Seasonal influenza is a highly contagious, acute respiratory illness that affects people of all ages. The major pathogens, influenza A viruses, are classified into serologically defined antigenic subtypes of the hemag...Seasonal influenza is a highly contagious, acute respiratory illness that affects people of all ages. The major pathogens, influenza A viruses, are classified into serologically defined antigenic subtypes of the hemagglutinin （HA） and neuraminidase （NA）. Of 16 identified HA and 9 NA subtypes, only H1N1 and H3N2 subtypes are now circulating among humans. Influenza vaccines have been available for over 60 years and well proven to be an effective public health intervention to control seasonal influenza epidemics. Seasonal influenza vaccines presently available, inactivated or split, contain the circulating strains of influenza A virus H3N2, H1N1 and influenza B virus. The composition of the vaccine is renewed semi-annually, as necessary, based on surveillance data.展开更多
文摘Seasonal influenza is a highly contagious, acute respiratory illness that affects people of all ages. The major pathogens, influenza A viruses, are classified into serologically defined antigenic subtypes of the hemagglutinin （HA） and neuraminidase （NA）. Of 16 identified HA and 9 NA subtypes, only H1N1 and H3N2 subtypes are now circulating among humans. Influenza vaccines have been available for over 60 years and well proven to be an effective public health intervention to control seasonal influenza epidemics. Seasonal influenza vaccines presently available, inactivated or split, contain the circulating strains of influenza A virus H3N2, H1N1 and influenza B virus. The composition of the vaccine is renewed semi-annually, as necessary, based on surveillance data.
