Sequential episodes of dengue--Puerto Rico, 2005-2010

Abstract

Of 53,633 suspected dengue cases reported to a passive dengue surveillance system in Puerto Rico during 2005-2010, 949 individuals were reported on more than one occasion and 21 had laboratory-confirmed dengue on two separate occasions. Median time between illness episodes was 2.9 years (range: 62 days-5.3 years). Seventeen (81%) individuals with sequential episodes of dengue were male, and seven (33%) were adults. All 21 individuals experienced one episode and seven (33%) individuals experienced both episodes during a large epidemic that occurred in 2010. These observations show that heterotypic dengue virus immunity that protects against illness may have considerable variability but typically does not last longer than 3 years.

Figure 1.

Time between illness onset dates for individuals experiencing sequential episodes of dengue in Puerto Rico, 2005–2010 (N = 21). Plotted on the y axis is the number of reported, laboratory-positive dengue cases each week between 2005 and 2010. Each horizontal black line represents one individual that experienced sequential episodes of dengue. The start point of each line indicates the onset date of the first reported illness, and the end point indicates the onset date of the second reported illness. Lines are ordered vertically by length.