Early Estimation of the Reproduction Number in the Presence of Imported Cases: Pandemic Influenza H1N1-2009 in New Zealand
2011

Estimating the Reproduction Number of H1N1-2009 in New Zealand

publication 10 minutes Evidence: moderate

Author Information

Author(s): Michael George Roberts, Hiroshi Nishiura

Primary Institution: Massey University, Auckland, New Zealand

Hypothesis

How can we accurately estimate the reproduction number of H1N1-2009 in the presence of imported cases?

Conclusion

The study found that the reproduction number for H1N1-2009 in New Zealand was estimated to be 1.25, accounting for imported cases and infection-age distribution.

Supporting Evidence

  • The study highlights the importance of accounting for imported cases in estimating the reproduction number.
  • It demonstrates that the infection-age distribution can significantly affect the estimation of transmission potential.
  • The findings suggest that previous estimates of the reproduction number may have been overestimated due to not considering these factors.

Takeaway

This study helps us understand how many people one sick person might infect during the H1N1 outbreak in New Zealand, showing that we need to consider travelers when figuring this out.

Methodology

The study used a renewal process model to estimate the reproduction number while accounting for imported cases and the infection-age distribution.

Potential Biases

Potential biases include misclassification of cases and the assumption of homogeneous mixing without accounting for age-related heterogeneity.

Limitations

The estimate is based on daily incidences of confirmed cases, which may have classification issues, and the generation time distribution was based on published results rather than direct estimation.

Participant Demographics

The mean and median ages of local confirmed cases were 22.4 and 19.0 years, respectively, with 51.4% of cases being children.

Statistical Information

P-Value

1.25

Confidence Interval

95% CI: 1.07, 1.47

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0017835

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