In the wake of mounting evidence connecting maternal Zika virus infections to microcephaly in babies, the World Health Organization (WHO) today strengthened its travel advice for pregnant women, and also offered new projections about the development of tools such as vaccines to battle the outbreak.
In other developments, the WHO also provided new details about recently reported Zika-related findings in several countries, including Guillain-Barre syndrome cases in South America, a sexual transmission case in Texas, and a microcephaly case in Hawaii.
Agency cautions pregnant women
The WHO's updated guidance urges pregnant women to consider avoiding travel to areas reporting local Zika virus transmission and to discuss travel plans with their doctors. The stepped-up recommendation brings the WHO's advice in line with travel advisories issued by several countries, such as the United States, Canada, and the United Kingdom.
However, the WHO emphasized that its advice doesn’t amount to a travel or trade restriction. It added that it based its shift in advice on the latest available evidence.
Today's guidance also warns travelers about the risk of sexual transmission, based on limited documented reports. Until more is known, the WHO said all men and women returning from Zika-hit areas—especially pregnant women and their partners—should practice safe sex, including consistent and correct use of condoms.
Research and development evolving rapidly
At a media briefing in Geneva today, Marie Paule-Kieny, PhD, the WHO's assistant director-general for health systems and innovation, said the WHO had already started work on a general plan for speeding up research and development in response to health emergencies, based on lessons learned in the Ebola outbreak, and it has been useful in visualizing the pathway for tools targeted to Zika virus.
In her introductory remarks, e-mailed to journalists, Kieny said research and development options are evolving rapidly and that at least 15 companies have been identified for possible vaccine development, most of them just beginning their work. The two products that are furthest along are a DNA vaccine from the US National Institutes of Health and an inactivated vaccine from India's Bharat Biotech.
Kieny said a lack of standardized animal models and reagents is slowing down development and that despite the encouraging picture, large-scale trials are still at least 18 months away.
For diagnostic tests, 10 companies with the capacity to develop nucleic acid or serologic tests have been identified so far, with 10 more companies at various stages of development, she said. Kieny pointed out that none of the tests have been independently validated or have received regulatory approval. The biggest task, she said, will be for companies to ensure an adequate reference method when generating their data, so that test performance can be assessed independently.
The need for validated, broadly available tests is urgent to enable research, clinical management, and surveillance, Kieney said. Though it's difficult to predict the availability timeline, "we're talking weeks and not years," she added.
As they did during the Ebola response, WHO's independent experts will gather to look at the vaccines and tests to see which ones seem most promising, she said. Meanwhile, the WHO is already working on "target product profiles" to identify the best characteristics for each tool, such as what type of vaccine would be best for women of childbearing age, Kieny said.
Regarding drugs, preventive therapies, similar to those for malaria, seem like a faster and more workable option than treatments, she said, adding that new vector control options also seem promising.
Zika findings from the US
In three separate statements today, the WHO provided more details on single microcephaly and sexual transmission cases in the United States, as well as puzzling increases in GBS in Venezuela and Colombia.
The microcephaly case involves a baby boy who was born in Hawaii in December to a mother who had experienced Zika virus symptoms during the second month of her pregnancy while living in Brazil.
Cerebrospinal fluid and serum samples collected from the boy within the first week after birth showed serologic evidence of Zika virus infection. Serum collected from his mother in the week after birth showed evidence of a recent flavivirus infection.
The WHO said the case adds to the growing literature on Zika virus and microcephaly, but so far a definitive link hasn't been established.
In its statement on the sexual transmission case in Texas, the WHO said the infected traveler had been in Venezuela at the end of December and first part of January. The patient's Zika symptoms began several days after returning to the United States.
On the day before symptom onset, the patient had sex with an individual who hadn't traveled. About 1 week later, that person's Zika symptoms started. Lab tests on samples from both patients were positive for Zika virus antibodies, and additional tests are underway. Weather conditions in the Dallas area didn't support mosquito populations at the time, and sampling in the area where the patients were from turned up no mosquitoes.
The WHO said sporadic cases of sexual Zika virus transmission have been reported, and that because mosquito bites are still the primary source of infection, the new sexual transmission report doesn't change its overall risk assessment.
GBS increases in South America
The WHO said today that Venezuela and Colombia in late January and early February notified it of increases in GBS cases.
In a 5-week period since the end of December, Colombia has reported 86 cases, three times as many as it would expect to see over the time period, based on patterns for the past 6 years. Initial reports suggested that all of Colombia's GBS cases—more than half the patients were male and most were adults—had symptoms compatible with Zika virus illness. However, the WHO said none of the cases were lab confirmed.
Meanwhile, Venezuela reported 252 GBS cases for the month of January, 66 of them in six cities in Zulia state. More than half the patients were older than 45 and 61% were male. About three quarters of the patients reported symptoms consistent with Zika virus infection before their neurologic symptoms began. Patients were treated with plasmapheresis or immunoglobulin, based on health ministry protocols.
The WHO said Zika virus infection was confirmed in only three GBS cases from Venezuela, one of which was fatal.
Similar GBS increases have been reported in other Zika-hit countries, especially Brazil and El Salvador, but so far the cause of the rises has not been established, the WHO said. It added that more studies are needed to explore the role of Zika or other infections that have been associated with GBS.
- Puerto Rican health officials and their partners at the US Centers for Disease Control and Prevention (CDC) today reported details on local Zika virus transmission in the territory in an early release from Morbidity and Mortality Weekly Report (MMWR). The first case was reported in an 80-year-old man who got sick on Nov 23, 2015. Puerto Rico has confirmed 29 more cases, most of them in the east or in the San Juan metropolitan area. The totals include a 37-year-old man with GBS symptoms and a pregnant woman who was diagnosed on Jan 22 in the first trimester of her pregnancy.
- A survey of US companies, universities, and nonprofit groups suggests that 38% would allow their female employees to defer travel to countries where Zika virus has been reported, Reuters reported today. The survey was conducted by the State Department's Overseas Security Advisory Council.
- Brazil's Evandro Chagas Institute has signed an agreement to develop a Zika virus vaccine with the University of Texas Medical Branch in Galveston, the Associated Press (AP) reported today, citing a Brazilian health ministry official. The report said the government is putting $1.9 million toward that project and is also exploring projects with the CDC and GlaxoSmithKline.
Feb 12 WHO updated travel advice
Feb 12 WHO press conference audiofile
Feb 12 WHO statement on Hawaii microcephaly case
Feb 12 WHO statement on GBS in Venezuela and Colombia
Feb 12 MMWR report on local Zika virus in Puerto Rico
Feb 12 Reuters story
Feb 12 AP story