Mon, Jul 24, 2017 | updated 06:12 PM IST

Vulnerability to type of flu virus is predicted by your birth year

Updated: Nov 12, 2016 14:13 IST      
Vulnerability to type of flu virus is predicted by your birth year

Washington D.C [USA], Nov. 12 (ANI): Falling ill due to animal-origin influenza virus?

According to a recent study, our birth year predicts how likely we are to get seriously ill or die in an outbreak of an animal-origin influenza virus.

Until now, it was believed that previous exposure to a flu virus conferred little or no immunological protection against new influenza viruses that can jump from animals to humans.

"Even a comparatively weak, mild pandemic flu event like the 2009 H1N1 (swine flu) outbreak is a trillion-dollar affair," said Michael Worobey. "A major pandemic like the one we saw in 1918 has the potential to kill large numbers of people and shut down the world's economy."

The research team studied two avian-origin influenza A ("bird flu") viruses, H5N1 and H7N9, each of which already has caused hundreds of spillover cases of severe illness or death in humans. Both strains are of global concern because they might at some point gain mutations that allow them not only to readily jump from birds into humans, but also spread rapidly between human hosts.

Analyzing data from every known case of severe illness or death from influenza caused by these two strains, the researchers discovered that whichever human influenza strain a person happened to be exposed to during his or her first infection with flu virus as a child determines which novel, avian-origin flu strains they would be protected against in a future infection. This effect of "immunological imprinting" appears to be exclusively dependent on the very first exposure to flu virus encountered in life -- and difficult to reverse.

When an individual gets exposed to flu virus for the first time, the immune system makes antibodies targeting hemagglutinin, a receptor protein shaped like a lollipop that sticks out from the virus surface. Like lollipops that come in different colors and flavors, influenza viruses differ from each other in the parts that make up their hemagglutinins. But each of the 18 known influenza A virus hemagglutinin subtypes falls into one of just two main "flavor" groups.

"In this analogy, let's say you were first exposed to a human 'orange lollipop' flu as a kid," Worobey said. "If later in life you encounter another subtype of flu virus, one from a bird and one that your immune system has never seen before but whose proteins also are of a similar 'orange' flavor, your chances of dying are quite low because of cross-protection. But if you were first infected with a virus from the 'blue lollipop' group as kid that won't protect you against this novel, 'orange' strain."

The results provide a functional explanation for a pattern that had vexed epidemiologists for a long time: Why are certain age groups more likely than others to suffer serious or even fatal complications from an infection with novel influenza strains?

"All sorts of possibilities have been put forth," Worobey said, "and here my colleagues from UCLA and I present a strong result showing that whatever other minor factors are at play, there is one really major one, and that is -- surprise, surprise -- we're not a completely blank slate when it comes to how susceptible we are to these emerging flu viruses. Even if we've never been exposed to H5 or H7 viruses, we have some kick-ass protection against one or the other."

All 18 subtypes of influenza A virus hemagglutinin circulate in non-human hosts, primarily birds. But only three -- H1, H2 and H3 -- have circulated in humans over the last century. Until now, there has been no way to predict which of the 18 subtypes might cause the next flu pandemic by successfully jumping from animals, and which age groups would be most at risk if this happened. The new study provides insights on both counts by revealing that immunological cross-protection appears to exist within each major branch of the evolutionary tree of influenza A. One branch includes human H1 and H2 viruses as well as avian H5, while the other includes human H3 and avian H7.

In the lollipop analogy, people born before the late 1960s were exposed to "blue lollipop" influenza as children (H1 or H2). The researchers found that these older groups rarely succumb to avian H5N1 -- which shares a "blue" hemagglutinin -- but often die from "orange" H7N9. People born after the late 1960s and exposed to "orange lollipop" influenza as children (H3) show the mirror-image pattern: They are protected from H7N9 but suffer severe disease and death when exposed to H5 viruses mismatched to their childhood exposure.

Based on previous work, Worobey thinks that a similar process may explain the unusual mortality patterns caused by the 1918 flu pandemic, which was more deadly among young adults.

"When I was finishing up that work and looking at the age patterns, I noticed something interesting," he said. "Those young adults were killed by an H1 virus, and from blood analyzed many decades later there is a pretty strong indication that those individuals had been exposed to a mismatched H3 as children and were therefore not protected against H1.

"The fact that we are seeing exactly the same pattern with current H5N1 and H7N9 cases suggests that the same fundamental processes may govern both the historic 1918 pandemic and today's contenders for the next big flu pandemic."

In their latest paper, Worobey and co-authors not only show that there is a 75 percent protection rate against severe disease and 80 percent protection rate against death if patients had been exposed to a matched virus as children, but also that one can take that information and make predictions about H5N1, H7N9 and other potential causes of future pandemics.

"If either of these viruses were to successfully jump from birds into humans, we now know something about the age groups that they would be hit the hardest," Worobey said, adding that efforts to develop a universal flu vaccine hinge on such insights because "such a vaccine would likely target the same conserved protein motifs on the virus surface that underlie this age-specific pattern."

Based on these findings, Worobey said future research should try to elucidate the exact mechanism underlying the immunological imprinting and finding out possible ways to modify it with a vaccine.

