Expert Demoted After Questioning CDC’s Zika Test

Singleplex trumps Trioplex, lab chief says

The Centers for Disease Control and Prevention (CDC) is the scene of an intense internal debate about the best way to test whether someone has been infected with Zika virus, according to an article in the Washington Post. At the center of the controversy is Dr. Robert Lanciotti, one of the leading experts on the virus.

Lanciotti is chief of the CDC laboratory responsible for developing tests to diagnose viral diseases that are transmitted by mosquitoes, ticks, and fleas. In May, he was demoted after he raised concerns both inside and outside the agency about the CDC’s decision in the spring to recommend the new Trioplex test for Zika virus infection. That test is substantially less effective than another established test, he said, and misses nearly 40% of Zika infections. He also said the agency withheld information about testing differences from state and local public health laboratories.

Lanciotti was reinstated to his former position in July after he filed a whistleblower retaliation claim.

The questions raised by Lanciotti prompted an internal investigation by the CDC. In a report obtained by the Washington Post, the agency said it has made improvements that will boost the sensitivity of the Trioplex test. The internal investigation also found that the agency acted reasonably when it withheld conflicting test data from state public health labs.

The turmoil at the CDC illustrates the challenges of managing one of the world’s biggest public health crises at a time when the agency’s requests for emergency funding have been held up in Congress, according to the Post.

Determining whether someone has been infected with Zika is extremely difficult because most infected people don’t have symptoms. Moreover, many countries in South and Central America and in the Caribbean that were hard hit by Zika have also had outbreaks of two related viruses—dengue and chikungunya—that tests could confuse with Zika.

In March 2016, the FDA approved emergency use of the Trioplex test to detect Zika infection. Shortly afterwards, the CDC notified public health laboratories about the test and began shipping it.

Lanciotti compared the Trioplex test with the Singleplex assay, which he had developed in 2007. The Singleplex test detects genetic material up to seven days after the onset of illness.

Lanciotti found that the Trioplex assay missed 39% of Zika infections that were detected by his Singleplex test. An independent laboratory came to a similar conclusion. But a study by the CDC lab in Puerto Rico found no difference in sensitivity. CDC officials decided that the data showing a difference between the two tests were inconclusive.

Lanciotti continued using the Singelplex test at his own lab in Fort Collins, Colorado.

Source: Washington Post; September 27, 2016.