Study shows immune response from H1N1 flu vaccine is short-lived
Health professionals first identified H1N1, or swine flu, in 2009 as the virus rapidly spread and killed countless people around the world. Now, it is one of the flus that spreads every season.
Scientists previously thought that people with the H1N1 flu vaccine had strong immune responses against the virus for approximately 10 years.
The researchers, divided into teams in Australia, China and the U.S., applied a mathematical model to show a map of how the various flu strains spread from 2006 to 2015. The results showed that H1N1 followed a “skip and resurgence” pattern in both Eastern Asia and Europe. For example, the virus was estimated to strike in 2011 and 2012, but there was no outbreak until the next flu season.
The pattern is made clear with fundamental epidemiological theories. When a population has sustained immunity to the virus after the initial infection, the virus cannot outbreak like before, so it spreads elsewhere. When the immunity declines after two years, people become vulnerable to the virus again.