"Heterosubtypic immunity (HSI) is defined as cross-protection to infection with an

influenza A virus ''Influenza A virus'' (''IAV'') causes influenza in birds and some mammals, and is the only species of the genus ''Alphainfluenzavirus'' of the virus family ''Orthomyxoviridae''. Strain (biology)#Microbiology or virology, Strains of all subtypes ...

serotype A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their surface antigens, allowing the epi ...

other than the one used for primary infection." In

layman's terms Plain English (or layman's terms) are groups of words that are to be clear and easy to know. It usually avoids the use of rare words and uncommon euphemisms to explain the subject. Plain English wording is intended to be suitable for almost anyone, ...

: an 'infection with "seasonal" influenza A viruses could induce

immunity Immunity may refer to: Medicine * Immunity (medical), resistance of an organism to infection or disease * ''Immunity'' (journal), a scientific journal published by Cell Press Biology * Immune system Engineering * Radiofrequence immunity desc ...

against unrelated sub-strains.'

Leicester Mercury The ''Leicester Mercury'' is a British regional newspaper for the city of Leicester and the neighbouring counties of Leicestershire and Rutland. The paper began in the 19th century as the ''Leicester Daily Mercury'' and later changed to its pre ...

''Winter flu could help protect kids'', 30 October 2009

References

{{DEFAULTSORT:Influenza A Virus Immunology Influenza vaccines Influenza A virus