Utility of a multiplex real-time polymerase chain reaction for combined detection and serotyping of dengue virus in paediatric patients hospitalised with severe dengue: A report from Chennai.

Objective: Molecular detection and serotyping are rapid, sensitive and accurate techniques for early diagnosis of paediatric dengue. The present study evaluates multiplex real-time polymerase chain reaction (PCR) for diagnosis of dengue virus in children hospitalised with severe dengue (SD) and attempts to establish an association of clinical severity with specific serotypes.

Methods: Four hundred and eighty-five samples were received from hospitalised paediatric patients with suspected dengue from March 2019 to February 2020. Multiplex real time PCR was employed for diagnosis. An in-house real-time PCR that combined diagnosis and serotyping was established. Non-structural protein 1 (NS1) assay and real-time PCR were assessed for their accuracy in diagnosing severe paediatric dengue.

Results: Three hundred and twenty-five (67%) patients were positive for dengue RNA by real-time PCR. All four serotypes were identified throughout the year; dengue serotype 2 (DEN-2) was predominant (61%) followed by DEN-3, 20%. Compared to the commonly used NS1 testing, multiplex real-time PCR showed greater sensitivity in diagnosing SD.

Conclusions: Compared to NS1, multiplex real-time PCR is a rapid and accurate diagnostic test for children hospitalised with SD. DEN-2 was the predominant serotype in severe cases. Continued surveillance of serotypes should be carried out year-round in endemic areas.