Commercial test for Zika virus could be available within weeks
Liz Szabo, USA TODAY 2:12 p.m. EST February 12, 2016
A test to more easily diagnose the Zika virus could be available within weeks, not years, the World Health Organization said Friday.
Because Zika is a relatively new health concern, there are no commercially available tests for doctors to administer to their patients. Only labs at the Centers for Disease Control and Prevention and a handful of states currently are capable of diagnosing an infection.
An easy-to-use test would diagnose patients more quickly and help researchers monitor populations to determine whether the virus is spreading. That could speed up research, said Marie-Paule Kieny, assistant director-general for health systems and innovation at the WHO.
“Although it is difficult to predict the time for the first commercial and independently validated tests to be available, we are talking weeks and not years,” Kieny said.
Ten biotech companies are close to providing a Zika diagnostic test and 10 others are developing them, Kieny said. Some of the tests look for the virus in blood. Others measure the level of antibodies the body’s immune system makes in response to Zika.
Researchers in Houston hope to finish developing such a test for Zika by the end of February, said James Versalovic, a professor at Baylor College of Medicine, who is collaborating with scientists at Texas Children’s Hospital, Houston Methodist Hospital and Quest Diagnostics.
The test could be performed with blood, amniotic fluid, urine or spinal fluid, Versalovic said. “I think that we will see a large demand for testing,” he said. “Public health labs could be rapidly overwhelmed, so hospital and commercial labs must be ready soon to meet the demand for clinical testing.”
Versalovic said the test he’s developing could provide answers within three or four hours, although transportation time to and from labs could add a day or two to the wait.
There are no vaccines to prevent Zika. Officials at the National Institutes of Health said an early trial in humans could begin this year. Larger trials — the kind generally needed to get vaccines approved — are still 18 months away, Kieny said.
Although Zika infections usually provide only mild symptoms, or none at all, the WHO is concerned about a link between the outbreak in Brazil and a surge in birth defects there, making the disease a concern for pregnant women.
A fast test for Zika won’t answer all questions or relieve all worries, said Peter Hotez, dean of Baylor College of Medicine’s National School of Tropical Medicine in Houston.
Pregnant women worried about Zika could have an amniocentesis, a test in which doctors withdraw a small amount of the amniotic fluid that surrounds a fetus at 13 weeks of pregnancy. But doctors won’t be able to tell those women their chances of delivering a baby with birth defects, Hotez said.
Doctors don’t know what percentage of women with Zika infections will have a baby with birth defects because the link between the two is newly discovered. Officials first associated the virus with birth defects in Brazil only a few months ago.
Doctors can perform ultrasounds between the 24th and 28th weeks of pregnancy to try to determine if a fetus has microcephaly, Hotez said. However, many states don’t allow abortions that late in a pregnancy. That raises the question: “What do you do with the information?” Hotez said.
For the first time, the WHO is advising pregnant women to consult their doctors before traveling to places with Zika outbreaks and consider delaying travel. The CDC issued similar guidelines to American women last month. The WHO “is not recommending any travel or trade restrictions related to Zika virus disease” for the general public.
Zika is primarily spread by mosquito bites. Because it can sometimes spread through sex, the WHO said “until more is known about the risk of sexual transmission, all men and women returning from an area where Zika is circulating — especially pregnant women and their partners — should practice safe sex, including through the correct and consistent use of condoms.”