HK UNIVERSITY scientists talk about the revelations of the 2016-2017 Hong Kong flu: the pros and cons of information disclosure

original article was posted on The Emerging Microbes and Apps on September 6, 2017 under the headline To announce or not to announce: What is known about the 2016-2017 influenza season in Hong Kong?
Zhang Baixuan Chen Zhiping Jin Dongxuan
The Faculty of Biomedical Sciences of the University of Hong Kong
The death toll from seasonal influenza in Hong Kong in 2017 has flooded the domestic and foreign media, and some have compared it to the death toll from the SARS outbreak in 2003. How serious is the situation?
as of August 26, 2017, seasonal influenza activity in Hong Kong continued to decline and reach baseline levels in 2016-2017, indicating that the current quarter has officially ended. From 5 May to 26 August, a total of 586 serious cases included 19 children under the age of 18, of whom 431, including 3 children, died. A large number of influenza patients need to be hospitalized, with the majority over the age of 65. H3N2 is the main virus subsype of the epidemic.
known H3N2 subsypes to be more toxic than other subsypes such as H1N1, resulting in a higher number of serious illnesses and deaths. It remains to be seen whether the dominant H3N2 virus in the current quarter reduced vaccine effectiveness due to antigen drift, as was the case in 2014-2015. It is worth noting that more than 30% of the H3N2 strains isolated in Hong Kong in May 2017 have N121K mutations in their hemocoagulant genes, which may indeed affect the protection of the vaccine. But how much of an impact such antigen drift will have on the Hong Kong flu this season will require more research to determine. Since more than 40% of deaths have been given this year's flu vaccine, the effectiveness of the vaccine is in doubt.
this season's flu more severe than ever before? The most recent year for which H3N2 was the main popular subtype was 2014-2015, while the main popular subtype for 2013-2014 and 2015-2016 was H1N1. Seasonal flu has peaked in February and March for the past three years, with another extra small peak in June 2015, but this year's peak occurred in July. Due to the high toxicity of H3N2, there were more serious cases and deaths in 2014-2015 than in the previous two years. But the number of serious illnesses and deaths in 2016-2017 exceeded that in 2014-2015. The case mortality rate in both years was about 2 per cent.
comparison shows that seasonal influenza in Hong Kong in 2016-2017 was not more severe than in previous years when H3N2 was the main pandemic subtype. If broken down by age group, the situation was similar in 2014-2015 and 2016-2017, with complications and immunodeficiance common in both age groups aged 50-64 and over. A similar situation was not seen at all in 2013-2014 and 2015-2016. A more in-depth comparison shows that the higher hospitalization, sepsis and fatality rates experienced during the quarter did not exceed previous years in which H3N2 was the leading prevalence subsype around the world.
the medical burden of seasonal influenza has not been significant for a long time. The CDC estimates that between 9 million and 36 million flu-related cases have been reported in the United States each year since 2010, with 140,000 to 710,000 hospitalizations and 12,000 to 56,000 deaths. In 2003-2004, when H3N2 was the main pandemic subtype, nearly 50,000 people were estimated to have died from influenza-related respiratory and circulatory diseases in the United States. In other words, the advanced influenza surveillance system adopted in Hong Kong only provides true evidence of the CDC's projections.
Centre for Health Protection has successfully monitored the activity of seasonal influenza in Hong Kong in near real time. Starting in 2014-2015, the center has further made information public, reporting the number of severe cases and deaths of seasonal influenza to the public on a weekly basis. On the one hand, this approach can enhance public awareness and alertness to seasonal influenza, and on the other hand, it will lead to extensive media coverage, including exaggerated and improper comparisons, which will cause unnecessary panic, anxiety and overreaction among the public, visitors and neighbouring areas.
deaths from influenza-related complications are often difficult to track and are difficult to detect in a timely manner in nearby influenza surveillance systems. Therefore, direct comparison may not be able to truly reflect the actual activity of seasonal influenza between different regions. Human mortality rates from H5N1 and H7N9 avian influenza were 60% and 40%, respectively, and SARS and MERS mortality rates were 10% and 30%, respectively. These new viral diseases are highly unusual. If seasonal flu is a known ghost, they are unknown demons, and the two cannot be equal.
the right direction to improve the transparency of influenza surveillance and provide the public with more information about seasonal influenza, going back and not publishing information is not the way out. The question is how to educate the public and other holders at the same time as the information is made public so that they can better understand seasonal influenza and other new infectious diseases and pathogenic microorganisms . There is still a lot of room to do better in this regard.
the number of serious cases and deaths of seasonal influenza in Hong Kong in 2016-2017 reminds us that the health damage and deaths caused by seasonal influenza deserve attention. There is a long way to go to reduce the damage caused by seasonal influenza, especially to Hong Kong's public hospitals. The proportion of high-risk groups in Hong Kong, such as children, the elderly and health professionals, is relatively low. Providing more incentives to vaccinate them, such as appropriate financial subsidies, is worth exploring and piloting. The disciplinary action against the high-risk elderly as a special effect of influenza, Teminfo, has been shown to be a safe and effective preventive measure. Early fears that the use of Tyminfo would speed up the emergence of drug resistance were likely to be over-the-counter. In short, seasonal influenza remains an important research topic, while new vaccines and antiviral drugs are new hope for the fight against influenza.。