What to Know
- Final retest results found three patients tested positive, 26 were inconclusive and 394 remained negative.
- DC's botched testing revealed the CDC's testing procedure was not CLIA compliant.
- Patients have been notified, and the CDC sent updated testing procedures to labs across the country.
Retests of 2016 Zika virus tests found three people tested positive for the virus in D.C., and last year's botched tests revealed the Centers for Disease Control's testing procedures did not meet requirements, according to the D.C. Department of Forensic Sciences.
A man, a woman and a pregnant woman have been told about their positive tests, and the CDC sent updated testing procedures to public health labs across the country.
The CDC's testing was "a 20th century test for a 21st century problem," DFS Director Jenifer Smith said. "Unfortunately, we need a better test. Right now, we don’t have access to that."
The CDC said the test developed by its Arboviral Diseases Branch, Division of Vector-Borne Diseases "measures antibodies that are made by the body in response to a virus, which are usually detectable when the virus is no longer present (shortly after symptoms begin and for a month or more thereafter)."
A federal audit found testing at D.C.'s Public Health Lab didn't comply with requirements of Clinical Laboratory Improvement Amendments, the federal regulatory standards for all clinical lab testing on humans, excluding trials and basic research. CLIA required an additional negative control be run, DFS said.
"We notified the CDC immediately, and they took about a week to notify all the other public health labs," Smith said.
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The CDC confirmed it updated its procedures to the more than 75 laboratories that use its test for Zika and similar viruses.
Even when following the updated procedures, the current tests supplied by the CDC are inadequate, Smith said.
"We are hopeful that the CDC will be providing a better method of testing, one that is more specific," Smith said.
In addition to the three people who retested positive after being told they tested negative last year, 26 patients' results came back inconclusive and 394 patients remained negative. The 26 patients who were inconclusive were notified.
Officials did not say anything about the impact on the pregnant woman's child.
D.C. had all specimens that tested negative between July and December retested by Centers for Disease Control and Prevention labs, the Department of Forensic Sciences said.
DFS hired Dr. Anthony Tran last year as director of its Public Health Laboratory, which handles all testing for the District. He had the laboratory's practices audited and learned of the flawed test, which was suspended Dec. 14. One of the problems was a mathematical error, he said.
DFS was approved to resume Zika testing March 10 but continues to send Department of Health approved samples to the CDC.
Zika is transmitted from infected mosquitoes to people and from pregnant mothers to babies. The virus usually causes a mild illness, but babies born to mothers with the virus can have microcephaly, a condition associated with small, undeveloped brains.
While the virus is not spread by casual human contact, health officials say it could be sexually transmitted.
D.C. tests mosquitoes for Zika and other viruses.
Zika remains a threat, experts say, and if there is an outbreak of the disease in the U.S. this summer, even a mild one, it would come with high costs.
According to a new study from Johns Hopkins, it could cost more than $183 million in medical expenses and lost productivity. If the outbreak is more severe, it could cost $1.2 billion or more.
While many people with Zika only have mild symptoms, if any, a Zika infection during pregnancy can cause severe birth defects.
For now, there is no treatment or vaccine to prevent Zika.