Flu Breakthrough: The Search for a Universal Vaccine
Tired of having to get a different flu shot -- or two -- every year? Someday one shot may protect us against all the strains.
The 1918 Flu Pandemic continued...
Researchers have since discovered one reason the 1918 flu strain was so lethal. Unlike most of today's flu viruses, which can only copy themselves in the upper respiratory system (mouth, nose, and throat), the Spanish flu was able to replicate inside the lungs. As infected peoples' lungs filled with fluid, they suffocated to death, sometimes within a day or two of showing symptoms. While the H1N1 swine flu virus is also able to directly infect the lungs, researchers note that so far it has not been nearly as deadly as the Spanish flu.
Recently, researchers have discovered something else about that 1918 strain -- it's the genetic granddaddy of the H1N1 flu strain that's making headlines today. They traced the 2009 H1N1 virus back to the 1918 Cedar Rapids Swine Show in Iowa, where many pigs developed a respiratory infection that looked an awful lot like the influenza virus that was spreading like wildfire among humans. Over the next 90 years, that virus swapped genes a few times with other flu viruses, and re-emerged as the H1N1 flu strain we're dealing with today. The H1N1 flu strain circulating now is nowhere near as lethal as its predecessor, but unlike the H1N1 flu, it tends to be more dangerous to young people, and researchers think they've figured out why. Older people (particularly those born before 1950) have been exposed to the swine flu's relatives, and their bodies have built up antibodies to the virus. Young people don't have that same immunity.
The History of the Flu Shot
The 1918 pandemic was particularly vexing to doctors because they had nothing at their disposal to prevent or treat it. Researchers didn't even discover the influenza virus until 1933, and a working vaccine wasn't released until a decade later. Even today, with 21st century medical technology at our disposal, flu vaccination involves a lot of guesswork and uncertainty. Researchers from around the world have to look at flu surveillance reports several months in advance, anticipate which strain will be prevalent in the coming season, and hope their prediction is correct. They still haven't been able to create one vaccine that can target all strains for all seasons.