Covid-19 infection does not completely protect young people from reinfection, and vaccination is still necessary to boost immune response and reduce disease transmission, according to an observational study published in The Lancet Respiratory Medicine journal.The research was conducted on more than 3,000 healthy members of the US Marines Corps most of whom were aged 18-20 years.The researchers from the Icahn School of Medicine at Mount Sinai in the US emphasised that young people should take up the vaccine wherever possible.They noted that despite previous infection and the presence of antibodies, vaccination is still necessary to boost immune responses, prevent reinfection, reduce transmission."As vaccine roll outs continue to gain.