The World Health Organization (WHO) said today that it has convened its Zika virus emergency committee for the second time, with the group meeting tomorrow to review the quickly evolving scientific developments related to suspected birth defects and neurologic complications.
Meanwhile, a 3-day WHO-led Zika virus countermeasure meeting began in Geneva this week, and health officials in the Philippines are investigating possible local spread of the virus.
Emergency committee eyes new data
The WHO's Zika virus emergency committee met for the first time 5 weeks ago, which led to a public health emergency declaration on Feb 1 based on the disease's suspected microcephaly and neurologic complications, including Guillain-Barre syndrome (GBS).
Since then, scientific evidence for a link between the conditions has grown stronger, a trend that prompted the group to meet again. For example, a case-control study published last week showed a strong connection between the virus and GBS in French Polynesia's 2013-14 outbreak. And a few days later Brazilian researchers published a cohort study of infected pregnant women, many of whom delivered babies who had birth defects.
WHO emergency committees usually meet every 3 months, or earlier as developments warrant. The WHO said in a media advisory that the committee, which will meet via teleconference and also assess its earlier recommendations and if the precautionary steps should be strengthened or modified.
The panel expects to hold a media briefing at the end of the deliberations to announce any changes to its earlier public health emergency of international concern declaration.
The WHO has also slated a media briefing on Mar 9 at the end of the Zika countermeasure meeting to share details about what drugs, vaccines, and diagnostic tests seem most promising.
Promising mouse study
In a related development, BioCryst Pharmaceuticals, based in Research Triangle Park, N.C., today announced promising findings in mice experimentally infected with Zika virus for its broad-spectrum antiviral, BCX4430. In a statement today the company said it would present the findings at the WHO countermeasure meeting that's under way in Geneva.
The trial at Utah State University involved immune-deficient mice, with the researchers comparing intramuscular BCX4430 injections at two different dose levels against ribavirin and placebo control groups. At both BCX4430 dose levels, median survival was superior to both control groups. For the standard dose, mice survived a median of more than 28 days. Survival for the low-dose group was 23 days, compared with 14 and 17 days for the control groups.
The drug is in phase 1 human trials to gauge its safety, and it is being studied for use against a host of other viral pathogens, including Ebola, Marburg, and yellow fever.
Philippines probes possible local spread
Health officials in the Philippines are investigating the possibility of local Zika virus spread after an infection was confirmed in an American woman after she spent 4 weeks in the country in January, Agence France-Presse (AFP) reported yesterday, citing Philippines health secretary Janette Garin.
Garin said the US Centers for Disease Control and Prevention said the woman had symptoms during her last week in the Philippines. She added that the countries are collecting information on the patient and where she traveled during her stay in the Philippines.
The only other known Zika case in the Philippines was reported in 2012 in a 15-year-old boy, according to the AFP report.
Role of placenta, Colombia study, transmission reports
- The placenta may play different or a combination of roles in the development of Zika-related microcephaly, researchers from the University of Pennsylvania and the University of Texas said in a Mar 4 hypothesis piece in The Lancet. They said the placenta could directly pass the virus to the early embryo or fetus or it could mount its own response to Zika virus exposure, which could also cause brain defects. They said as more data are collected, either or both hypotheses might prove true.
- Colombian researchers, in a Mar 4 letter to Travel Medicine and Infectious Disease, reported initial clinical and lab findings from a cohort of 28 pregnant women who are being followed after having confirmed Zika virus infections. Zika virus has been circulating in the areas the women were recruited from since the last 3 months of 2015. Twenty-one of them had symptoms during pregnancy, most of which were mild. Thirteen of the women were infected during their first or second trimesters. So far none of the women have delivered their babies. Fetal ultrasounds in two women suggest brain calcifications, and amniocentesis is planned for those two.
- The WHO today issued a statement on two likely cases of sexual Zika virus transmission, an case first announced by France's health ministry on Feb 28 and a case from Argentina first noted in the WHO's Zika situation update on Mar 4. For the French case, serology tests are under way and a pregnancy test was negative. Argentina's case involved a man from Cordoba province who got sick after traveling to Colombia and apparently passed the virus to his female partner. Samples are still being tested, and the transmission mode is still being investigated, especially since the province is experiencing a dengue outbreak, though officials say sexual transmission is likely.
- Also, the WHO recently fleshed out details of the first two local transmission cases reported in the Dutch territory Sint Maarten. In a Mar 4 statement, it said the cases involve a resident and a tourist whose illnesses were confirmed Feb 12 and 18. The patients aren't related and had spent their incubation in Sint Maarten, though they had visited the neighboring island Anguilla for less than 24 hours.
Feb 1 CIDRAP News story "WHO issues Zika health emergency over complications"
Mar 7 BioCryst press release
Mar 6 AFP story