BACKGROUND: The Milan metropolitan area in Northern Italy was among the most severely hit by the SARS-CoV-2 outbreak. The aim of this study was to examine the seroprevalence trends of SARS-CoV-2 in healthy asymptomatic adults, and the risk factors and laboratory correlates of positive tests. MATERIALS AND METHODS: We conducted a cross-sectional study in a random sample of blood donors, who were asymptomatic at the time of evaluation, at the beginning of the first phase (February 24th to April 8th 2020; n=789). Presence of IgM/IgG antibodies against the SARS-CoV-2-Nucleocapsid protein was assessed by a lateral flow immunoassay. RESULTS: The test had a 100/98.3 sensitivity/specificity (n=32/120 positive/negative controls, respectively), and the IgG test was validated in a subset by an independent ELISA against the Spike protein (n=34, p<0.001). At the start of the outbreak, the overall adjusted seroprevalence of SARS-CoV-2 was 2.7% (95% CI: 0.3-6%; p<0.0001 vs 120 historical controls). During the study period, characterised by a gradual implementation of social distancing measures, there was a progressive increase in the adjusted seroprevalence to 5.2% (95% CI: 2.4-9.0; 4.5%, 95% CI: 0.9-9.2% according to a Bayesian estimate) due to a rise in IgG reactivity to 5% (95% CI: 2.8-8.2; p=0.004 for trend), but there was no increase in IgM+ (p=not significant). At multivariate logistic regression analysis, IgG reactivity was more frequent in younger individuals (p=0.043), while IgM reactivity was more frequent in individuals aged >45 years (p=0.002). DISCUSSION: SARS-CoV-2 infection was already circulating in Milan at the start of the outbreak. The pattern of IgM/IgG reactivity was influenced by age: IgM was more frequently detected in participants aged >45 years. By the end of April, 2.4-9.0% of healthy adults had evidence of seroconversion.
BACKGROUND: The Milan metropolitan area in Northern Italy was among the most severely hit by the SARS-CoV-2 outbreak. The aim of this study was to examine the seroprevalence trends of SARS-CoV-2 in healthy asymptomatic adults, and the risk factors and laboratory correlates of positive tests. MATERIALS AND METHODS: We conducted a cross-sectional study in a random sample of blood donors, who were asymptomatic at the time of evaluation, at the beginning of the first phase (February 24th to April 8th 2020; n=789). Presence of IgM/IgG antibodies against the SARS-CoV-2-Nucleocapsid protein was assessed by a lateral flow immunoassay. RESULTS: The test had a 100/98.3 sensitivity/specificity (n=32/120 positive/negative controls, respectively), and the IgG test was validated in a subset by an independent ELISA against the Spike protein (n=34, p<0.001). At the start of the outbreak, the overall adjusted seroprevalence of SARS-CoV-2 was 2.7% (95% CI: 0.3-6%; p<0.0001 vs 120 historical controls). During the study period, characterised by a gradual implementation of social distancing measures, there was a progressive increase in the adjusted seroprevalence to 5.2% (95% CI: 2.4-9.0; 4.5%, 95% CI: 0.9-9.2% according to a Bayesian estimate) due to a rise in IgG reactivity to 5% (95% CI: 2.8-8.2; p=0.004 for trend), but there was no increase in IgM+ (p=not significant). At multivariate logistic regression analysis, IgG reactivity was more frequent in younger individuals (p=0.043), while IgM reactivity was more frequent in individuals aged >45 years (p=0.002). DISCUSSION: SARS-CoV-2 infection was already circulating in Milan at the start of the outbreak. The pattern of IgM/IgG reactivity was influenced by age: IgM was more frequently detected in participants aged >45 years. By the end of April, 2.4-9.0% of healthy adults had evidence of seroconversion.
Authors: Muhammad Nisar Khan; Haleema Khan; Muhammad Shahzad; Muhammad Ibrahim; Muhammad Arif; Zeeshan Kibria; Usman Waheed; Noore Saba; Inayat Shah; Yasar Mehmood Yousafzai Journal: Am J Blood Res Date: 2022-06-20
Authors: Cécile Tran Kiem; Pascal Crépey; Paolo Bosetti; Daniel Levy Bruhl; Yazdan Yazdanpanah; Henrik Salje; Pierre-Yves Boëlle; Simon Cauchemez Journal: Euro Surveill Date: 2021-06
Authors: Marina Pollán; Beatriz Pérez-Gómez; Roberto Pastor-Barriuso; Jesús Oteo; Miguel A Hernán; Mayte Pérez-Olmeda; Jose L Sanmartín; Aurora Fernández-García; Israel Cruz; Nerea Fernández de Larrea; Marta Molina; Francisco Rodríguez-Cabrera; Mariano Martín; Paloma Merino-Amador; Jose León Paniagua; Juan F Muñoz-Montalvo; Faustino Blanco; Raquel Yotti Journal: Lancet Date: 2020-07-06 Impact factor: 79.321
Authors: Karl Njuwa Fai; Tchoula Mamiafo Corine; Lisa M Bebell; Akenji Blaise Mbroingong; E B P Taa Nguimbis; Robert Nsaibirni; Nicoule Fouda Mbarga; Lucrece Eteki; Birgit Nikolay; Rene Ghislain Essomba; Mark Ndifon; Rodrigue Ntone; Achta Hamadou; Lucrece Matchim; Dora Tchiasso; Aristide Abbah; Rachel Essaka; Solange Peppa; Fouda Crescence; Jean Patrick Ouamba; Modeste Tamakloé Koku; Nadia Mandeng; Mahamat Fanne; Sarah Eyangoh; Georges Alain Etoundi Mballa; Linda Esso; Emilienne Epée; Richard Njouom; Marie Claire Okomo; Yap Boum Journal: Sci Afr Date: 2021-05-30
Authors: Amedeo De Nicolò; Valeria Avataneo; Jessica Cusato; Alice Palermiti; Jacopo Mula; Elisa De Vivo; Miriam Antonucci; Stefano Bonora; Andrea Calcagno; Giovanni Di Perri; Francesco Giuseppe De Rosa; Antonio D'Avolio Journal: Diagnostics (Basel) Date: 2021-05-12