In a report presented by the newest issue of the journal Nature, scientists offer a new perspective on how time affects or not the human immune system. According to the study, people who made it through the 1918 H1N1 flu crisis that caused the death of more than 50 million people worldwide, are still developing antibodies.

The tests were conducted by researcher Dr. James E. Crowe Jr., professor of pediatrics, microbiology and immunology at Vanderbilt University. He studied blood samples from 32 people born before 1915 and found that every single one of them presented antibodies to the 1918 flu virus and some of them were still producing them.

"Most people have a notion that elderly people have very weak immunity or they have lost immunity […] This study shows that extremely elderly people have retained memory of being infected with the 1918 flu, even 90 years later," Dr. Crowe explained.

He talked about the antibodies, which present an extremely high potency, grabbing on tightly to the virus and never letting it go.

The discovery is expected to help with a series of other tests on new pandemic viruses and the team involved believes that the extended work with the elderly will prove to be extremely useful, as the human body has the ability to keep its immunity to problems encountered in the past, and the tests might bring out important details about other issues. Also, it shows that with a little more work, scientists will be able to develop long lasting vaccines and antibody treatments for any sort of menacing viruses that might surface in the future.

One of the theories behind the study belongs to Dr. Marc Siegel, an associate professor of medicine at New York University School of Medicine in New York City, who believes that in order to have developed such a strong immune system, the people may have encountered a less powerful strain of flu before 1918, which prepared them for successfully dealing with 1918’s situation.

"The implication of this study is the 1918 virus was so powerful that the immunity you had to have in order to survive was so prominent that it lasted for the rest of your life," Siegel explained.  He also added: "So, those in certain age groups who had seen a related virus had the strongest responses. Either they died, or they developed a profound immune response."

Looking back at the catastrophic outcome of the epidemic, scientists and doctors fear that a similar crisis situation might be triggered again and their efforts are focused on covering every aspect and getting ready for such a scenario.

The Spanish flu outbreak of 1918 appeared at the end of World War One, affecting anyone from children to healthy adults. Many believe that the victims’ number closed in on 100 million. At the time, it was estimated that more than 3 percent of the human population was killed and around 20 percent of the population suffered from the disease. It is considered by far the most devastating epidemic in history.