GENEVA/PARIS/LONDON - The Zika virus could spread to Africa, Asia and Southern Europe, the World Health Organization said on Tuesday, as major French drugmaker Sanofi SA and others joined the race to create a vaccine.
A day after Geneva-based WHO declared an international public health emergency due to Zika’s association with the birth defect microcephaly in Brazil, the United Nations agency said it had launched a global response unit to fight the mosquito-borne virus that is spreading rapidly in Latin America.
Babies born with microcephaly have abnormally small heads and improperly developed brains.
“Most important, we need to set up surveillance sites in low- and middle-income countries so that we can detect any change in the reporting patterns of microcephaly at an early stage,” Dr. Anthony Costello said in Geneva. Costello is WHO’s director for maternal, child and adolescent health.
Twenty to 30 sites could be established worldwide, mainly in poor countries without robust health care systems.
The Pan American Health Organization said Zika was now spreading in 26 countries and territories in the Americas.
The virus was first identified in 1947 in rhesus monkeys in Uganda while scientists were studying yellow fever, according to the World Health Organization. It was identified in humans in 1952. Zika is spread by mosquitoes of the Aedes genus.
There is no vaccine or treatment for it.
Sanofi’s announcement marked the most decisive commitment yet by a major vaccine producer to fight Zika. The company said its Sanofi Pasteur vaccines division would use its expertise in developing vaccines for similar viruses such as yellow fever, Japanese encephalitis and dengue.
“Sanofi Pasteur is responding to the global call to action to develop a Zika vaccine, given the disease’s rapid spread and possible medical complications,” said Nicholas Jackson, research head of Sanofi Pasteur, who is leading the Zika vaccine project.
The WHO called for urgent development of better tests to detect the virus in pregnant women and newborn babies.
The new global response unit will build on lessons learned from West Africa’s Ebola crisis, Costello said. The WHO was criticized for a slow reaction to the Ebola epidemic, which killed more than 10,000 people.
“The reason it’s a global concern,” Costello said of Zika, “is that we are worried that this could also spread back to other areas of the world where the population may not be immune.”
Costello said Aedes aegypti mosquitoes that carry the Zika virus “are present … through Africa, parts of Southern Europe and many parts of Asia, particularly South Asia.” Africa and Asia have the world’s highest birthrates.
WHO Director-General Margaret Chan said on Monday it was “strongly suspected but not yet scientifically proven” that Zika causes microcephaly.
Costello, a pediatrician, said WHO was drafting guidelines for pregnant women and mustering experts to work on a definition of microcephaly that would include a standardized measurement of baby heads.
“We believe the association is ‘guilty until proven innocent,'” he said, referring to whether Zika causes microcephaly.
The WHO office for Southeast Asia, issued a statement urging countries in the region to “strengthen surveillance and take preventive measures against the Zika virus disease, which is strongly suspected to have a causal relation with clusters of microcephaly and other neurological abnormalities.”
Small biotech companies and academic institutions have plans to develop a Zika vaccine, and GlaxoSmithKline PLC has said it is concluding feasibility studies to see if its vaccine technology was suitable. And on Tuesday other companies joined the effort.
U.S. drug developer NewLink Genetics Corp., which is also developing an Ebola vaccine with Merck, said it has started a project to develop Zika treatment options.
The University of South Australia said it was working on a Zika vaccine with Australian biotech Sementis Ltd.
Experts have said a Zika vaccine for widespread use is months if not years away.
An Australian state health service said two Australians were diagnosed with the virus after returning from the Caribbean, confirming the first cases of the virus in the country this year.
Officials said mosquitoes carrying the virus had been detected at Sydney International Airport, but they said it was unlikely the virus would establish local transmission, given the lack of large numbers of the Aedes aegypti mosquitoes.
Brazil, which has 3,700 suspected cases of microcephaly that may be linked to Zika, is scheduled to host the Olympics in Rio de Janeiro in August.
Thailand played down the threat posed by Zika, and its public health ministry said the country should not worry about the virus. Thailand has confirmed one case of it this year.
Neighboring Malaysia and Singapore have said they are at high risk for the spread of Zika if the virus turns up in those countries.
