Immunity to reinfection from human coronaviruses may last only lasts six months, according to a study from the University of Amsterdam.
It casts doubt over the practicality of introducing "immunity passports", which some governments want to issue to COVID-19 survivors on the assumption they can't be reinfected and are free to help the economy get back on its feet.
The study monitored 10 men over 35 years to determine antibody levels following infection for any of the four seasonal human