Three people in the District were wrongly told they did not have the Zika virus last year, and 26 others who may have been infected were mistakenly given a clean bill of health, according to the final accounting of results botched by the city’s public health lab, officials say.
At least one of the three who did not know she had the virus was pregnant at the time. She has since given birth, and the baby did not have microcephaly, the severe birth defect caused by Zika and characterized by an abnormally small head size and often an underdeveloped brain.
Several others who may have had the virus also were pregnant, the city has since said. But D.C. officials said Tuesday that since the women were told they were healthy, it remained unclear how many had gone without appropriate health care. The inconclusive results should have prompted intense screenings of the women and their babies before and after birth, according to federal guidelines.
In recent weeks, all 29 patients have been told of their new test results, D.C. officials said.
The disclosures Tuesday by the District’s public health lab revealed that dozens of families in the nation’s capital may have to wait a year or more to know if a child will develop symptoms of Zika. In addition to microcephaly, the virus can result in other defects that may not show up until a year after birth or longer, including hearing loss, irritability and difficulty swallowing, as well as cognitive, sensory and motor-skill problems.
The final tally also brings into focus the potential legal exposure the District could face because of the botched testing. Federal health officials have said the District appeared to be the only jurisdiction in the country to have mishandled the test.
The Washington Post reported in February that lab workers repeatedly overdiluted a solution used in the testing and also relied on a math formula entered incorrectly in a spreadsheet.
Combined, the errors skewed the results of tests conducted in 2016 on more than 400 D.C. residents and visitors whom doctors had deemed at high risk of having contracted the virus.
The lab’s new director, Anthony Tran, spotted some of the mistakes late last year and shut down the testing Dec. 14. All of the city’s Zika samples were shipped to other labs approved by the Centers for Disease Control and Prevention, a practice that continues.
Jenifer Smith, director of the D.C. Department of Forensic Sciences, which oversees the lab, said that after The Post detailed the breakdowns in an article Feb. 26, federal auditors visited the lab two days later and began investigating.
“We said, ‘Here was the mistake — the math was wrong; the dilution was incorrect.’ That’s where it got going,” Smith said.
In March, the auditors from the Centers for Medicare and Medicaid Services cited the lab for several deficiencies and gave the District 10 days to respond with planned improvements.
The lab, which also monitors for bioterrorism threats in the D.C. area, was allowed to keep its federal certification and continue operating. But it has rewritten its Zika testing procedures, retrained two technicians and passed a test showing that it can replicate results achieved at a federal lab, Smith said.
Smith said the lab plans to resume its own Zika testing within three months.
Smith said she wants to take an additional step of having her own advisory board review the changes and possibly to move to a new automated type of Zika testing that federal authorities approved last week.
“We kept our certification, we are back doing Zika testing on mosquitoes, and we will bring back the . . . test as soon as we can,” Smith said.
Zika is transmitted primarily through the bite of an infected mosquito, but it also can be passed through sex, even if the infected person shows no symptoms.
The debacle in the District also led to one nationwide change, Smith noted Tuesday in testimony before the D.C. Council’s judiciary committee. Federal auditors said a backup verification test should be conducted. Public health labs across the country now have been advised to conduct that extra test.
Council member Charles Allen (D-Ward 6), who chairs the committee, said he believes the episode will lead to “better Zika testing — and a better public health lab.”