The world is meanwhile once again asking scientists and drugmakers to come up rapidly with a vaccine for a viral disease that, in the latest case, few people had heard of until a few weeks ago, and even fewer feared.
Making a shot to generate an immune response against Zika virus, which is sweeping through the Americas, shouldn’t be too hard in theory. However, producing a safe, effective and deliverable product to protect women and girls who are at risk is not easy in practice.
For a start, scientists around the world know even less about Zika than they did about the Ebola virus that caused an unprecedented epidemic in West Africa last year.
Ebola, due to its deadly power, was the subject of bioterrorism research, giving at least a base for speeding up vaccine work. This time, the knowledge gap is more daunting.
There are just 30 mentions of Zika in patents, against 1,043 for Ebola and 2,551 for dengue fever, according to Thomson Reuters Derwent World Patents Index. And there have been only 108 high-profile academic papers on Zika since 2001, against more than 4,000 on Ebola, as found in the Web of Science.
Still, the U.S. National Institutes of Health, the Public Health Agency of Canada and the Butantan Institute in Brazil have started work on potential candidates for a Zika vaccine, and several biotech firms are in the race.
They include NewLink Genetics, which helped develop the first successful Ebola vaccine with Merck & Co.
Importantly, there is now a “big gun” vaccine maker with skin in the game: Sanofi said on Tuesday it will launch a Zika vaccine program, a day after the World Health Organization declared the disease and its suspected links to birth defects an international health emergency.
Canadian researcher Gary Kobinger told Reuters he believes an experimental Zika shot might be able to be used on a limited emergency basis as soon as late 2016, although full regulatory approval will take years.
Ben Neuman, an expert on viruses at Britain’s University of Reading, says there are many hurdles ahead. “To be useful, a Zika vaccine would need to be effective and safe, but it’s difficult to do both,” he told Reuters. “It’s a balancing act.”
That’s because a good vaccine works by provoking the immune system into a strong response — but not enough to make a person sick — and there is no simple way to assess the right immune response for Zika, according to one drug company expert.
Zika infection is so mild in the vast majority of cases that its victims are unaware they are even infected, so this group of potential patients is unlikely to need or want immunization.
The crucial target group is women who may be pregnant, since the disease’s greatest suspected threat is the possible link to severe birth defects.
All of this makes developing and testing a vaccine highly complex, especially since pregnant women are often excluded from clinical trials until the safety of new drugs or vaccines is well-established in other population groups.
It also makes for an uncertain and potentially limited market for any Zika vaccine.
Assuming Sanofi or another company succeeds in developing one, the vaccine may be used only in teenage girls — protecting them before they are likely to become pregnant — in countries and regions where Zika-carrying mosquitoes thrive.
“It’s a public health good initiative, it’s not necessarily a commercial initiative,” said Berenberg Bank analyst Alistair Campbell. “Zika is something that has cropped up suddenly and may well dissipate, so there may not be a sustainable annual cohort of patients for vaccination.”
Still, the WHO and other public health authorities will be relieved that one of the world’s top drugmakers has pledged to work on a vaccine.
GlaxoSmithKline is also investigating Zika and a spokeswoman reiterated on Tuesday it is concluding feasibility studies to see if its vaccine technology might be suitable.
Ultimately, developing vaccines is a question of priorities, as evidenced by a patchy pattern of protection against a range of mosquito-borne viruses over the past 80 years.
There was early success with the development in 1938 of the first vaccine against yellow fever, which belongs to the same virus family as Zika. More recently, drugmakers have successfully developed shots against Japanese encephalitis and dengue.
The first dengue vaccine, from Sanofi, was approved in December — after 20 years’ work.
Work on other mosquito-borne diseases such as West Nile fever and chikungunya is still underway.
One idea for tackling Zika is to adapt vaccine prototypes for dengue and West Nile, using them as a “platform” for the Zika virus. But even this approach would not be simple.
“For most viruses, there are lots of ways to make a somewhat effective vaccine, but the most effective vaccines target several parts of the virus in different ways,” said Neuman.
Multiple targets give the immune system more options, meaning more people are able to develop immunity. Yet an effective vaccine in most people may pack too much punch for others, with the potential to trigger birth defects.
“It’s big concern,” Neuman said. “And at this stage we just don’t know.”