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Background Serology testing is explored for epidemiological research and to inform individuals after suspected infection. During the coronavirus disease 2019 (COVID-19) pandemic, frontline healthcare professionals (HCP) may be at particular risk for infection. No longitudinal data on functional seroconversion in HCP in regions with low COVID-19 prevalence and low pre-test probability exist. Methods In a large German university hospital, we performed weekly questionnaire assessments and anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) measurements with various commercial tests, a novel surrogate virus neutralisation test, and a neutralisation assay using live SARS-CoV-2. Results From baseline to week 6, 1080 screening measurements for anti-SARS CoV-2 (S1) IgG from 217 frontline HCP (65% female) were performed. Overall, 75.6% of HCP reported at least one symptom of respiratory infection. Self-perceived infection probability declined over time (from mean 20.1% at baseline to 12.4% in week 6, p

Purpose The coronavirus disease 19 (COVID-19) pandemic affects students in a myriad of different ways. Our prospective, longitudinal study in a cohort of students in Hannover, Germany explores behavioral patterns during escalating COVID-19 restrictions. Methods 777 students between the age of 9 and 20 were assessed for their activity engagement, travel patterns and self-assessed compliance with protective recommendations at six time points between June 2020 and June 2021 (3564 observations) and were monitored for SARS-CoV-2 infection by nasal swab PCR and serum antibody titers. Results Activity engagement decreased, but self-assessed compliance with measures such as mask wearing and social distancing was stable during escalating restrictions. While we found no sex difference during the summer break, when incidence was lowest, females engaged in a higher variety of activities than males for all other time points. Older students engaged in more activities and self-assigned themselves lower compliance values than younger ones. Greater involvement in different activities was seen in households which traveled more frequently. Infection rate in our cohort was low (0.03% acute infections, 1.94% positive sero-prevalence). Conclusion Our study supports the view that, overall, students show high compliance with COVID-19 recommendations and restrictions. The identification of subsets, such as female and older students, with higher-risk behavioral patterns should be considered when implementing public information campaigns. In light of the low infection rate in our cohort, we conclude that in-person learning can occur safely if extensive protective measures are in place and the incidence in the general population remains moderate., Graphical abstract

Background Vaccine-induced neutralizing antibodies are key in combating the coronavirus disease 2019 (COVID-19) pandemic. However, delays of boost immunization due to limited availability of vaccines may leave individuals vulnerable to infection and prolonged or severe disease courses. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOC)—B.1.1.7 (United Kingdom), B.1.351 (South Africa), and P.1 (Brazil)—may exacerbate this issue, as the latter two are able to evade control by antibodies. Methods We assessed humoral and T-cell responses against SARS-CoV-2 wild-type (WT), VOC, and endemic human coronaviruses (hCoVs) that were induced after single and double vaccination with BNT162b2. Results Despite readily detectable immunoglobulin G (IgG) against the receptor-binding domain of the SARS-CoV-2 S protein at day 14 after a single vaccination, inhibition of SARS-CoV-2 S-driven host cell entry was weak and particularly low for the B.1.351 variant. Frequencies of SARS-CoV-2 WT and VOC-specific T cells were low in many vaccinees after application of a single dose and influenced by immunity against endemic hCoV. The second vaccination significantly boosted T-cell frequencies reactive for WT and B.1.1.7 and B.1.351 variants. Conclusions These results call into question whether neutralizing antibodies significantly contribute to protection against COVID-19 upon single vaccination and suggest that cellular immunity is central for the early defenses against COVID-19., We assessed single vaccine shot–induced B- and T-cell responses against SARS-CoV-2, variants of concern, and human coronaviruses to determine protection against COVID-19. Our results provide important information about surrogates of protection, test result interpretation, and clinical decision-making.

Vaccine-induced neutralizing antibodies are key in combating the COVID-19 pandemic. However, delays of boost immunization due to limited availability of vaccines may leave individuals vulnerable to infection and disease for prolonged periods. The emergence of SARS-CoV-2 variants of concern (VOC), B.1.1.7 (United Kingdom), B.1.351 (South Africa) and P.1 (Brazil), may reinforce this issue with the latter two being able to evade control by antibodies. We assessed humoral and T cell responses against SARS-CoV-2 WT and VOC and endemic human coronaviruses (hCoV) that were induced after single and double vaccination with BNT162b2. Despite readily detectable IgG against the receptor-binding domain (RBD) of the SARS-CoV-2 S protein at day 14 after a single vaccination, inhibition of SARS-CoV-2 S-driven host cell entry was weak and particularly low for the B.1.351 variant. Frequencies of SARS-CoV-2 specific T cells were low in many vaccinees after application of a single dose and influenced by immunity against endemic hCoV. The second vaccination significantly boosted T cell frequencies reactive for WT, B.1.1.7 and B.1.351 variants. These results call into question whether neutralizing antibodies significantly contribute to protection against COVID-19 upon single vaccination and suggest that cellular immunity is central for the early defenses against COVID-19.

BackgroundSerology testing is explored for epidemiological research and to inform individuals after suspected infection. During the COVID-19 pandemic, frontline healthcare professionals (HCP) may be at particular risk for infection. No longitudinal data on functional seroconversion in HCP in regions with low COVID-19 prevalence and low pre-test probability exist.MethodsIn a large German university hospital, we performed weekly questionnaire assessments and anti-SARS-CoV-2 IgG measurements with various commercial tests, a novel surrogate virus neutralization test, and a neutralization assay using live SARS-CoV-2.ResultsFrom baseline to week six, n=1,080 screening measurements for anti-SARS CoV-2 (S1) IgG from n=217 frontline HCP (65% female) were performed. Overall, 75.6% of HCP reported at least one symptom of respiratory infection. Self-perceived infection probability declined over time (from mean 20.1% at baseline to 12·4 % in week six, pConclusionWhen assessing anti-SARS-CoV-2 immune status in individuals with low pre-test probability, we suggest confirming positive results from single measurements by alternative serology tests or functional assays. Our data highlight the need for a methodical serology screening approach in regions with low SARS-CoV-2 infection rates.

Background The COVID-19 pandemic has disrupted healthcare systems worldwide. In addition to the direct impact of the virus on patient morbidity and mortality, the effect of lockdown strategies on health and healthcare utilization have become apparent. Little is known on the effect of the pandemic on pediatric and adolescent medicine. We examined the impact of the pandemic on pediatric emergency healthcare utilization. Methods We conducted a monocentric, retrospective analysis of n = 5,424 pediatric emergency department visits between January 1st and April 19th of 2019 and 2020, and compared healthcare utilization during the pandemic in 2020 to the same period in 2019. Results In the four weeks after lockdown in Germany began, we observed a massive drop of 63.8% in pediatric emergency healthcare utilization (mean daily visits 26.8 ± SEM 1.5 in 2019 vs. 9.7 ± SEM 1 in 2020, p p p Conclusions Our data illustrate a significant decrease in pediatric emergency department visits during the COVID-19 pandemic. Public outreach is needed to encourage parents and guardians to seek medical attention for pediatric emergencies in spite of the pandemic.