Solar eclipse presents first major test of power grid in renewable era

FILE PHOTO -- An array of solar panels are seen in Oakland, California, U.S. on December 4, 2016. REUTERS/Lucy Nicholson/File Photo

By Ruthy Munoz

HOUSTON (Reuters) – As Monday’s total solar eclipse sweeps from Oregon to South Carolina, U.S. electric power and grid operators will be glued to their monitoring systems in what for them represents the biggest test of the renewable energy era.

Utilities and grid operators have been planning for the event for years, calculating the timing and drop in output from solar, running simulations of the potential impact on demand, and lining up standby power sources. It promises a critical test of their ability to manage a sizeable swing in renewable power.

Solar energy now accounts for more than 42,600 megawatts (MW), about 5 percent of the U.S.’s peak demand, up from 5 MW in 2000, according to the North American Electric Reliability Council (NERC), a group formed to improve the nation’s power system in the wake of a 1964 blackout. When the next eclipse comes to the United States in 2024, solar will account for 14 percent of the nation’s power, estimates NERC.

For utilities and solar farms, the eclipse represents an opportunity to see how well prepared their systems are to respond to rapid swings in an era where variable energy sources such as solar and wind are climbing in scale and importance.

Power companies view Monday’s event as a “test bed” on how power systems can manage a major change in supply, said John Moura, director of reliability assessment and system analysis at the North American Electric Reliability Corp.

“It has been tested before, just not at this magnitude,” adds Steven Greenlee, a spokesman for the California Independent System Operator (CISO), which controls routing power in the nation’s most populous state.

CISO estimates that at the peak of the eclipse, the state’s normal solar output of about 8,800 MW will be reduced to 3,100 MW and then surge to more than 9,000 MW when the sun returns.

CISO’s preparation includes studying how German utilities dealt with a 2015 eclipse in that country. Its review prompted the grid overseer to add an additional 200 MW to its normal 250 MW power reserves.

“We’ve calculated that during the eclipse, that solar will ramp off at about 70 MW per minute,” said Greenlee. “And then we’ll see the solar rolling back at about 90 MW per minute or more.”

Power utilities say the focus will be on managing a rapid drop off and accommodate the solar surge post the eclipse. Utility executives say they do not expect any interruption in service, but are prepared to ask customers to pare usage if a problem arises.”We want to assure our customers that we have secured enough resources to meet their energy needs, even with significantly less solar generation on hand,” said Caroline Winn, chief operating officer at utility San Diego Gas & Electric Co.

In the Eastern United States, utilities will have more time to watch the results of their Western counterparts. PJM Interconnection, which coordinates electricity transmission among 13 states from Michigan to North Carolina, says non-solar sources such as hydro and fossil fuel can easily supplant the 400 MW to 2,500 MW solar loss, depending on the cloud cover.

For small-scale solar providers, the eclipse is a drop in the revenue bucket. Ron Strom, a North Carolina real estate developer, sells the power from a 58 kilovolt system atop a commercial property in Chapel Hill to Duke Energy.

“The event may cost me eighteen cents or thereabouts if my panels don’t produce solar for three hours,” said Strom.

(Additional reporting by Nichola Groom in Los Angeles; editing by Diane Craft)

Millions of Americans to gaze upon Monday’s once-in-a-lifetime eclipse

Millions of Americans to gaze upon Monday's once-in-a-lifetime eclipse

By Steve Gorman

(Reuters) – Twilight will fall at midday on Monday, stars will glimmer and birds will roost in an eerie stillness as millions of Americans and visitors witness the first total solar eclipse to traverse the United States from coast to coast in 99 years.

The sight of the moon’s shadow passing directly in front of the sun, blotting out all but the halo-like solar corona, may draw the largest live audience for a celestial event in human history. When those watching via broadcast and online media are factored into the mix, the spectacle will likely smash records.

“It will certainly be the most observed total eclipse in history,” astronomer Rick Fienberg of the American Astronomical Society (AAS) said last week.

