Evidence from coronaviruses that cause common colds show the ability to be reinfected but even in that case immunity still lasts for months rather than days. In

Evidence from coronaviruses that cause common colds show the ability to be reinfected but even in that case immunity still lasts for months rather than days. In the case of a more severe disease like SARS, antibody responses have been found after 17 years. We don't know enough about Covid to make a good guess about immunity but it seems unlikely that someone could be reinfected days after recovering.