1887
Research Open Access
Like 0

Abstract

Background

On 20 February 2020, a locally acquired coronavirus disease (COVID-19) case was detected in Lombardy, Italy. This was the first signal of ongoing transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the country. The number of cases in Italy increased rapidly and the country became the first in Europe to experience a SARS-CoV-2 outbreak.

Aim

Our aim was to describe the epidemiology and transmission dynamics of the first COVID-19 cases in Italy amid ongoing control measures.

Methods

We analysed all RT-PCR-confirmed COVID-19 cases reported to the national integrated surveillance system until 31 March 2020. We provide a descriptive epidemiological summary and estimate the basic and net reproductive numbers by region.

Results

Of the 98,716 cases of COVID-19 analysed, 9,512 were healthcare workers. Of the 10,943 reported COVID-19-associated deaths (crude case fatality ratio: 11.1%) 49.5% occurred in cases older than 80 years. Male sex and age were independent risk factors for COVID-19 death. Estimates of R varied between 2.50 (95% confidence interval (CI): 2.18–2.83) in Tuscany and 3.00 (95% CI: 2.68–3.33) in Lazio. The net reproduction number R in northern regions started decreasing immediately after the first detection.

Conclusion

The COVID-19 outbreak in Italy showed a clustering onset similar to the one in Wuhan, China. R at 2.96 in Lombardy combined with delayed detection explains the high case load and rapid geographical spread. Overall, R in Italian regions showed early signs of decrease, with large diversity in incidence, supporting the importance of combined non-pharmacological control measures.

Loading

Article metrics loading...

/content/10.2807/1560-7917.ES.2020.25.49.2000790
2020-12-10
2021-01-22
http://instance.metastore.ingenta.com/content/10.2807/1560-7917.ES.2020.25.49.2000790
Loading
Loading full text...

Full text loading...

/deliver/fulltext/eurosurveillance/25/49/eurosurv-25-49-4.html?itemId=/content/10.2807/1560-7917.ES.2020.25.49.2000790&mimeType=html&fmt=ahah