The eclipse begins its cross-country trajectory over the Pacific Coast of Oregon in late morning. It will reach South Carolina’s Atlantic shore some 90 minutes later.

The total eclipse of the sun is considered one of the most spell-binding phenomena in nature but it rarely occurs over a wide swath of land, let alone one of the world’s most heavily populated countries at the height of summer.

In terms of audience potential, it is hard to top the United States, with its mobile and affluent population, even though the direct path is mostly over rural areas, towns and small cities. The largest is Nashville, Tennessee, a city of 609,000 residents.

Even so the advent of social media and inexpensive high-tech optics have boosted public awareness, assuring what many U.S. experts predict will be unprecedented viewership for the so-called “Great American Eclipse.”

Some might take issue with that prediction, citing a solar eclipse visible over parts of India, Nepal, Bangladesh and central China in July 2009. National Geographic estimated 30 million people in Shanghai and Hangzhou alone were in its path that day.

On Monday, the deepest part of the shadow, or umbra, cast by the moon will fall over a 70-mile-wide (113-km-wide), 2,500-mile-long (4,000-km-long) “path of totality” traversing 14 states. The 12 million people who live there can view the eclipse at its fullest merely by walking outside and looking up, weather permitting.

LIVESTREAMING AND PRICE-GOUGING

Some 200 million Americans reside within a day’s drive of the totality zone, and as many as 7 million, experts say, are expected to converge on towns and campgrounds along the narrow corridor for the event. Many are attending multi-day festivals featuring music, yoga and astronomy lectures.

Millions more could potentially watch in real time as the eclipse is captured by video cameras mounted on 50 high-altitude balloons and streamed online in a joint project between NASA and Montana State University. A partial eclipse will appear throughout North America.

Adding further to the excitement is the wide availability of affordable solar-safe sunglasses produced by the millions and selling so fast that suppliers were running out of stock.

The owner of one leading manufacturer reported price gouging by second-hand dealers who were buying up large supplies in and reselling them over the internet at a huge mark-up.

Not all the hoopla will unfold on dry land. Welsh pop singer Bonnie Tyler is slated to perform her 1983s hit single “Total Eclipse of the Heart” aboard a cruise liner as the vessel sails into the path of totality from Florida on Monday.

Back on the ground, forest rangers, police and city managers in the total eclipse zone are bracing for a crush of travelers they fear will cause epic traffic jams and heighten wildfire hazards.

“Imagine 20 Woodstock festivals occurring simultaneously across the nation,” Michael Zeiler, an AAS advisory panel member wrote on his website, GreatAmericanEclipse.com, referring to the famously chaotic 1969 outdoor rock extravaganza in upstate New York.

Zeiler, an avowed “eclipse chaser” who made the 650-mile (1,046 km) drive from his New Mexico home to Wyoming for a choice view, said South Carolina is likely to see the greatest influx as the destination state closest to the entire U.S. Eastern seaboard.

Monday’s event will be the first total solar eclipse spanning the entire continental United States since 1918 and the first visible anywhere in the Lower 48 states in 38 years.

The next one over North America is due in just seven years, in April 2024.

(Reporting by Steve Gorman in Los Angeles; Editing by Frank McGurty and Sandra Maler)

U.S. scientists able to alter genes of human embryos

Juan Carlos Izpisua Belmonte, Professor at Salk Institute's Gene Expression Laboratory and Jun Wu, Salk staff Scientist are pictured in this handout photo obtained by Reuters, August 2, 2017. Salk Institute/Handout via REUTERS

By Deena Beasley

U.S. scientists have succeeded in altering the genes of a human embryo to correct a disease-causing mutation, making it possible to prevent the defect from being passed on to future generations.

The milestone, reported in a paper released online August 2 in Nature, was confirmed last week by Oregon Health and Science University (OHSU), which collaborated with the Salk Institute and Korea’s Institute for Basic Science to use a technique known as CRISPR-Cas9 to correct a genetic mutation for hypertrophic cardiomyopathy.

