Effective high-throughput RT-qPCR screening for SARS-CoV-2 infections in children.

Systematic SARS-CoV-2 testing is a valuable tool for infection control and surveillance. However, broad application of high sensitive RT-qPCR testing in children is often hampered due to unpleasant sample collection, limited RT-qPCR capacities and high costs. Here, we developed a high-throughput approach ('Lolli-Method') for SARS-CoV-2 detection in children, combining non-invasive sample collection with an RT-qPCR-pool testing strategy. SARS-CoV-2 infections were diagnosed with sensitivities of 100% and 93.9% when viral loads were >106 copies/ml and >103 copies/ml in corresponding Naso-/Oropharyngeal-swabs, respectively. For effective application of the Lolli-Method in schools and daycare facilities, SEIR-modeling indicated a preferred frequency of two tests per week. The developed test strategy was implemented in 3,700 schools and 698 daycare facilities in Germany, screening over 800,000 individuals twice per week. In a period of 3 months, 6,364 pool-RT-qPCRs tested positive (0.64%), ranging from 0.05% to 2.61% per week. Notably, infections correlated with local SARS-CoV-2 incidences and with a school social deprivation index. Moreover, in comparison with the alpha variant, statistical modeling revealed a 36.8% increase for multiple (≥2 children) infections per class following infections with the delta variant. We conclude that the Lolli-Method is a powerful tool for SARS-CoV-2 surveillance and can support infection control in schools and daycare facilities.

Cumulative Incidence of SARS-CoV-2 in Healthcare Workers at a General Hospital in Germany during the Pandemic-A Longitudinal Analysis.

Health workers (HW) are at increased risk for SARS-CoV-2 infection. In order to monitor the infection dynamic on the basis of contact with patients, HW at the St. Antonius Hospital (SAH) were tested four times in one year by PCR and serology. The cumulative incidence of infection in HW was calculated. Swab and blood tests were simultaneously performed between April 2020 and April 2021. Risk factors and demographic information were assessed at the beginning of the study. The response rate was above 75% in all rounds of testing. The study comprised 1506 HW, 165 (10.6%) of which tested positive for SARS-CoV-2 infection. Working in an ICU or on wards with patient contact were risk factors (OR 4.4, 95% CI 1.73-13.6 and OR 2.9, 95% CI 1.27-8.49). At the end of the study, the majority of HW (810 of 1363 (59.4%)) had been vaccinated at least once. A total of 29.1% of unvaccinated HW and 5.3% of vaccinated HW showed an immune response typical for natural SARS-CoV-2 infection. Of the 73 HW who provided information on the course of the disease, 31.5% reported that their quality of life continued to be impaired. The cumulative incidence of infection was low in these HW, which may be attributed to vaccination and good hygiene. Nevertheless, a work-related infection risk was identified, highlighting the need to improve protection against infection. A high risk of developing long COVID was found after the infection has subsided. Special rehabilitation programs should be provided and HW should be compensated for reduced work capacity in the case that rehabilitation fails or takes a long time.

SARS-CoV-2 Infection in Fully Vaccinated Individuals of Old Age Strongly Boosts the Humoral Immune Response.

Prophylactic vaccination against SARS-CoV-2 is one of the most important measures to contain the COVID-19 pandemic. Recently, break-through infections following vaccination against this virus have been reported. Here, we describe the humoral immune response of break-through infections in fully vaccinated individuals of old age from an outbreak in a nursing home. In cooperation with the local health authority, blood samples from fully vaccinated and infected as well as fully vaccinated and uninfected residents of the nursing home were collected 4 weeks after the onset of the outbreak. The humoral immune response was determined in a neutralisation assay with replication-competent virus isolates and by a quantitative ELISA. In this outbreak a total of 23 residents and four health care workers were tested positive for SARS-CoV-2. Four residents were unvaccinated, including one with a severe course of disease who later severe disease course who later succumbed to infection. Despite their old age, all vaccinated residents showed no or only mild disease. Comparison of the humoral immune response revealed significantly higher antibody levels in fully vaccinated infected individuals compared to fully vaccinated uninfected individuals (p < 0.001). Notably, although only a minority of the vaccinated uninfected group showed neutralisation capacity against SARS-CoV-2, all vaccinated and infected individuals showed high-titre neutralisation of SARS-CoV-2 including the alpha and beta variant. Large SARS-CoV-2 outbreaks can occur in fully vaccinated populations, but seem to associate with mild disease. SARS-CoV-2 infection in fully vaccinated individuals is a strong booster of the humoral immune response providing enhanced neutralisation capacity against immune evasion variants.

SARS-CoV-2, CT-Values, and Infectivity-Conclusions to Be Drawn from Side Observations.

In their recent article published in Viruses, Michel Drancourt and colleagues [...].

[Prevalence of SARS-CoV-2 in employees of a general hospital in Northrhine-Westphalia, Germany]. / Prävalenz von SARS-CoV-2 bei Mitarbeitern eines Krankenhauses der Regel-/Schwerpunktversorgung in Nordrhein-Westfalen.

BACKGROUND: We assessed the prevalence of SARS-CoV-2 in the staff of a general hospital in North-Rhine-Westphalia in a cross-sectional study. METHOD: Employees (n = 1363) were offered a nasopharyngeal swab and serology for SARS-CoV-2. Additionally, employees completed a questionnaire about preexisting conditions, contacts with SARS-CoV-2-positive individuals and COVID-19-specific symptoms. RESULTS: 1212 employees participated. 19 of 1363 (1.4 %) employees tested positive by PCR (3 within and 16 before the study). 40 (3.3 %) and 105 (8.6 %) had IgG and IgA, respectively, 32 (2.6 %) both IgG and IgA. Overall, 47 employees tested positive. In this group, most frequently reported symptoms were headache (56 %), fatigue (49 %), sore throat (49 %), and cough (46 %); fever was reported by 33 %. SARS-CoV-2-positive employees reported more frequently contact with COVID-19 cases (60.5 % vs. 37.3 %, p = 0.006). Employees testing positive only for IgA reported less symptoms. CONCLUSION: Between 27.04. and 20.05.2020, 3.9 % of the employees working in a general hospital were tested positive for SARS-CoV-2. This proportion was lower than expected; possible explanations are the low level of endemic infection and the extensive, uniform in-house preventative measures.