Speed and strength of an epidemic intervention.
Proc Biol Sci
; 288(1947): 20201556, 2021 03 31.
Article
in English
| MEDLINE | ID: covidwho-1388073
ABSTRACT
An epidemic can be characterized by its strength (i.e., the reproductive number [Formula see text]) and speed (i.e., the exponential growth rate r). Disease modellers have historically placed much more emphasis on strength, in part because the effectiveness of an intervention strategy is typically evaluated on this scale. Here, we develop a mathematical framework for the classic, strength-based paradigm and show that there is a dual speed-based paradigm which can provide complementary insights. In particular, we note that r = 0 is a threshold for disease spread, just like [Formula see text] [ 1], and show that we can measure the strength and speed of an intervention on the same scale as the strength and speed of an epidemic, respectively. We argue that, while the strength-based paradigm provides the clearest insight into certain questions, the speed-based paradigm provides the clearest view in other cases. As an example, we show that evaluating the prospects of 'test-and-treat' interventions against the human immunodeficiency virus (HIV) can be done more clearly on the speed than strength scale, given uncertainty in the proportion of HIV spread that happens early in the course of infection. We also discuss evaluating the effects of the importance of pre-symptomatic transmission of the SARS-CoV-2 virus. We suggest that disease modellers should avoid over-emphasizing the reproductive number at the expense of the exponential growth rate, but instead look at these as complementary measures.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
HIV Infections
/
Epidemics
/
COVID-19
Type of study:
Experimental Studies
/
Observational study
/
Prognostic study
Topics:
Variants
Limits:
Humans
Language:
English
Journal:
Proc Biol Sci
Journal subject:
Biology
Year:
2021
Document Type:
Article
Affiliation country:
RSPB.2020.1556
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