Until now, published studies using the technique had been done in China with mixed results.

CRISPR-Cas9 works as a type of molecular scissors that can selectively trim away unwanted parts of the genome, and replace it with new stretches of DNA.

“We have demonstrated the possibility to correct mutations in a human embryo in a safe way and with a certain degree of efficiency,” said Juan Carlos Izpisua Belmonte, a professor in Salk’s Gene Expression Laboratory and a co-author of the study.

To increase the success rate, his team introduced the genome editing components along with sperm from a male with the targeted gene defect during the in vitro fertilization process. They found that the embryo used the available healthy copy of the gene to repair the mutated part.

The Salk/OHSU team also found that its gene correction did not cause any detectable mutations in other parts of the genome – a major concern for gene editing.

Still, the technology was not 100 percent successful. It increased the number of repaired embryos from 50%, which would have occurred naturally, to 74%.

The embryos, tested in the laboratory, were allowed to develop for only a few days.

“There is still much to be done to establish the safety of the methods, therefore they should not be adopted clinically,” Robin Lovell-Badge, a professor at London’s Francis Crick Institute who was not involved in the study, said in a statement.

‘UTMOST CAUTION’

Washington’s National Academy of Sciences (NAS) earlier this year softened its previous opposition to the use of gene editing technology in human embryos, which has raised concerns it could be used to create so-called designer babies. There is also a fear of introducing unintended mutations into germline cells.

“No one is thinking about this because it is practically impossible at this point,” Izpisua Belmonte said. “This is still very basic research … let alone something as complex as what nature has done for millions and millions of years of evolution.”

An international group of 11 organizations, including the American Society of Human Genetics and Britain’s Wellcome Trust, on Wednesday issued a policy statement recommending against genome editing that culminates in human implantation and pregnancy, while supporting publicly funded research into its potential clinical applications.

Salk’s Izpisua Belmonte, emphasizing that much more study is needed, said the most important practical application for the new technology could be in correcting genetic mutations in babies either in utero or right after they are born.

“It is crucial that we continue to proceed with the utmost caution, paying the highest attention to ethical considerations,” he said.

SOURCE: http://go.nature.com/2wm4g1v

Nature 2017.

(This story was refiled Refiling with source link at end of story and modifications throughout for professional readers)

First editing of human embryos carried out in United States

(Reuters) – Technology that allows alteration of genes in a human embryo has been used for the first time in the United States, according to Oregon Health and Science University (OHSU) in Portland, which carried out the research.

The OHSU research is believed to have broken new ground both in the number of embryos experimented upon and by demonstrating it is possible to safely and efficiently correct defective genes that cause inherited diseases, according to Technology Review, which first reported the news.

None of the embryos were allowed to develop for more than a few days, according to the report.

Some countries have signed a convention prohibiting the practice on concerns it could be used to create so-called designer babies.

Results of the peer-reviewed study are expected to be published soon in a scientific journal, according to OHSU spokesman Eric Robinson.

The research, led by Shoukhrat Mitalipov, head of OHSU’s Center for Embryonic Cell and Gene Therapy, involves a technology known as CRISPR that has opened up new frontiers in genetic medicine because of its ability to modify genes quickly and efficiently.

CRISPR works as a type of molecular scissors that can selectively trim away unwanted parts of the genome, and replace it with new stretches of DNA.

Scientists in China have published similar studies with mixed results.

In December 2015, scientists and ethicists at an international meeting held at the National Academy of Sciences (NAS) in Washington said it would be “irresponsible” to use gene editing technology in human embryos for therapeutic purposes, such as to correct genetic diseases, until safety and efficacy issues are resolved.

But earlier this year, NAS and the National Academy of Medicine said scientific advances make gene editing in human reproductive cells “a realistic possibility that deserves serious consideration.”

