COVID-19: an outbreak in a nursing home in spring 2021: COVID 19 and Residential Homes

COVID-19: an outbreak in a nursing home in spring 2021

COVID 19 and Residential Homes


  • Silvana Castaldi Università degli Studi di Milano
  • Stefano Zani Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Italy
  • Alessia Lai Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Italy
  • Gianguglielmo Zehender Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Italy
  • Annalisa Bergna Department of Biomedical and Clinical Sciences L. Sacco, University of Milan, Italy
  • Catia Rossana Boriello ASST FBF e Sacco, Milan, Italy
  • Danilo Cereda UO Prevenzione Regione Lombardia, Italy


COVID 19; Residential Homes; Healthcare Workers; vaccination


Introduction: Nursing home residents were the most vulnerable population to be affected by Coronavirus disease 2019 (COVID-19) in Italy. The Italian vaccination strategy decided to indicate them as the target population in the first phase of the massive vaccination campaign. We carried out an analysis on an outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection which occurred in a nursing home in northern Italy (Cremona) after the administration of the complete vaccination cycle affecting most of the guests of the structure. Methods: Data relating to the outbreak were obtained through the Regional Surveillance System for Infectious Diseases of Lombardia Region. Results: During the outbreak, among the 61 guests, 56 were vaccinated. Thirty four were found positive for COVID-19: 22 were asymptomatic, 12 were symptomatic and 4 died. The observed difference in the number of deaths between vaccinated and non-vaccinated subjects was significant. During the outbreak 104 healthcare workers (HCWs) were employed in the nursing home, only 66 were vaccinated. Eight HCWs were found COVID-19 positive, 4 of them were vaccinated and of female gender. Conclusions: Similarly to data reported in literature for described outbreaks, we observed that the vaccine is able to protect from the symptomatic form and a valid antibody response protect from a symptomatic disease. The low number of HCWs found positive indicates a correct use of individual protective devices.

Author Biography

Silvana Castaldi, Università degli Studi di Milano

professore associato Dipartimento di Scienze Biomediche per la Salute



Comas-Herrera A, Zalakain J, Lemmon E, et al. Mortality associated with COVID-19 in care homes: international evidence. Article in, International Long-Term Care Policy Network, CPEC-LSE, 1st February 2021.

Bonanad C, García-Blas S, Tarazona-Santabalbina F, et al. The Effect of Age on Mortality in Patients With COVID-19: A Meta-Analysis With 611,583 Subjects. J Am Med Dir Assoc. 2020;21(7):915-918. doi:10.1016/j.jamda.2020.05.045

Gutiérrez Rodríguez J, Montero Muñoz J, Jiménez Muela F, Guirola García-Prendes C, Gómez AL. Variables associated with mortality in a selected sample of patients older than 80 years and with some degree of functional dependence hospitalized for COVID-19 in a geriatrics service. Rev Esp Geriatr Gerontol. 2020; 55: 317- 325.

Pagani G, Conti F, Giacomelli A, Bernacchiad et al. Seroprevalence of SARS-CoV-2 significantly varies with age: Preliminary results from a mass population screening. Journal of infection , 2020, Vol.81(6), p.e10-e12 DOI: 10.1016/j.jinf.2020.09.021

Hassan-Smith Z, Hanif W, Khunti K. Who should be prioritised for COVID-19 vaccines? Lancet. 2020 Nov 28;396(10264):1732-1733. doi: 10.1016/S0140-6736(20)32224-8. Epub 2020 Oct 27. PMID: 33125934; PMCID: PMC7832613.

Ministero della Salute, Circolare ministeriale 42164 “Raccomandazioni per l’organizzazione della campagna vaccinale contro SARS-CoV-2/COVID-19 e procedure di vaccinazione” del 24 dicembre 2020

Salmerón Ríos, S, Mas Romero, M, Cortés Zamora, EB, et al. Immunogenicity of the BNT162b2 vaccine in frail or disabled nursing home residents: COVID-A study. J Am Geriatr Soc. 2021; 69: 1441– 1447.

Regione Lombardia delibera regionale n° IX/3114 del 07/05/2020

Canaday DH, Carias L, Oyebanji OA, Keresztesy D, Wilk D, Payne M, Aung H, St Denis K, Lam EC, Wilson B, Rowley CF, Berry SD, Cameron CM, Cameron MJ, Balazs AB, Gravenstein S, King CL. Reduced BNT162b2 mRNA vaccine response in SARS-CoV-2-naive nursing home residents. medRxiv [Preprint]. 2021 Mar 22:2021.03.19.21253920. doi: 10.1101/2021.03.19.21253920. Update in: Clin Infect Dis. 2021 May 16;: PMID: 33791727; PMCID: PMC8010759.

Istituto Superiore di Sanità. Sesto Rapporto sull’ “impatto dell’epidemia COVID-19 sulla mortalità totale della popolazione residente”

Lombardi, Andrea; Consonni, Dario; Oggioni, Massimo; Bono, Patrizia; Renteria, et al. SARS-CoV-2 anti-spike antibody titres after vaccination with BNT162b2 in naïve and previously infected individuals. Journal of infection and public health. , 2021, Vol.14(8), p.1120-1122 DOI: 10.1016/j.jiph.2021.07.005

Consonni D. COVID-19: What happened to the healthcare workers of a research and teaching hospital in Milan, Italy? Acta bio-medica de L'Ateneo parmense 2020, Vol.91(3), p.1-5 DOI: 10.23750/abm.v91i3.10361

Istituto Superiore di Sanità.




How to Cite

Castaldi S, Zani S, Lai A, Zehender G, Bergna A, Boriello CR, et al. COVID-19: an outbreak in a nursing home in spring 2021: COVID 19 and Residential Homes. Acta Biomed [Internet]. 2021 Oct. 7 [cited 2024 Jul. 20];92(S6):e2021445. Available from: