Novel Dengue Virus IgG Rapid Diagnostic Test Evaluated

The virus has five serotypes; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications. A number of tests are available to confirm the diagnosis including detecting antibodies to the virus or its RNA.

Scientists at Sanofi Pasteur (Lyon, France) tested their novel lateral flow immunoassay, OnSite Dengue immunoglobulin G (IgG) on blood samples that had been archived from participants aged 6 to 16 years in two phase three trials. Each serum sample was first tested using a plaque reduction neutralization test (both PRNT₉₀ and PRNT₅₀ levels) and an IgG ELISA for anti-nonstructural protein 1 (anti-NS1) to establish the baseline (pre-vaccination) dengue virus serostatus. A total of 346 blood samples tested seronegative for the dengue virus.

The investigators used all of these seronegative samples to evaluate the specificity of the rapid diagnostic test, and the results showed a specificity of 98.0%. For sensitivity, a random subset of 233 blood samples that were seropositive for dengue virus were used. The sensitivity of the rapid diagnostic test to be able to identify previous dengue virus infection status was found to be 95.3%.

Cross-reactivity of the rapid diagnostic test to Flaviviruses other than the dengue virus was also tested. For each type of Flavivirus tested, the samples used were seronegative for dengue virus but seropositive for the Flavivirus on a neutralization test or IgG ELISA, or the participant’s records showed prior vaccination against the Flavivirus. For this group, the rapid diagnostic test was found to be cross-reactive for the yellow fever virus in one blood sample (one cross-reactivity out of 42 samples that were seropositive for the yellow fever virus; 2.4%) and for Japanese encephalitis virus in one blood sample (1/36; 2.8%). For the blood samples displaying previous exposure to Zika virus (0/35) and the West Nile virus (0/32), the novel rapid diagnostic test had zero cross-reactivity.

Yasemin Ataman-Önal, PhD, from Sanofi Pasteur, said, “These findings support the use of this first-in-class point-of-care test to determine dengue serostatus and eligibility for dengue vaccination and because the tetravalent dengue vaccine is only indicated only for people who have had prior infection with the virus, pre-vaccination screening is necessary.” The study was presented at the Virtual 39th Annual Meeting of the European Society for Pediatric Infectious Diseases held 24-29 May, 2021.


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