The transmissibility estimation of influenza with early stage data of small-scale outbreaks in Changsha, China, 2005-2013

Epidemiol Infect. 2017 Feb;145(3):424-433. doi: 10.1017/S0950268816002508. Epub 2016 Nov 11.

Abstract

Hundreds of small-scale influenza outbreaks in schools are reported in mainland China every year, leading to a heavy disease burden which seriously impacts the operation of affected schools. Knowing the transmissibility of each outbreak in the early stage has become a major concern for public health policy-makers and primary healthcare providers. In this study, we collected all the small-scale outbreaks in Changsha (a large city in south central China with ~7·04 million population) from January 2005 to December 2013. Four simple and popularly used models were employed to calculate the reproduction number (R) of these outbreaks. Given that the duration of a generation interval Tc = 2·7 and the standard deviation (s.d.) σ = 1·1, the mean R estimated by an epidemic model, normal distribution and delta distribution were 2·51 (s.d. = 0·73), 4·11 (s.d. = 2·20) and 5·88 (s.d. = 5·00), respectively. When Tc = 2·9 and σ = 1·4, the mean R estimated by the three models were 2·62 (s.d. = 0·78), 4·72 (s.d. = 2·82) and 6·86 (s.d. = 6·34), respectively. The mean R estimated by gamma distribution was 4·32 (s.d. = 2·47). We found that the values of R in small-scale outbreaks in schools were higher than in large-scale outbreaks in a neighbourhood, city or province. Normal distribution, delta distribution, and gamma distribution models seem to more easily overestimate the R of influenza outbreaks compared to the epidemic model.

Keywords: Influenza; mathematical model; reproduction number; small-scale outbreak.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Basic Reproduction Number*
  • Child
  • China / epidemiology
  • Disease Outbreaks
  • Disease Transmission, Infectious*
  • Female
  • Humans
  • Influenza, Human / epidemiology*
  • Influenza, Human / transmission*
  • Male
  • Middle Aged
  • Models, Theoretical
  • Young Adult