At a time when the world is is once again asking scientists and drugmakers to come up rapidly with a vaccine for Zika virus, scientists from a Hyderabad laboratory have claimed that they have developed world's first vaccine against the virus.

At a time when scientists and drugmakers are trying to formulate a vaccine for the Zika virus, scientists from a Hyderabad laboratory have claimed that they have developed the world's first vaccine against the virus. According to NDTV, the scientists have developed two vaccines using a live Zika virus imported officially.

The virus, linked to severe birth defects in thousands of babies in Brazil, is spreading rapidly in the Americas, and WHO officials have expressed concern that it could hit Africa and Asia as well.

Bharat Biotech International Limited in Hyderabad told NDTV that they have patented the vaccine. "On Zika, we are probably the first vaccine company in the world to file a vaccine candidate patent about nine months ago," said Dr Krishna Ella, Chairman and Managing Director, Bharat Biotech Ltd.

According to Dr Ella, the Hyderabad-based lab can make one million doses of the vaccine in four months and Prime Minister Narendra Modi has been requested to help fast-track the process "cutting through the red tape of regulatory clearances".

"We believe we have an early mover advantage in developing the Zikavac and we are probably the first in the world to file for global patent for Zika vaccine candidates.

"We have two candidate vaccines in development. One of them is an inactivated vaccine that has reached the stage of pre-clinical testing in animals," Ella said.

Quoting a WHO report, he said Zika is now present in 23 countries and Brazil, the hardest-hit country, has reported around 3,530 cases of the devastating birth defect, called microcephaly, in 2015 that are strongly suspected to be related to Zika.

"We hope to announce the arrival of Zikavac to the world as early as possible," he said.

"Considering that women of child-bearing age and pregnant women are the prime target group for Zika virus vaccine, we consider safety as the overriding factor in development of a new vaccine for this virus. The vaccine methods developed early on, before the devastating consequences of the epidemics in Brazil came to light provided us a push to accelerate vaccine development," Dr Sumathy, Director, R&D, Bharat Biotech said.

Currently, Dr Sumathy is focusing towards scale up and characterisation of the vaccine product, Ella further said.

Brazil's president, noting there is no medical defense against the infection, called for a crusade against the mosquitoes spreading it. "As long as we don't have a vaccine against Zika virus, the war must be focused on exterminating the mosquito's breeding areas," said President Dilma Rousseff.

The Zika virus was first discovered in Africa in 1947. But until last year, when it was found in Brazil, it had never been a threat in the Western Hemisphere.

The virus causes no more than a mild illness in most people. But there is mounting evidence from Brazil suggesting infection in pregnant women is linked to abnormally small heads in their babies — a birth defect called microcephaly.

India itself may not be as safe as hoped. According to India Today, India has been free of this virus for over 60 years, and that traces of Zika were last seen in 1952-53.

However, Hindustan Times reported that the Union health ministry is procuring testing kits to detect the virus, which is spread by the bite of the Aedes aegypti mosquito — the same vector that spreads dengue and chicken guinea. "The government is also writing to the Centers for Disease Control and Prevention (CDC) to know more about the infection and prepare accordingly,” the report quoted a senior official from the Zoonosis unit of the Union health ministry as saying. Furthermore, the report added that the ministry is putting together protocols to track the 'sudden rise' of birth defects across the country.

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 US 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 programme, 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 immunisation.

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.

Clinical Trials

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."

With inputs from agencies