(Reporting By Deena Beasley; Editing by Michael Perry)

Giant iceberg breaks off Antarctica

FILE PHOTO: An aerial view of the rift in the Larsen C seen in an image from the Digital Mapping System over the Antarctica Peninsula, Antarctica, on November 10, 2016. NASA's Goddard Space Flight Center/Handout via REUTERS/File Photo ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY

By Nina Chestney

LONDON (Reuters) – One of the biggest icebergs on record has broken away from Antarctica, scientists said on Wednesday, creating an extra hazard for ships around the continent as it breaks up.

The one trillion tonne iceberg, measuring 5,800 square km, calved away from the Larsen C Ice Shelf in Antarctica sometime between July 10 and 12, said scientists at the University of Swansea and the British Antarctic Survey.

The iceberg has been close to breaking off for a few months. Throughout the Antarctic winter, scientists monitored the progress of the rift in the ice shelf using the European Space Agency satellites.

“The iceberg is one of the largest recorded and its future progress is difficult to predict,” said Adrian Luckman, professor at Swansea University and lead investigator of Project MIDAS, which has been monitoring the ice shelf for years.

“It may remain in one piece but is more likely to break into fragments. Some of the ice may remain in the area for decades, while parts of the iceberg may drift north into warmer waters,” he added.

The ice will add to risks for ships now it has broken off. The peninsula is outside major trade routes but the main destination for cruise ships visiting from South America.

In 2009, more than 150 passengers and crew were evacuated after the MTV Explorer sank after striking an iceberg off the Antarctic peninsula.

The iceberg, which is likely to be named A68, was already floating before it broke away so there is no immediate impact on sea levels, but the calving has left the Larsen C ice shelf reduced in area by more than 12 percent.

The Larsen A and B ice shelves, which were situated further north on the Antarctic Peninsula, collapsed in 1995 and 2002, respectively.

“This resulted in the dramatic acceleration of the glaciers behind them, with larger volumes of ice entering the ocean and contributing to sea-level rise,” said David Vaughan, glaciologist and director of science at British Antarctic Survey.

“If Larsen C now starts to retreat significantly and eventually collapses, then we will see another contribution to sea level rise,” he added.

Big icebergs break off Antarctica naturally, meaning scientists are not linking the rift to manmade climate change. The ice, however, is a part of the Antarctic peninsula that has warmed fast in recent decades.

“In the ensuing months and years, the ice shelf could either gradually regrow, or may suffer further calving events which may eventually lead to collapse – opinions in the scientific community are divided,” Luckman said.

“Our models say it will be less stable, but any future collapse remains years or decades away.”

(Editing by Toby Chopra)

U.S. muni market slowly starts paying heed to cyber risks

FILE PHOTO: An advertisement about the Microsoft Cybercrime Center plays behind a window reflecting a nearby building at the Microsoft office in Cambridge, Massachusetts, U.S. May 15, 2017. REUTERS/Brian Snyder/File Photo

By Hilary Russ

NEW YORK (Reuters) – A rise in cyber attacks on U.S. public sector targets so far has had little impact in the $3.8 trillion municipal debt market, with no issuer as yet hit by a downgrade or higher borrowing costs because of a cyber security threat.

That is beginning to change.

S&P Global has begun to quiz states, cities and towns about their cyber defenses, and some credit analysts are starting to factor cyber security when they look at bonds. Moody’s Investors Service is also trying to figure out how to best evaluate cyber risk.

The shift follows a particularly steep rise in ransomware attacks, when criminals hold an entity’s computer system hostage until a small ransom is paid.

The number of global ransomware detections rose 36 percent in 2016 from the year before, to 463,841, with the United States most heavily affected, according to cyber security firm Symantec Corp.

Such attacks, which have also hit companies and federal entities, have spared no kind of municipal issuer large or small, from police departments to school districts and transit agencies. Ransomware attacks on state and local governments and their agencies have risen in proportion with the overall increase, according to cyber insurance provider Beazley Group.