References

  1. Huang C, Wang Y, Li X, Ren L, Zhao J, Hu Y, et al. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020;395(10223):497-506.  https://doi.org/10.1016/S0140-6736(20)30183-5  PMID: 31986264 
  2. Chen N, Zhou M, Dong X, Qu J, Gong F, Han Y, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020;395(10223):507-13.  https://doi.org/10.1016/S0140-6736(20)30211-7  PMID: 32007143 
  3. Chan JF-W, Yuan S, Kok K-H, To KK-W, Chu H, Yang J, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020;395(10223):514-23.  https://doi.org/10.1016/S0140-6736(20)30154-9 
  4. Gorbalenya AE, Baker SC, Baric RS, de Groot RJ, Drosten C, Gulyaeva AA, et al. Severe acute respiratory syndrome-related coronavirus: The species and its viruses – a statement of the Coronavirus Study Group. bioRxiv. 2020 Jan 1;2020.02.07.937862.
  5. World Health Organization (WHO). Scientific Brief. Transmission of SARS-CoV-2: implications for infection prevention precautions. Geneva: WHO; 9 July 2020. Available from: https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions
  6. Bernard Stoecklin S, Rolland P, Silue Y, Mailles A, Campese C, Simondon A, et al. , Investigation Team. First cases of coronavirus disease 2019 (COVID-19) in France: surveillance, investigations and control measures, January 2020. Euro Surveill. 2020;25(6):2000094.  https://doi.org/10.2807/1560-7917.ES.2020.25.6.2000094  PMID: 32070465 
  7. Rothe C, Schunk M, Sothmann P, Bretzel G, Froeschl G, Wallrauch C, et al. Transmission of 2019-nCoV Infection from an Asymptomatic Contact in Germany. N Engl J Med. 2020;382(10):970-1.  https://doi.org/10.1056/NEJMc2001468 
  8. Moss P, Barlow G, Easom N, Lillie P, Samson A. Lessons for managing high-consequence infections from first COVID-19 cases in the UK. Lancet. 2020;395(10227):e46.  https://doi.org/10.1016/S0140-6736(20)30463-3  PMID: 32113507 
  9. Spiteri G, Fielding J, Diercke M, Campese C, Enouf V, Gaymard A, et al. First cases of coronavirus disease 2019 (COVID-19) in the WHO European Region, 24 January to 21 February 2020. Euro Surveill. 2020;25(9):2000178.  https://doi.org/10.2807/1560-7917.ES.2020.25.9.2000178  PMID: 32156327 
  10. Guzzetta G, Poletti P, Ajelli M, Trentini F, Marziano V, Cereda D, et al. Potential short-term outcome of an uncontrolled COVID-19 epidemic in Lombardy, Italy, February to March 2020. Euro Surveill. 2020;25(12):2000293.  https://doi.org/10.2807/1560-7917.ES.2020.25.12.2000293  PMID: 32234117 
  11. Cereda D, Tirani M, Rovida F, Demicheli V, Ajelli M, Poletti P, et al. The early phase of the COVID-19 outbreak in Lombardy, Italy. ArXiv200309320 Q-Bio. 2020 Mar 20. Available from: http://arxiv.org/abs/2003.09320
  12. Decree of the Prime Minister. Disposizioni attuative del decreto-legge 23 febbraio 2020, n. 6, recante misure urgenti in materia di contenimento e gestione dell’emergenza epidemiologica da COVID-19. (20A01228) (G.U. Serie Generale, n. 45 del 23 febbraio 2020). [Enactment of decree of 23 February no. 6 concerning urgent measures for the containment and management of the epidemiologic emergency caused by COVID-19]. Rome: Ministero della Salute; 23 Feb 2020. Italian. Available from: http://www.trovanorme.salute.gov.it/norme/dettaglioAtto?id=73196&articolo=6
  13. Decree of the Prime Minister. Ulteriori disposizioni attuative del decreto-legge 23 febbraio 2020, n. 6, recante misure urgenti in materia di contenimento e gestione dell’emergenza epidemiologica da COVID-19, applicabili sull’intero territorio nazionale. (20A01605) (G.U. Serie Generale, n. 64 del 11 marzo 2020). [Further enactment of decree of 23 February no. 6 concerning urgent measures for the containment and management of the epidemiologic emergency caused by COVID-19]. Rome: Ministero della Salute; 2020. Italian. Available from: http://www.trovanorme.salute.gov.it/norme/dettaglioAtto?id=73643
  14. European Centre for Disease Prevention and Control (ECDC). Case definition for coronavirus disease 2019 (COVID-19), as of 2 March 2020. Stockholm: ECDC; 2020. Available from: https://www.ecdc.europa.eu/en/case-definition-and-european-surveillance-human-infection-novel-coronavirus-2019-ncov
  15. Stefanelli P, Faggioni G, Lo Presti A, Fiore S, Marchi A, Benedetti E, et al. Whole genome and phylogenetic analysis of two SARS-CoV-2 strains isolated in Italy in January and February 2020: additional clues on multiple introductions and further circulation in Europe. Euro Surveill. 2020;25(13):2000305.  https://doi.org/10.2807/1560-7917.ES.2020.25.13.2000305  PMID: 32265007 
  16. Corman VM, Landt O, Kaiser M, Molenkamp R, Meijer A, Chu DK, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill. 2020;25(3):2000045.  https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045  PMID: 31992387 
  17. Centers for Disease Control and Prevention (CDC). Information for laboratories about coronavirus (COVID-19 . Atlanta: CDC; 2020. Available from: https://www.cdc.gov/coronavirus/2019-ncov/lab/rt-pcr-detection-instructions.html
