The world is continuously vulnerable to the H1N1 influenza pandemic since 2009. The better understanding of the features of virus spread is crucial to enhancing the prevention and control of influenza. Using mathematical modelling, Dr He Daihai and his research team at the Department of Applied Mathematics conducted an in-depth study of the global spatio-temporal patterns of influenza dynamics.
Considered the virus diversity, the study examined the influenza transmission by analyzing and modelling weekly laboratory confirmed cases of influenza A and B from 138 countries in the post-pandemic period (2006-2015) with data obtained from the surveillance network compiled by the World Health Organization.
The study found a pattern of skip-and-resurgence behaviour between 2011 and 2013 for the influenza H1N1pdm, the strain responsible for the 2009 pandemic. In particular, the expected H1N1 epidemic outbreak in 2011 to 2012 failed to occur in Europe and Eastern Asia. In early 2011, it was also reported that a pattern of well-synchronized wave of H1N1pdm in the countries in the Northern Hemisphere, and a pattern of replacement of strain H1N1pre by H1N1pdm between the 2009 and 2012 influenza seasons. The understanding of these patterns has important public health implications.
In Hong Kong, the number of accumulated flu deaths from January-April 2015 is 451, which already exceeded the 299 SARS deaths from January 2002 to July 2003. In view of this, researchers also examined the vaccination policy in different countries and its impact on influenza transmission. They found that, the duration of immunity protection could be much shorter than expected. These findings can contribute to better disease control in Hong Kong.