TY - JOUR
T1 - Early detection of variants of concern via funnel plots of regional reproduction numbers
AU - Milanesi, Simone
AU - Rosset, Francesca
AU - Colaneri, Marta
AU - Giordano, Giulia
AU - Pesenti, Kenneth
AU - Blanchini, Franco
AU - Bolzern, Paolo
AU - Colaneri, Patrizio
AU - Sacchi, Paolo
AU - De Nicolao, Giuseppe
AU - Bruno, Raffaele
PY - 2023
Y1 - 2023
N2 - Early detection of the emergence of a new variant of concern (VoC) is essential to develop strategies that contain epidemic outbreaks. For example, knowing in which region a VoC starts spreading enables prompt actions to circumscribe the geographical area where the new variant can spread, by containing it locally. This paper presents ‘funnel plots’ as a statistical process control method that, unlike tools whose purpose is to identify rises of the reproduction number (Rt), detects when a regional Rt departs from the national average and thus represents an anomaly. The name of the method refers to the funnel-like shape of the scatter plot that the data take on. Control limits with prescribed false alarm rate are derived from the observation that regional Rt's are normally distributed with variance inversely proportional to the number of infectious cases. The method is validated on public COVID-19 data demonstrating its efficacy in the early detection of SARS-CoV-2 variants in India, South Africa, England, and Italy, as well as of a malfunctioning episode of the diagnostic infrastructure in England, during which the Immensa lab in Wolverhampton gave 43,000 incorrect negative tests relative to South West and West Midlands territories.
AB - Early detection of the emergence of a new variant of concern (VoC) is essential to develop strategies that contain epidemic outbreaks. For example, knowing in which region a VoC starts spreading enables prompt actions to circumscribe the geographical area where the new variant can spread, by containing it locally. This paper presents ‘funnel plots’ as a statistical process control method that, unlike tools whose purpose is to identify rises of the reproduction number (Rt), detects when a regional Rt departs from the national average and thus represents an anomaly. The name of the method refers to the funnel-like shape of the scatter plot that the data take on. Control limits with prescribed false alarm rate are derived from the observation that regional Rt's are normally distributed with variance inversely proportional to the number of infectious cases. The method is validated on public COVID-19 data demonstrating its efficacy in the early detection of SARS-CoV-2 variants in India, South Africa, England, and Italy, as well as of a malfunctioning episode of the diagnostic infrastructure in England, during which the Immensa lab in Wolverhampton gave 43,000 incorrect negative tests relative to South West and West Midlands territories.
UR - http://www.scopus.com/inward/record.url?scp=85146600293&partnerID=8YFLogxK
U2 - 10.1038/s41598-022-27116-8
DO - 10.1038/s41598-022-27116-8
M3 - Article
C2 - 36658143
AN - SCOPUS:85146600293
SN - 2045-2322
VL - 13
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 1052
ER -