SARS-CoV-2 seroprevalence trends in healthy blood donors during the COVID-19 Milan outbreak
Open accessAbstract
Background&Aims: 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, the risk factors, and laboratory correlates. Methods: We conducted a cross-sectional study in a random sample of blood donors since the start of the outbreak (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, and for IgG+ was validated in a subset by an independent ELISA against the Spike protein (N=34, P<0.001). At the outbreak start, the overall adjusted seroprevalence of SARS-CoV-2 was 2.7%, 95% c.i. 0.3-6% (P<0.0001 vs. 120 historical controls). During the study period characterized by a gradual implementation of social distancing measures, there was a progressive increase in adjusted seroprevalence to 5.2%, 95% c.i. 2.4-9.0, due to a rise in IgG+ tests to 5%, 95%CI 2.8-8.2 (P=0.004 for trend, adjusted weekly increase 2.7+/-1.3%), but not of IgM+ (P=NS). At multivariate logistic regression analysis, seroconversion to IgG+ was more frequent in younger (P=0.043), while recent infections (IgM+) in older individuals (P=0.002). IgM+ was independently associated with higher triglycerides, eosinophils, and lymphocytes (P<0.05). Conclusions: SARS-CoV-2 infection was already circulating in Milan at the outbreak start. Social distancing may have been more effective in younger individuals, and by the end of April 2.4-9.0% of healthy adults had evidence of seroconversion. Asymptomatic infection may affect lipid profile and blood count.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Several countries have monitored seroprevalence in blood transfusion donors or expectant mothers attending antenatal clinics.
“Several countries have monitored seroprevalence in blood transfusion donors (12, 13) or expectant mothers attending antenatal clinics (14).”
From Seroprevalence of anti–SARS-CoV-2 IgG antibodies in Kenyan blood donors (2021) · cites this paper as [12]
Our results are also comparable with those of other surveys of blood donors in Brazil, Italy, and many parts of England.
“Our results are also comparable with those of other surveys of blood donors in Brazil (13), Italy (12), and many parts of England (19).”
From Seroprevalence of anti–SARS-CoV-2 IgG antibodies in Kenyan blood donors (2021) · cites this paper as [12]
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
No citation lists for this paper
No citation lists for this paper yet — checked again daily.
References 18 · Cited by 88
Research works printed but not linked: 1
- Prati D, Capelli C, Zanella A, Bosoni P, De Mattei C, Mozzi F, et al. Asymptomatic hepatitis G virus infection in blood donors. Transfusion. 1997;37(11-12):1200-4. doi: 10.1046/j.1537- 2995.1997.37111298088052.x · DOI
- Authors
- Valenti, L., Bergna, A., Pelusi, S., Facciotti, F., Lai, A., Tarkowski, M., Berzuini, A., Caprioli, F., Santoro, L., Baselli, G., Della Ventura, C., Erba, E., Bosari, S., Galli, M., Zehender, G., & Prati, D.
- Affiliations
- University of Milan (IT)
- European Institute of Oncology (IT)
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico (IT)
- Corresponding author
- Valenti, Luca
- Prati, Daniele
- ORCID
- Venue
- medRxiv
- Publisher
- openRxiv
- Published
- 2020-05-18
- OpenAlex
- W3024007010
- Cited by
- 88
- References
- 18
- Citations by year
- 2025: 1 · 2023: 4 · 2022: 9 · 2021: 31 · 2020: 43
- Type
- posted content
- Language
- en
- Open access
- green
- doi.org
- Licence
- cc-by-nc-nd
- Locations
- medRxiv (acceptedVersion, cc-by-nc-nd)
- Topics
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 and COVID-19 Research
- Health Sciences › Medicine › Infectious Diseases › SARS-CoV-2 detection and testing
- Physical Sciences › Mathematics › Modeling and Simulation › COVID-19 epidemiological studies
- Keywords
- SARS-CoV-2, COVID-19 pandemic, seroprevalence, blood donors, asymptomatic infection, seroconversion, IgM and IgG antibodies, nucleocapsid protein, spike protein, social distancing, risk factors, lipid profile, eosinophils, lymphocytes
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
