More H7N9 cases can be expected in the next several weeks

Based on the reports from the People’s Republic of China (China), there is only limited human to human transmission of the novel A(H7N9) influenza virus.  However the number of sporadic cases reported by China is increasing dramatically.  The distribution of reported cases since November of 2013  has been increasing almost geometrically (graph below). Based on the trendline, between 30-40 cases per week may be expected within the next several weeks in China.

Graph notes: The weekly totals are counts based on reported onset dates for the 2013-2014 influenza season. The data do not include 18 cases announced in the past several days for which onset dates have not yet been reported.

Map: H7N9 cases concentrated in northern Zhejiang Province, PRC

Since novel A(H7N9) human infections were first discovered last year in the People's Republic of China, Zhejiang Province has reported the most cases. The map below depicts in aggregate, the general locations of 80 confirmed and unconfirmed cases through January 21, 2014. The cases are concentrated in the northern portion of the country in the Hangzhou and Huzhou. About 70% of all H7N9 cases reported from Zhejiang are from these two prefectures. 

Doctor dies from H7N9 in Shanghai

Chinese translations of media reports by FluTracker’s members indicated that an emergency room doctor has died from an H7N9 infection.(link) If this is confirmed by the World Health Organization it would only be the second confirmed health care worker (HCW) infected with H7N9. The last HCW infected by H7N9 was reported in April 2013.(link) Public health officials are always concerned about reports of health care workersinfected by novel infectious diseases because it is generally a sign of human-to-human transmission.

CSI 300 Index (China) Trending Down as Number of H7N9 Cases Increases

The chart below is an update to the chart presented on January 14 in Comparison of the CSI 300 Index (China) with the Recent Increase in H7N9 Cases. 

The graph below presents the H7N9 case counts based only on the date of report rather than a combination of onset dates and report dates. This graph more accurately reflects the relationship between the increasing number of reported H7N9 cases and the declining CSI 300 index.

Graph: Comparison of the CSI 300 Index (China) with the recent increase in H7N9 Cases as of January 18, 2014

Map: Geolocations of Human A(H7N9) Cases in Eastern China and Taiwan as of January 17, 2014

The map shows the frequency range of human H7N9 cases by second level administrative divisions (generally prefecture-level cities) in the People’s Republic of China and Taiwan through January 17, 2014. The map is based on geolocational information for more than 190 confirmed and probable cases. Geolocational information for individual cases is derived from numerous online reports and believe to be relatively accurate.

Comparison of the CSI 300 Index (China) with the Recent Increase in H7N9 Cases

A variety of different approaches have been proposed over the years to assess potential outbreaks of circulating and novel infectious diseases. Besides traditional epidemiological measures, Google Flu Trends is the best known. Changes in economic indicators have sometimes been proposed as both leading and trailing indicators of infectious disease outbreaks; see this thread at FluTrackers Pandemic threat-level market indicators.

The China Securities Index 300 (CSI 300), also referred to as the Shanghai Shenzhen 300 Index, is a capitalization-weighted stock index designed to replication the performance of 300 major stocks on the Shanghai and Shenzhen stock exchanges. This index of China stocks has been down over the last 30 days as the number of H7N9 cases have been increasing. Whether the inverse correlation is a leading indicator of additional outbreaks of H7N9 or just a fortuitous coincidence will become apparent in the next several weeks.


 Graph: Comparison of the CSI 300 Index (China) with the recent increase in H7N9 Cases  

Map: General Geolocations of Human A(H7N9) in the People’s Republic of China

Map: Approximate Geolocation of A(H7N9) cases in Eastern China  by Flu Season (through January 12, 2014)

Map notes: Human infections of Influenza A(H7N9) were not identified until about half way through the 2012-2013 flu season. The start of the 2013-2014 flu season begins on September 29, 2013 for week number 40 (following the Center for Disease Control [USA] week numbering system). Some probable and cases as yet unconfirmed by the World Health Organization are included on this map. This map is current through January 12, 2014. Because the 2013-2014  flu season will continue for several more months additional A(H7N9) cases are expected.