A study measures COVID neutralizing antibody levels in COVID patients who experienced mild, severe, and asymptomatic disease, finding that 99% of patients maintained significant levels of antibodies 200 days after infection.
People with severe disease had higher levels of antibodies than those with mild or asymptomatic disease.
The researchers note that even after antibody levels drop, re-exposure to the virus may prompt the immune system to create more antibodies. Even though antibodies might not prevent re-infection completely, they can decrease the severity of subsequent infections.