New Zika test boasts speed, high specificity

A Brazilian-designed test shows great potential in identifying Zika, being capable of discriminating it from dengue infections with high accuracy, while doing so with an estimated cost of just $3 – $3.70 per patient.

The test detects antibodies against Zika virus in samples of blood serum, providing a low risk of cross-reaction with related microorganisms. It was designed by the technology firm Inovatech, with support from the São Paulo Research Foundation and scientists at the University of São Paulo’s Biomedical Science Institute, as well as the Butantan Institute.

“We’re in the final stages of developing a serological test to detect immunoglobulin G (IgG) antibodies, which remain in the organism for many years after infection, providing lifelong immunity,” said Danielle Bruna Leal de Oliveira, a researcher at ICB-USP’s Clinical & Molecular Virology Laboratory and principal investigator for the project. “We expect it to be approved for sale in the second half of this year.”

The test provides a critical forward step for further Zika preparations. It will allow responders a greater ability to determine the exact size of outbreaks, the proportion of pregnant women infected and the risk to women for giving birth to babies with neurological problems — a major concern with those infected by Zika.

“The idea is to include this test in the prenatal examination process,” Oliveira said. “If we can do that, pregnant women with a negative result [meaning they have never been infected] will take more precautions, such as avoiding travel to high-risk areas and using insect repellent. Meanwhile, those who are immune will be able to stop worrying.”

Current tests, according to Oliveira, either only work in the acute phase of infection or detect Zika antibodies with low specificity. That specificity works out to between 69 percent to 75 percent, leaving a quarter’s room for false positives, against the new test’s 93 percent specificity.

The test takes about three hours currently to complete.