Earlier in February, I posted a chart showing the possible exponential growth of H7N9 cases in the People’s Republic of China (link). Exponential growth of infectious diseases among humans, however, can only occur if there is sustained human to human transmission. Although sporadic H7N9 cases have continued to be reported since early February, there has been no increase in number of family or local clusters that would signal sustained human to human transmission.
Importantly, the number of sporadic H7N9 cases has recently started to decline as depicted by the 2-week moving average in the chart below. Analysis of the data by reported onset dates indicates that the H7N9 infections started to decline about the middle of Week 6, about the same time that I posted the chart (link) with the projection of exponential growth of cases.