Dengue Outbreak Undercounting Revealed

Throughout 2024, Dengue virus outbreaks have become significant public health problems. About half of the world's population is now at risk of Dengue.

Unfortunately, new data indicates Dengue's actual impact may be undercounted in areas with virus-type variabilities.

While inapparent infections are often overlooked and do not require immediate medical attention, researchers have assumed that they account for up to 88% of all Dengue transmission events.

Researchers recently wrote that estimates failing to represent the annual fluctuations in Dengue outbreaks highlight the need to improve disease burden forecasts and pre-outbreak vaccination programs.

Published on October 25, 2024, new research challenges previous assumptions of measuring Dengue outbreaks by demonstrating that inapparent and symptomatic primary Dengue virus (DENV) infections present distinct epidemiological profiles.

This study reveals that the epidemiological footprint of DENV's four virus types (1-4) is broader and more nuanced than previously recognized.

These researchers wrote, 'the majority of primary infections within our cohort were inapparent (76%), aligning with existing literature that suggests a high prevalence of inapparent and subclinical infection across dengue-endemic regions.

However, the proportion of inapparent infections greatly fluctuates across the years.

Characterizing these infections allowed us to examine the serotype-specific proportion of primary inapparent infections and their temporal variability for the first time.

Importantly, our study shows that while a single serotype often dominates symptomatic primary infections in any given period, the landscape of inapparent infections is far more complex.

It reveals the co-circulation of multiple serotypes and serotype circulation undetected in symptomatic cases across multiple years.

This observation suggests that the epidemiological footprint of DENV is broader and more nuanced than what is captured by monitoring symptomatic cases alone whenever there is a co-circulation of serotypes or hyperendemicity.

Our study, which dissected the entire disease spectrum associated with primary DENV infection, revealed stark serotype-specific differences in infection outcomes.

Specifically, our finding supports and extends the existing literature by demonstrating that DENV3 primary infections were significantly more severe and symptomatic compared with DENV1 and DENV2. 

In summary, these researchers wrote, "Using a high-throughput serotyping method to analyze inapparent primary DENV infections in a cohort over 17 years, our study enriches the epidemiological data landscape with unprecedented detail."

The unedited, full article is linked here.

Dengue is a vaccine-preventable disease, with various approved and candidate vaccines being investigated in October 2024.