First Dengue Infection Can Be Just as Severe as Subsequent Ones, Indian Study Finds

A recent study published in Nature Medicine challenges the commonly held belief that severe cases of dengue fever are primarily associated with secondary infections. The research, conducted on a group of children in India, suggests that the first bout of dengue can be just as life-threatening as subsequent infections. Analysis revealed that over half of the severe dengue cases observed in the study were linked to primary infections rather than secondary ones.

In the last twenty years, dengue infections have surged in India, placing the country among the highest globally in terms of case numbers. Dengue patients are categorized into two groups: individuals encountering the infection for the first time, termed primary infections, and those who become re-infected after previous exposure, termed secondary infections.

The prevailing belief has been that only secondary infections pose significant risks, leading much of the research into vaccine development and treatment to focus on this group. An international team led by researchers at the New Delhi-based International Centre for Genetic Engineering and Biotechnology (ICGEB) has now found that it is not just the secondary infections but primary ones as well which can be severe and could jeopardise the life of the patients.

The discovery underscores the necessity to reassess the comprehension of dengue and the strategies implemented to combat the viral disease caused by the dengue virus (DENV), which is transmitted to humans through the bite of infected mosquitoes.

Dengue virus infection is a huge public health problem in India. Many patients develop severe disease that can also be sometimes fatal, said lead author of the study, Anmol Chandele, from ICGEB.

However, much of the ongoing vaccine intervention research is based on the currently widely held global belief that primary dengue infections are not usually dangerous and that the severe dengue disease is mainly due to secondary infections, Chandele said.

The study challenges the prevailing belief by demonstrating that primary infections account for a significant portion of severe dengue cases and fatalities. This revelation holds significant implications for public health, particularly in the development and implementation of effective and safe vaccine strategies to combat dengue.

The findings are pertinent not only within the Indian context but also on a global scale, given the continued worldwide spread of dengue viruses.Italy serves as a notable example of dengue's expansion, as indicated by a recent study involving Alessandro Marcello, the head of the ICGEB Molecular Virology laboratory at the Area Science Park in Trieste, Italy.