Are viral loads in the febrile phase a predictive factor of dengue disease severity?
Authors: Dayarathna Shashika , Kuruppu Heshan , Silva Tehani , Gomes Laksiri , Shyamali N.L. Ajantha , Jeewandara Chandima , Ariyaratne Dinuka , Ramu Shyrar Tanussiya , Wijewickrama Ananda , Ogg Graham S. , Malavige Gathsaurie Neelika 
Published: August 2023

Background

As many studies have shown conflicting results regarding the extent of viraemia and clinical disease severity, we sought to investigate if viraemia during early dengue illness is associated with subsequent clinical disease severity.

Methodology/Principal Findings

424 adult patients, in whom the dengue virus (DENV) serotype could be identified, who presented within the first 4 days of illness, were recruited from a tertiary care hospital from Sri Lanka from September 2016 to September 2022 following informed written consent. To characterize subsequent clinical disease severity, all patients were followed throughout their illness daily and disease severity classified according to WHO 1997 and 2009 disease classification.

315 patients had DF, 109 progressed to develop DHF and of those 17 developed shock (DSS). Although the viral loads were higher in the febrile phase in patients who progressed to develop DHF than in patients with DF this was not significant (p=0.15). Significant differences were observed in viral loads in patients infected with different DENV serotypes (p=0.0001), with patients infected with DENV2 having the lowest viral loads and the highest viral loads in DENV1. Although those infected with DENV2 had lower viral loads, infection with DENV2 was significantly associated with a higher risk of developing DHF (p=0.016, Odds ratio 1.8; 95% CI 1.116 to 2.905). Based on the WHO 2009 disease classification, 268 had dengue with warning signs (DWW), 139 dengue without warning signs (DWoWS), and 17 had severe dengue (SD). No significant difference was observed in the viral loads between those with SD, DWW and DWoWS (p=0.34).

Conclusions/Significance

Viral loads in the febrile phase do not appear to significantly associate with subsequent clinical disease severity in a large Sri Lankan cohort.

Author summary

As many studies have shown conflicting results regarding the extent of viraemia and clinical disease severity, we sought to investigate if viraemia during early dengue illness was associated with subsequent clinical disease severity. We assessed the viral loads and subsequent clinical disease severity in 424 patients, during early illness, to determine if viral loads associate with disease subsequent disease severity. Although the viral loads were higher in early illness in patients who progressed to develop dengue haemorrhagic fever (DHF) than in patients with dengue fever, this was not significant. Significant differences were observed in viral loads in patients infected with different DENV serotypes, with patients infected with DENV2 having the lowest viral loads and the highest viral loads in DENV1. Although those infected with DENV2 had lower viral loads, infection with DENV2 was significantly associated with a higher risk of developing DHF. Therefore, viral loads in early illness, do not appear to strongly associate with subsequent clinical disease severity in this Sri Lankan cohort.