After having COVID-19, reinfection is possible, but the protection from the initial infection usually lasts several months. Reinfections can occur as early as a few weeks after a previous infection, although this is rare. Most commonly, immunity lasts about six months or more, but wanes gradually over time, especially with the emergence of new variants like Omicron and its subvariants. Reinfections tend to occur more frequently when antibody levels decline and the virus mutates, and while reinfections are often milder, severe illness can still occur, especially in older adults or those with weakened immune systems. Vaccination after infection can prolong immunity and reduce the risk of severe disease upon reinfection. The CDC notes that reinfection can happen within weeks but is uncommon so soon after initial recovery.
In summary, one can get COVID-19 again generally after a few months from the first infection, but in rare cases, reinfection can happen within weeks, depending on immunity status and virus variants circulating.
