The flu community has always had a concept known as “antigenic imprinting” – that is, initial exposure, and the resulting age-related susceptibility to different subtypes of influenza. In other words, the type of flu a person who has been exposed to at a young age has an effect on the immune system’s antiviral response over the next period of time. A new study from McMaster University provides more evidence for this claim.
(Source: McMaster University, via New Atlas)
Using rare flu season data, the researchers found rapid changes in infection trends associated with the patient’s age.
Most of the two subtype influenza viruses that cause coughing, pain and fever usually have a seasonal cycle.
However, the flu season of 2018/2019 is somewhat unusual. Because h1N1 and H3N2 are two subtypes, they dominate at different times of the season.
Flu researchers at McMaster University say this is a rare opportunity to delve into antigen imprints.
The scientists collected data for this unusual 2018/2019 flu season and studied the relationship between a person’s age and their susceptibility to H1N1/H3N2 influenza.
(From: Clinical Diseases)
“From previous studies, susceptibility to a particular influenza subtype has been known to be related to the year a person was born,” said Alain Gagnon of the University of Montreal, a researcher.
This new study goes a step further in supporting antigen imprinting, as we have not only found ways in which it is associated with a specific age in a single flu season, but also with one (or another) subtype.
In addition, we used a unique ‘natural experiment’ to show how changes in the advantages of a season’s Central Asian type are actually triggered by age.
During a flu season, this susceptibility changes immediately, which seems to be determined by age.
For public health officials who need to prepare for an epidemic, we can help them determine which part of the age group in the statistics is at the highest risk and depends on the valuable evidence of the subtype being transmitted.
Study co-author Matthew Miller said: “Previously, there was some doubt about the immunity of viruses such as influenza (and even coronaviruses) and their potentially significant pathogenic effects in subsequent epidemics and pandemics.”
Understanding how previous immunization experiences protect people, or cause them to become susceptible, is important in helping us identify the significant risks to specific populations during seasonal epidemics and new outbreaks.
Details of the study have been published in the recently published journal Clinical Infectious Diseases. Originally published as:
Age-specific ge of influenza A responds to change in virus subtype dominance