"In a way it's a good-news, bad-news story," he said. "It's good news in the sense that we can now see the factor that really explains a big part of the story: Your first infection sets you up for either success or failure in a huge way, even against 'novel' flu strains. The bad news is the very same imprinting that provides such great protection may be difficult to alter with vaccines: A good universal vaccine should provide protection where you lack it most, but the epidemiological data suggest we may be locked into strong protection against just half of the family tree of flu strains."

The study has been published in Science journal. (ANI)

New Delhi [India], July 24 (ANI): Toronto Recombinant Antibody Centre (TRAC) from the University of Toronto, Canada agreed to license MedGenome's patented cancer immunotherapy solution OncoPept to develop biomarkers for their drug candidates against immune modulators to treat cancer.

Full Story >>

Spitting out clues to 'ghost species' of ancient human

Updated: Jul 23, 2017 13:15 IST     

Washington D.C. [USA], Jul 23 (ANI): Ancient Africans may have engaged in a 'sexual rendezvous' with a 'ghost' species of archaic humans, according to a recent study.

Full Story >>

Water could propel satellites in future

Updated: Jul 22, 2017 15:55 IST     

New Delhi [India], July 22 (ANI): An Indian start-up foraying into space technology is coming up with a propulsion system for satellites known as Microwave Thruster, designed to run on water as fuel medium.

Full Story >>

3-D scanning complex objects with water

Updated: Jul 22, 2017 13:02 IST     

Washington D.C. [USA], Jul 22 (ANI): A team of computer scientists and engineers has brought next-gen 3-D scanning of complex objects closer to reality with the help of water.

Full Story >>

Now, a 'soft' robot that 'grows' like vine

Updated: Jul 21, 2017 12:33 IST     

Washington D.C. [USA], July 21 (ANI): A team of researchers has developed a robot that can navigate its environment by extending its reach.

Full Story >>

Our lifestyle choices turning Earth into 'plastic planet'

Updated: Jul 21, 2017 11:21 IST     

Washington D.C. [USA], Jul 21 (ANI): The 'Age of Plastic' is coming and if the pollution levels continue to rise, Earth will soon turn into a plastic planet.

Full Story >>

Washington D.C. [USA], Jul 21 (ANI): When it comes to decision-making, you may want to choose the wisdom of an ant over the folly of a grasshopper, according to a recent study.

Full Story >>

When Mars got photobombed by its moon Phobos

Updated: Jul 21, 2017 09:50 IST     

Washington D.C. [USA], Jul 21 (ANI): NASA's Hubble Space Telescope has captured Phobos, one of Mars' two moons, during its orbital trek around the Red Planet.

Full Story >>

New Delhi [India], July 20 (ANI): A team of Indian and French scientists have developed a touch sensitive material that enhances response rate by thousand times from existing materials.

Full Story >>

NASA's HERA XIII crew returns home to slumber

Updated: Jul 20, 2017 13:32 IST     

Washington D.C. [USA], Jul 20 (ANI): After 45 days in NASA's Human Exploration Research Analog (HERA), the four-man crew can hardly hold their eyes open.

Full Story >>

Washington D.C. [USA], Jul 20 (ANI): Until recently, invisibility cloaks and the like were firmly in the realms of science fiction, but now, you may soon be able to live out your wildest Harry Potter dreams.

Full Story >>

A secret to Elastigirl's powers: Magnets

Updated: Jul 20, 2017 10:39 IST     

Washington D.C. [USA], Jul 20 (ANI): If Plastic Man, Elastigirl and Mr Fantastic were to take up arms against Magneto, they'd be at a serious disadvantage, according to the latest research from Christian Binek.

Full Story >>

This is your brain on meditation

Updated: Jul 14, 2017 19:19 IST     

Oslo [Norway], Jul 14 (ANI): A team of researchers has shed some light on how meditation actually affects your brain.

Full Story >>

New Delhi [India], July 14 (ANI): Climate change is one of the biggest crises facing humanity

Full Story >>

Trouble reading smaller font? Turn to visual illusion

Updated: Jul 13, 2017 10:28 IST     

Washington D.C. [USA], Jul 13 (ANI): A recent study has found that exposure to a common visual illusion may enhance your ability to read fine print.

Full Story >>

Soon, watch 3-D movies at home sans glasses

Updated: Jul 13, 2017 10:27 IST     

Washington D.C. [USA], Jul 13 (ANI): A team of researchers is trying to bring glasses-free 3-D technology to your living room.

Full Story >>

A 'larger-than-Earth' sunspot is turning toward us

Updated: Jul 13, 2017 09:52 IST     

Washington D.C. [USA], Jul 13 (ANI): NASA's Solar Dynamics Observatory (SDO) has detected a massive sunspot, called Active Region 2665, that's bigger than Earth.

Full Story >>

When NASA's Juno stared right into Jupiter's angry red eye

Updated: Jul 13, 2017 09:26 IST     

Washington D.C. [USA], Jul 13 (ANI): The first ever close-up images of Jupiter's gargantuan hurricane, the Great Red Spot, have been revealed from NASA's Juno spacecraft after it completed its historic fly-by a few days ago.

Full Story >>

Antarctica just lost a 'Delaware-sized' iceberg!

Updated: Jul 13, 2017 07:49 IST     

Washington D.C. [USA], Jul 13 (ANI): A massive iceberg about the size of the state of Delaware split off from Antarctica's Larsen C ice shelf sometime between July 10 and July 12.

Full Story >>

London [UK], July 10 (ANI): Google Doodle, today, celebrates Swedish scientist Eva Ekeblad 293rd birthday.

Full Story >>