RESUMO
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 7 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 5 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 9-16-year-old children from Puerto Rico. Finally, a full-scale evaluation was done with the 4 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 detecting anti-DENV IgG in early convalescent specimens with low cross-reactivity to 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.
RESUMO
Annually, over 2.5 billion people are at risk for infection with dengue virus (DENV), while between 50 and 100 million people contract the infection. There is an urgent need for alternative diagnostic tools that can detect DENV during acute infection. Recent studies have shown that DENV nonstructural protein 1 (NS1) is detectable in the blood as early as the onset of symptoms and persists well into the convalescent phase of the infection. We evaluated the utility of the Bio-Rad Platelia DENV NS1 antigen capture kit in combination with real-time reverse transcriptase PCR (RT-PCR) and an IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) for refining a new algorithm for the diagnosis of acute- or convalescent-phase DENV infection with a single clinical sample. We tested the Bio-Rad kit with three panels of sera. These panels were designed to evaluate the sensitivities of the NS1 kit for (i) early-convalescent-phase samples, (ii) acute-phase samples with false-negative PCR results, and (iii) IgM-negative convalescent-phase samples from patients with confirmed secondary DENV infections. Results show that NS1 can be detected in 22% of serum samples collected more than 10 days after the onset of illness and in 22% of samples that did not elicit an IgM response. Additionally, NS1 was detected in 37% of the tested acute-phase samples with false-negative PCR results, suggesting that NS1 detection may be valuable in increasing the sensitivity of current acute-phase diagnostics. These results will improve diagnosis with a single acute-phase or early-convalescent-phase sample for disease surveillance and clinical diagnosis.