“State and local governments are a huge target, quite frankly an easy target for bad guys,” said Bob Anderson, managing director for information security at Navigant management consulting firm in Washington and a former global cyber investigator at the Federal Bureau of Investigation.

Last month’s “WannaCry” ransomware attack, which hobbled global businesses and Britain’s National Health Service, may also be prompting renewed focus on cyber security, though it had minimal impact in the United States.

Considering a potential cyber attack as a similar risk to a natural disaster, S&P has already been reviewing cyber security defenses of utilities, hospitals and colleges because they were early public sector targets for hackers.

Now it is also beginning to ask cities and states about the costs and level of security measures and the financial impact of successful attacks, said Geoffrey Buswick, who manages S&P’s public sector ratings.

HEAD IN THE SAND

The answers feed into broader categories that affect an issuer’s ratings, particularly governance, liquidity and operations.

Many breaches are handled quickly and financial damage is limited, but not every attack will necessarily end that way, Buswick said. “We’re trying to get sense of who has their head in the sand and who doesn’t.”

Fitch Ratings said it does not consider cyber security in its ratings, and many investors still are not concerned enough to ask for details.

In part, that is because it can be difficult to assess the operational and financial fallout of such attacks. Some high profile breaches so far have also done limited damage to issuers’ finances.

Case in point is the state of South Carolina, which in August 2012 suffered possibly the worst cyber attack yet of any city or state.

When hackers stole the personal data of more than 3.5 million taxpayers, the state had to investigate, provide credit monitoring and consumer fraud protection, and implement a slew of post-breach upgrades, according to State Senator Thomas Alexander.

The total cost is around $76 million and counting, he said. That is enough to pay for several school programs combined. But against South Carolina’s annual general fund budget of roughly $8 billion, the costs made no dent in its standing as a borrower.

Many issuers do not disclose any information to potential investors in bond documents about cyber risks or defenses. But a few, particularly hospitals and utilities, have started doing so.

In a February prospectus, the Maryland Health and Higher Educational Facilities Authority, the state’s largest public debt issuer, included nearly a full page devoted to the growing risk of cyber attacks.

“Because we’re such a large issuer, and because healthcare is often treated much more like a corporate credit, the legal counsels to the transaction weigh in on the bondholder risk section,” said Annette Anselmi, the authority’s Executive Director, noting that such disclosures also evolve depending on what kinds of questions the market is asking.

Hospitals are also ahead on cyber security disclosure because they rely on huge amounts of data, said Court Street Group analyst Joseph Krist.

Eventually, he expects others to follow suit.

“We went through this with getting munis to … disclose more pension information. Those were frankly long and painful processes. It just has to get to a critical mass.”

(Reporting by Hilary Russ; Additional reporting by Jim Finkle in Toronto; Editing by Daniel Bases and Tomasz Janowski)

Scientists develop fluid-filled artificial womb to help premature babies

An artists impression shows a lamb inside a fluid-filled womb-like bag known as an extra-uterine support device developed by the Children's Hospital of Philadelphia.MANDATORY CREDIT Children's Hospital of Philadelphia handout via REUTERS

By Kate Kelland

LONDON, (Reuters) – Scientists in the United States have developed a fluid-filled womb-like bag known as an extra-uterine support device that could transform care for extremely premature babies, significantly improving chances of survival.

In pre-clinical studies with lambs, the researchers were able to mimic the womb environment and the functions of the placenta, giving premature offspring a crucial opportunity to develop their lungs and other organs.

Around 30,000 babies in the United States alone are born critically early – at between 23 and 26 weeks of gestation, the researchers told reporters in a telephone briefing.

At that age, a human baby weighs little more than 500 grams, its lungs are not able to cope with air and its chances of survival are low. Death rates are up to 70 percent and those who do survive face life-long disability.

