Risk of Dengue for Tourists and Teams during the World Cup 2014 in Brazil

Background

This year, Brazil will host about 600,000 foreign visitors during the 2014FIFA World Cup. The concern of possible dengue transmission during thisevent has been raised given the high transmission rates reported in the pastby this country.

Methodology/Principal Findings

We used dengue incidence rates reported by each host city during previousyears (2001–2013) to estimate the risk of dengue during the World Cupfor tourists and teams. Two statistical models were used: a percentile rank(PR) and an Empirical Bayes (EB) model. Expected IR''s during the games weregenerally low (<10/100,000) but predictions varied across locations andbetween models. Based on current ticket allocations, the mean number ofexpected symptomatic dengue cases ranged from 26 (PR,10^th–100^th percentile: 5–334 cases) to59 (EB, 95% credible interval: 30–77 cases) among foreigntourists but none are expected among teams. These numbers will highly dependon actual travel schedules and dengue immunity among visitors. Sensitivityanalysis for both models indicated that the expected number of cases couldbe as low as 4 or 5 with 100,000 visitors and as high as 38 or 70 with800,000 visitors (PR and EB, respectively).

Conclusion/Significance

The risk of dengue among tourists during the World Cup is expected to besmall due to immunity among the Brazil host population provided by lastyear''s epidemic with the same DENV serotypes. Quantitative risk estimates bydifferent groups and methodologies should be made routinely for massgathering events.