WHO warns Zika to spread across Americas, Glaxo on hunt for vaccines
by Daily Sabah with Reuters
GENEVA / LONDONJan 25, 2016 - 12:00 am GMT+3
by Daily Sabah with Reuters
Jan 25, 2016 12:00 am
The mosquito-borne Zika virus, which has been linked to brain damage in thousands of babies in Brazil, is likely to spread to all countries in the Americas except for Canada and Chile, the World Health Organization said on Monday as GlaxoSmithKline Plc announced that it is evaluating whether its vaccine technology is suitable for the deadly virus.
Zika has not yet been reported in the continental United States, although a woman who fell ill with the virus in Brazil later gave birth to a brain-damaged baby in Hawaii.
Brazil's Health Ministry said in November that Zika was linked to a fetal deformation known as microcephaly, in which infants are born with smaller-than-usual brains.
Brazil has reported 3,893 suspected cases of microcephaly, the WHO said last Friday, over 30 times more than in any year since 2010 and equivalent to 1-2 percent of all newborns in the state of Pernambuco, one of the worst-hit areas.
The Zika outbreak comes hard on the heels of the Ebola epidemic in West Africa, demonstrating once again how little-understood diseases can rapidly emerge as global threats.
"We've got no drugs and we've got no vaccines. It's a case of deja vu because that's exactly what we were saying with Ebola," Trudie Lang, a professor of global health at the University of Oxford, said on Monday. "It's really important to develop a vaccine as quickly as possible."
Large drugmakers' investment in tropical disease vaccines with uncertain commercial prospects has so far been patchy, prompting health experts to call for a new system of incentives following the Ebola experience.
"We're concluding our feasibility studies as quickly as we can to see if our vaccine technology platforms might be suitable for working on Zika," Glaxo spokeswoman Anna Padula said in an email. She declined to provide details but added that vaccine development typically takes 10 to 15 years.
The Sao Paulo-based Butantan Institute is currently leading the research charge on Zika and said last week it planned to develop a vaccine "in record time", although its director warned this was still likely to take three to five years.
France's Sanofi SA, which won approval late last year for the first dengue vaccine, has said it is reviewing the possibility of applying its technology for Zika.
"However, there are too many unknowns about Zika to reliably judge the ability to research and develop a vaccine effectively," a spokesman said in an email in early January.
Japan's Takeda Pharmaceutical Co Ltd said last week it was entirely focused on addressing dengue, and that its experimental vaccine was not designed to cover Zika.
Executives at Merck & Co Inc, which will likely be one of the first developers of an Ebola vaccine, were not immediately available to comment on any plans for Zika.
The virus was first found in a monkey in the Zika forest near Lake Victoria, Uganda, in 1947, and has historically occurred in parts of Africa, Southeast Asia and the Pacific Islands. But there is little scientific data on it and it is unclear why it might be causing microcephaly in Brazil.
Laura Rodrigues of the London School of Hygiene and Tropical Medicine said it was possible the disease could be evolving.
If the epidemic was still going on in August, when Brazil is due to host the Olympic Games in Rio de Janeiro, then pregnant women should either stay away or be obsessive about covering up against mosquito bites, she said.
The WHO advised pregnant women planning to travel to areas where Zika is circulating to consult a healthcare provider before traveling and on return.
The clinical symptoms of Zika are usually mild and often similar to dengue, a fever which is transmitted by the same Aedes aegypti mosquito, leading to fears that Zika will spread into all parts of the world where dengue is commonplace.
More than one-third of the world's population lives in areas at risk of dengue infection, in a band stretching through Africa, India, Southeast Asia and Latin America.
Zika's rapid spread, to 21 countries and territories in the Americas since May 2015, is due to the prevalence of Aedes aegypti and a lack of immunity among the population, the WHO said in a statement.
RISK TO GIRLS
Like rubella, which also causes mild symptoms but can lead to birth defects, health experts believe a vaccine is needed to protect girls before they reach child-bearing age.
Evidence about other transmission routes, apart from mosquito bites, is limited.
"Zika has been isolated in human semen, and one case of possible person-to-person sexual transmission has been described. However, more evidence is needed to confirm whether sexual contact is a means of Zika transmission," the WHO said.
While a causal link between Zika and microcephaly has not yet been definitively proven, WHO Director-General Margaret Chan said the circumstantial evidence was "suggestive and extremely worrisome".
In addition to finding a vaccine and potential drugs to fight Zika, some scientists are also planning to take the fight to the mosquitoes that carry the disease.
Oxitec, the UK subsidiary of U.S. synthetic biology company Intrexon, hopes to deploy a self-limiting genetically modified strain of insects to compete with normal Aedes aegypti.
Oxitec says its proprietary OX513A mosquito succeeded in reducing wild larvae of the Aedes mosquito by 82 percent in an area of Brazil where 25 million of the transgenic insects were released between April and November. Authorities reported a big drop in dengue cases in the area.