The transmissibility estimation of influenza with early stage data of small-scale outbreaks in Changsha, China, 2005-2013.
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.
Department of Malaria,National Institute of Parasitic Diseases,Chinese Center for Disease Control and Prevention,Shanghai,People's Republic of China.
T M
TM
Chen
Hospital,Shanghai Normal University,Shanghai,People's Republic of China.
Q P
QP
Chen
Changsha Center for Disease Control and Prevention,Changsha,Hunan,People's Republic of China.
R C
RC
Liu
Mass Medical International,Brookline,MA,USA.
A
A
Szot
Changsha Center for Disease Control and Prevention,Changsha,Hunan,People's Republic of China.
S L
SL
Chen
Changsha Center for Disease Control and Prevention,Changsha,Hunan,People's Republic of China.
J
J
Zhao
Department of Malaria,National Institute of Parasitic Diseases,Chinese Center for Disease Control and Prevention,Shanghai,People's Republic of China.
S S
SS
Zhou
D000293:Adolescent; D000328:Adult; D000368:Aged; D050936:Basic Reproduction Number; D002648:Child; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D018562:Disease Transmission, Infectious; D005260:Female; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology* / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D055815:Young Adult
Influenza; mathematical model; reproduction number; small-scale outbreak