  18. Italian Ministry of Health. Ministerial Decree N. 0007922 - COVID-19. Aggiornamento della definizione di caso. [Update on the case definition]. Rome: Ministry of Health; 2020. Italian. Available from: http://www.trovanorme.salute.gov.it/norme/renderNormsanPdf?anno=2020&codLeg=73669&parte=1%20&serie=null
  19. EpiCentro. Sorveglianza integrata COVID-19: i principali dati nazionali. [COVID-19 integrated surveillance: key national data]. Rome: Istituto Superiore di Sanità. [Accessed: 19 Mar 2020]. Italian. Available from: https://www.epicentro.iss.it/coronavirus/sars-cov-2-sorveglianza-dati
  20. WHO Ebola Response TeamAylward B, Barboza P, Bawo L, Bertherat E, Bilivogui P, et al. Ebola virus disease in West Africa--the first 9 months of the epidemic and forward projections. N Engl J Med. 2014;371(16):1481-95.  https://doi.org/10.1056/NEJMoa1411100  PMID: 25244186 
  21. Liu Q-H, Ajelli M, Aleta A, Merler S, Moreno Y, Vespignani A. Measurability of the epidemic reproduction number in data-driven contact networks. Proc Natl Acad Sci USA. 2018;115(50):12680-5.  https://doi.org/10.1073/pnas.1811115115  PMID: 30463945 
  22. Zhang J, Litvinova M, Liang Y, Wang Y, Wang W, Zhao S, et al. Changes in contact patterns shape the dynamics of the COVID-19 outbreak in China. Science. 2020;368(6498):1481-6.  https://doi.org/10.1126/science.abb8001 
  23. La Rosa G, Mancini P, Bonanno Ferraro G, Veneri C, Iaconelli M, Bonadonna L, et al. SARS-CoV-2 has been circulating in northern Italy since December 2019: Evidence from environmental monitoring. Sci Total Environ. 2020;750:141711.  https://doi.org/10.1016/j.scitotenv.2020.141711 
  24. Guzzetta G, Riccardo F, Marziano V, Poletti P, Trentini F, Bella A, et al. Impact of a Nationwide Lockdown on SARS-CoV-2 Transmissibility, Italy. Emerg Infect Dis. 2020;27(1).
  25. Barnett ML, Grabowski DC. Nursing homes are ground zero for COVID-19 pandemic. JAMA Health Forum. 2020 Mar 2;1(3):e200369–e200369.
  26. Acidoni A, Bacigalupo I, Bellomo M, Canevelli M, Carella MG, Confaloni A, et al. Survey nazionale sul contagio COVID-19 nelle strutture residenziali e sociosanitarie. Primo report. [National Survey on COVID-19 spread in nursing homes and long term care facilities. First report]. Rome: Instituto Superiore di Sanità; 30 March 2020. Italian. Available from: https://www.epicentro.iss.it/coronavirus/pdf/sars-cov-2-survey-rsa-rapporto.pdf
  27. Wu Z, McGoogan JM. Characteristics of and important lessons from the coronavirus disease 2019 (COVID-19) outbreak in China: Summary of a report of 72 314 cases from the Chinese Center for Disease Control and Prevention. JAMA. 2020;323(13):1239-42.  https://doi.org/10.1001/jama.2020.2648 
  28. Shah D. Healthy worker effect phenomenon. Indian J Occup Environ Med. 2009;13(2):77-9.  https://doi.org/10.4103/0019-5278.55123  PMID: 20386623 
  29. Statistiche demografiche ISTAT. [Italian official statistical demographics]. Rome: Istituto Nazionale di Statistica (ISTAT) [National Institute of Statistics]. [Accessed: 5 Apr 2020]. Italian. Available from: http://demo.istat.it/pop2019/index.html
  30. Onder G, Rezza G, Brusaferro S. Case-fatality rate and characteristics of patients dying in relation to COVID-19 in Italy. JAMA. 2020;323(18):1775-6.  https://doi.org/10.1001/jama.2020.4683 
  31. European Centre for Disease Prevention and Control. Rapid risk assessment: Coronavirus disease 2019 (COVID-19) pandemic: increased transmission in the EU/EEA and the UK – seventh update. Stockholm: ECDC; 2020. Available from: https://www.ecdc.europa.eu/en/publications-data/rapid-risk-assessment-coronavirus-disease-2019-covid-19-pandemic
  32. Italian Ministry of Health. Documento relativo ai criteri per sottoporre soggetti clinicamente asintomatici alla ricerca d’infezione da SARS-CoV-2attraverso tampone rino-faringeo e test diagnostico. [Criteria for SARS-CoV-2 diagnostic ascertainment of symptomatic people through nasopharyngeal swabbing and diagnostic test]. Rome: Ministry of Health; 22 Feb 2020. Italian. Available from: http://www.trovanorme.salute.gov.it/norme/renderNormsanPdf?anno=2020&codLeg=73444&parte=1%20&serie=null
  33. Michelozzi P, de’Donato F, Scortichini M, Pezzotti P, Stafoggia M, De Sario M, et al. Temporal dynamics in total excess mortality and COVID-19 deaths in Italian cities. BMC Public Health. 2020;20(1):1238.  https://doi.org/10.1186/s12889-020-09335-8 
  34. Scortichini M, Schneider dos Santos R, De’ Donato F, De Sario M, Michelozzi P, Davoli M, et al. Excess mortality during the COVID-19 outbreak in Italy: a two-stage interrupted time-series analysis. Int J Epidemiol. 2020;dyaa169.  https://doi.org/10.1093/ije/dyaa169 
  35. Blangiardo M, Cameletti M, Pirani M, Corsetti G, Battaglini M, Baio G. Estimating weekly excess mortality at sub-national level in Italy during the COVID-19 pandemic. PLoS One. 2020;15(10):e0240286.  https://doi.org/10.1371/journal.pone.0240286 
/content/10.2807/1560-7917.ES.2020.25.49.2000790
Loading

Data & Media loading...

Supplementary data

Submit comment
Close
Comment moderation successfully completed
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error