H3N2 influenza virus particles, TEM - stock photo

H3N2 influenza virus particles, coloured transmission electron micrograph (TEM). Each virus consists of a nucleocapsid (protein coat) that surrounds a core of RNA (ribonucleic acid) genetic material. Surrounding the nucleocapsid is a lipid envelope that contains the glycoprotein spikes haemagglutinin (H) and neuraminidase (N). These viruses were part of the Hong Kong Flu pandemic of 1968-1969 that killed approximately one million worldwide. H3N2 viruses are able to infect birds and mammals as well as humans. They often cause more severe infections in the young and elderly than other flu strains and can lead to increases in hospitalisations and deaths.