Even 9 months after infection with the SARS-CoV-2 coronavirus, a sufficient amount of antibodies remains in the human body, regardless of whether the infection was overt or asymptomatic, said researches from the University of Padua and Imperial College London.
According to MedicalXpress, the authors of the study tested more than 85% of residents in the Italian commune of Vaud for coronavirus infection in February and March 2020. Antibody retests were performed in May and November 2020. It turned out that in 98.8% of people infected in February or March, antibody levels remained high until November. What's more, there was no difference in antibody levels between people who had symptoms of COVID-19 and those who had no symptoms.
The level of protection against coronavirus was monitored using three tests that detect different types of antibodies that respond to different parts of the virus. The results showed that levels of all types of antibodies decreased between May and November, but the rate of decline was different depending on the test. Some people have had an increase in antibody levels, which may indicate reinfection, which strengthens the immune system. Thus, the strength of the immune response was independent of the symptoms and severity of the infection.