“These infants have an urgent need for a bridge between the mother’s womb and the outside world,” said Alan Flake, a specialist surgeon at the Children’s Hospital of Philadelphia who led the development of the new device.

His team’s aim, he said, was to develop an extra-uterine system where extremely premature babies can be suspended in fluid-filled chambers for a vital few weeks to bring them over the 28-week threshold, when their life chances are dramatically improved.

It could take up to another 10 years, but by then he hopes to have a licensed device in which babies born very prematurely are given the chance to develop in fluid-filled chambers, rather than lying in incubators being artificially ventilated.

“This system is potentially far superior to what hospitals can currently do for a 23-week-old baby born at the cusp of viability,” Flake said. “This could establish a new standard of care for this subset of extremely premature infants.”

The team spent three years evolving their system through a series of four prototypes – beginning with a glass incubator tank and progressing to the current fluid-filled bag.

Six preterm lambs tested in the most recent prototype were physiologically equivalent to a 23- or 24-week-gestation human baby and were able to grow in a temperature-controlled, near-sterile environment, Flake said.

The scientists made amniotic fluid in their lab and set up the system so that this flowed into and out of the bag.

Lung development in fetal lambs is very similar in humans, said fetal physiologist Marcus Davey, who worked on team.

“Fetal lungs are designed to function in fluid. We simulate that environment … allowing the lungs and other organs to develop while supplying nutrients and growth factors,” he said.

Flake said the success of the system, details of which were published on Tuesday in the journal Nature Communications, was due to its mimicking life in the uterus as closely as possible.

It has no external pump to drive circulation, because even gentle artificial pressure can fatally overload an underdeveloped heart, and there is no ventilator, because the immature lungs are not yet ready to breathe air.

Instead, the baby’s heart pumps blood via the umbilical cord into a low-resistance oxygenator that acts as a substitute for the placenta in exchanging oxygen and carbon dioxide.

Flake’s team plans to refine the system further and then downsize it for human infants, who are around a third of the size of the lambs used in the study.

(Editing by Tom Heneghan)

Waymo testing self-driving car ride service in Arizona

Waymo unveils a self-driving Chrysler Pacifica minivan during the North American International Auto Show in Detroit, Michigan, U.S., January 8, 2017. REUTERS/Brendan McDermid

SAN FRANCISCO (Reuters) – Alphabet Inc’s Waymo autonomous vehicle group will begin testing a self-driving car program for hundreds of families in Phoenix, Arizona and is buying 500 Chrysler minivans to do so, the companies said on Tuesday.

Waymo, which along with Google is owned by Alphabet Inc<GOOGL.O>, recently has been quietly testing the service for a handful of families, learning what potential customers would want from a ride service, the company said in a blog post.

It urged people to apply to take part in an expanded test, which is the first public trial of Waymo’s self-driving cars. The vehicles include human operators from Waymo behind the wheel, in case intervention is required and to take feedback.

Silicon Valley is racing to master self-driving technology, betting that it will transform the auto industry and be a gold mine for leading companies. Waymo has one of the best technology track records, and it has an alliance with Fiat Chrysler Automobiles <FCHA.MI>.

Many companies expect that customers will use autonomous vehicles as a service, rather than owning them outright. Ride service Uber in particular expects to use autonomous cars.

The new Waymo test in Arizona is meant to help the company understand what people want out of self-driving cars and see how they use and integrate the service. Testers will get access every day at any time.

Waymo already has with 100 Chrysler Pacifica minivans and is acquiring five times more, partly to be able to support the service.

(Reporting by Peter Henderson; Editing by Mary Milliken)

UK and Swedish watchdogs warn of international cyber attack

A magnifying glass is held in front of a computer screen in this picture illustration taken in Berlin May 21, 2013. REUTERS/Pawel Kopczynski

STOCKHOLM (Reuters) – A large-scale cyber attack from a group targeting organizations in Japan, the United States, Sweden and many other European countries through IT services providers has been uncovered, the Swedish computer security watchdog said on Wednesday.

