies in sera. Individual characteristics likely to be associated with seropositivity were collected using an online questionnaire. Findings: 698 participants completed the questionnaire; 80.8% were women, median age was 39.5, and 58.5% were nurses. Samples were collected on all 699 participants. The weighted anti-SARS-CoV-2 IgG seroprevalence was 7.7% (95%CI, 4.7%-12.2%), while 1.1% (95%CI, 0.4%-3.0%) of PCR results were positive. Unprotected contact with a confirmed case was the only factor associated with seropositivity (PR 2.16, 95% CI, 1.4-3.2). Interpretation: Most Belgian HCW did not show evidence of SARS-CoV-2 infection by late April 2020, and unprotected contact was the most important risk factor. This confirms the importance of widespread availability of protective equipment and use of adequate IPC measures in hospital settings.