Duration of antibody responses following severe acute respiratory syndrome coronavirus 2 infection.

BACKGROUND

Little is known on the duration of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) antibodies in patients following SARS-CoV-2 infection.

AIMS

We aimed to determine the duration of the immunoglobulin G (IgG) and M (IgM) antibody responses following SARS-CoV-2 infection and to evaluate the risk factors for a short duration of anti-SARS-CoV-2 IgG.

METHODS

We measured antibody responses in 94 patients who had recovered from SARS-CoV-2 infection. The chi-square test and multivariable logistic regression analysis were used to identify risk factors for a short duration (< 6 months) of anti-SARS-CoV-2 IgG.

RESULTS

IgG antibodies were detectable in all patients until 4 months; 19 (21.8%) convalescent patients reverted to IgG negative 4-6 months after symptom onset. IgM antibodies decreased significantly to 5.7% at 4-6 months after symptom onset. Patient characteristics were not associated with a short duration of detectable IgG.

CONCLUSIONS

A substantial fraction of convalescents may exhibit a transient IgG response following SARS-CoV-2 infection. Our findings suggest that patients who have recovered from SARS-CoV-2 infection should also be vaccinated if their anti-SARS-CoV-2 IgG antibodies are undetectable.