The cyber attack, uncovered through a collaboration by Britain’s National Cyber Security Centre, PwC and cyber security firm BAE Systems, targeted managed service providers to gain access to their customers’ internal networks since at least May 2016 and potentially as early as 2014.

The exact scale of the attack, named Cloud Hopper from an organization called APT10, is not known but is believed to involve huge amounts of data, Sweden’s Civil Contingencies Agency said in a statement. The agency did not say whether the cyber attacks were still happening.

“The high level of digitalization in Sweden, along with the amount of services outsourced to managed service providers, means that there is great risk that several Swedish organizations are affected by the attacks,” the watchdog said.

The agency said those behind the attacks had used significant resources to identify their targets and sent sophisticated phishing e-mails to infect computers.

It also said Swedish IP addresses had been used to coordinate the incursions and retrieve stolen data and that APT10 specifically targeted IT, communications, healthcare, energy and research sectors.

(Reporting by Johan Ahlander; Editing by Niklas Pollard and Stephen Powell)

U.S. Zika vaccine begins second phase of testing

FILE PHOTO: A pair of Aedes albopictus mosquitoes are seen during a mating ritual while the female feeds on a blood meal in a 2003 image from the Centers for Disease Control (CDC). REUTERS/Centers for Disease Control/James Gathany/Handout via Reuters

By Julie Steenhuysen

CHICAGO (Reuters) – Researchers have begun the second phase of testing of a Zika vaccine developed by U.S. government scientists in a trial that could yield preliminary results as early as the end of 2017.

Dr. Anthony Fauci, director of the National Institutes of Allergy and Infectious Diseases (NIAID), said on Friday the $100 million trial has already been funded and will proceed, irrespective of the $7 billion in cuts to the National Institutes of Health (NIH) budget proposed by the Trump Administration over the next 18 months.

In a conference call with reporters, Fauci would not comment on the proposed cuts because it is not clear yet what the actual budget will be. Both Democratic and Republican lawmakers oppose cuts to the NIH, which funds 21 institutes, including NIAID.

NIH Director Dr. Francis Collins is scheduled to speak with President Donald Trump later on Friday. “I will certainly be talking to Francis Collins when he returns from the White House,” Fauci said.

Zika typically causes mild symptoms, but when the virus infects a pregnant women, she can pass it to her fetus, causing a variety of birth defects including microcephaly, in which the baby’s head is abnormally small.

Fauci said the current Zika vaccine candidate had cleared preliminary safety hurdles, and would now enter testing for efficacy, which would occur in two phases.

The first phase will continue testing for safety and evaluate the vaccine’s ability to stimulate the immune system to develop antibodies to fight Zika. It will also test different doses to see which works best.

The second phase, set to begin in June, will attempt to determine if the vaccine can actually prevent Zika infection.

Several companies are developing Zika vaccines, including Sanofi SA, GlaxoSmithKline Plc and Takeda Pharmaceuticals.

In the NIAID study, researchers aim to enroll at least 2,490 healthy volunteers in areas with confirmed or potential active transmission of Zika by mosquitoes. These include parts of the continental United States, Puerto Rico, Brazil, Peru, Costa Rica, Panama and Mexico. They will receive either the vaccine, or a placebo, and be followed for two years.

If enough people are exposed to the virus, Fauci said they could get an effectiveness signal as early as the end of this year. The trial is expected to be completed by 2019.

Fauci said the government is already in discussions with pharmaceutical companies that would share the costs of the final stage of testing and handle manufacturing.

Zika is primarily transmitted by mosquitoes, but it can also be transmitted sexually. According to Centers for Disease Control and Prevention, 5,182 people in the continental United States have been infected by Zika either locally or through travel to places where the virus is spreading. Another 38,303 cases have been reported in U.S. territories, including Puerto Rico.

(Reporting by Julie Steenhuysen; editing by Diane Craft)