Comparison of the sensitivity and specificity of commercial anti-dengue virus IgG tests to identify persons eligible for dengue vaccination.

The Advisory Committee on Immunization Practices (ACIP) recommended that dengue pre-vaccination screening tests for Dengvaxia administration have at least 98% specificity and 75% sensitivity. This study evaluates the performance of commercial anti-DENV IgG tests to identify tests that could be used for pre-vaccination screening. First, for seven tests, we evaluated sensitivity and specificity in early convalescent dengue virus (DENV) infection, using 44 samples collected 7-30 days after symptom onset and confirmed by RT-PCR. Next, for the five best-performing tests and two additional tests (with and without an external test reader) that became available later, we evaluated performance to detect past dengue infection among a panel of 44 specimens collected in 2018-2019 from healthy 9- to 16-year-old children from Puerto Rico. Finally, a full-scale evaluation was done with the four best-performing tests using 400 specimens from the same population. We used virus focus reduction neutralization test and an in-house DENV IgG ELISA as reference standards. Of seven tests, five showed ≥75% sensitivity in detecting anti-DENV IgG in early convalescent specimens with low cross-reactivity to the Zika virus. For the detection of previous DENV infections, the tests with the highest performance were the Euroimmun NS1 IgG ELISA (sensitivity 84.5%, specificity 97.1%) and CTK Dengue IgG rapid test R0065C with the test reader (sensitivity 76.2% specificity 98.1%). There are IgG tests available that can be used to accurately classify individuals with previous DENV infection as eligible for dengue vaccination to support safe vaccine implementation. IMPORTANCE: The Advisory Committee on Immunization Practices (ACIP) has set forth recommendations that dengue pre-vaccination screening tests must exhibit at least 98% specificity and 75% sensitivity. Our research rigorously assesses the performance of various commercial tests against these benchmarks using well-characterized specimens from Puerto Rico. The findings from our study are particularly relevant given FDA approval and ACIP recommendation of Sanofi Pasteur's Dengvaxia vaccine, highlighting the need for accurate pre-vaccination screening tools.

Expression of recombinant dengue virus type 1 non-structural protein 1 in mammalian cells and preliminary assessment of its suitability to detect human IgG antibodies elicited by viral infection.

In recent years dengue has become a rapidly growing public health problem worldwide, however, the availability of accurate and affordable diagnostic immunoassays is limited, partly due to the difficulty of producing large quantities of purified antigen. Non-structural protein 1 (NS1) has shown to be a good candidate for inclusion in diagnostic assays and for serosurveys, particularly in endemic countries as a prerequisite for vaccination. In this work the NS1 antigen derived from dengue virus type-1 (DENV1) was expressed in HEK293-T cells and purified by affinity chromatography. The recombinant protein was recovered properly folded as dimers, highly purified and with good yield (1.5 mg/L). It was applied as a serological probe in an indirect ELISA developed in this work to detect human IgG antibodies. Preliminary comparative performance values of 81.1% sensitivity and 83.0% specificity of the developed and preliminary validated iELISA, relative to a commercial kit were obtained, suggesting that the purified recombinant DENV1 NS1 antigen is suitable to detect IgG antibodies, indicative of past DENV infection.