Does the COVID-19 seroconversion in older adults resemble the young?

Abstract

High antibody titers have been found to correlate with the severity of coronavirus disease 2019 (COVID-19) disease. Therefore, antibody titers may be higher in older adults, whose disease is known to have a more severe course than younger ones. This study aimed to compare the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin G (IgG) antibody level in the reverse transcription-polymerase chain reaction (RT-PCR) to test positive older adults with young. Patients aged ≥18 with positive RT-PCR and checked serum IgG antibodies between November 1, 2020 and January 13, 2021 were included. The IgG antibody levels and the time between RT-PCR positivity with the antibody levels were recorded. A total of 1071 patients were divided into two groups as Group 1 <60 years old (n = 902) and Group 2 ≥60 years old (n = 169). The SARS-CoV-2 IgG antibody titers were higher in Group 2 (p = 0.001). This height was present in the first 3 months after positive RT-PCR. While the antibody titers were compared by dividing Group 2 into the three groups according to age ranges (60-69, 70-79, and ≥80 years), the antibody titer was higher in ≥80 years patients (p = 0.044). High COVID-19 IgG antibody levels may be associated with the severity of the disease. Also, the humoral immunity advantage was seen in the first 3 months in the older patients, which suggests that older adults with COVID-19 may develop reinfection in the long term.

Keywords: COVID-19; SARS-CoV-2; antibody; older adults; seroconversion.

Figure 1

The titers of IgG antibody to SARS‐CoV‐2 in the young and older patients. IgG, immunoglobulin G; SARS‐CoV‐2, severe acute respiratory syndrome coronavirus 2

Figure 2

The relationship between the age and IgG antibody titers to SARS‐CoV‐2. IgG, immunoglobulin G; SARS‐CoV‐2, severe acute respiratory syndrome coronavirus 2