Flu Virus

Scientists have identified one of the flu virus’ strengths, and may have found a way to use it against itself.

Researchers at the Icahn School of Medicine at Mount Sinai Medical Center say they’ve discovered that the flu virus can tell time.

The Flu Virus Life Cycle

The flu virus (the one you may be fighting right now) knows how long it should park itself in a cell to ensure it’s survival. It knows that if it leaves the cell too soon, it will be too weak to spread, but it can’t stick around for too long or your immune system will find and kill it.

It’s kind of like a turkey that knows just how long it should roast in the oven.

Benjamin tenOever, PhD, the Fishberg Professor of Microbiology at Mount Sinai, published these findings in Thursday’s issue of Cell Reports. Dr. tenOever and his team set out to determine how the virus can tell how much time it has to multiply, infect other cells, and move into another human host.

“We knew that the virus has about eight hours in a cell to create enough copies of itself to continue spreading before the cell's antiviral alarm would be set off,” Dr. tenOever said in a press release. “On a broader level, the virus needs two days of continuous activity to infect enough cells to permit spread to another human being. We wanted to tap into the flu's internal clock and find a way to dismantle it to prevent the spread of the virus.”

To better understand this, you have to know a bit about how the flu virus operates.

Kind of Like a Bank Robbery

The flu virus only has ten major components. Because it’s such a simple organism, it has to steal most of its resources from human cells in order to multiply. During this process, the immune system gets tipped off and sends reinforcements, like police responding to a bank robbery. 

Dr. tenOever hypothesized that the virus had what boiled down to a lookout used to determine when the immune system will charge in, sirens wailing. 

The Mt. Sinai team discovered a “quirk” in our cell biology that allows the virus to slyly and slowly collect a particular protein to help it escape the infected cell in time, spread to other cells, and infect everyone you work with. It does all this before the immune system can mount an attack. 

To continue the bank robbery analogy, the accumulated protein would be like the robbers discovering a master key in the bank vault that allows them to escape through the back door before any alarm is tripped.

Tripping Up the Virus

When researchers discovered the protein accumulation, they had an idea: they could force the virus out of the cell earlier by making it soak up the protein more quickly. It worked, and the virus couldn’t replicate.

Then, they made the protein absorption take longer than it normally would, giving the immune system enough time to respond. This allowed it to attack before the virus could escape and spread.

What This Means for the Future

The Mt. Sinai researchers hope their discovery of how the virus-protein relationship works will affect how new flu vaccines are designed and delivered.

Currently, there are two types of flu vaccination:

  • shot: the deactivated virus is injected into your body, causing your immune system to create flu-specific antibodies to fight it. There are three different vaccine strengths, depending on your age.
  • nasal spray: a live but weak flu virus is sprayed into your nose. The spray is approved for those ages 2 to 49, but not for pregnant women. 

The team hopes their research will lead to a new type of spray vaccine in which the live virus has a “defective clock,” with the goal of making vaccines safer for infants and the elderly.

What You Can Do Until Then

The Centers for Disease Control recommend that nearly everyone get a flu shot, especially since this year’s flu season has been extreme across the U.S.

Those who are most in need of a flu shot include:

  • pregnant women
  • children older than 6 months
  • people 65 and older
  • those with a compromised immune system
  • morbidly obese people
  • people at a high risk of developing serious complications like pneumonia
  • caregivers who could transmit the virus to high-risk people

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