Epidemiological Changes in Serum Virus-Specific IgM/IgG Antibody in SARS-CoV-2 Patients in Guilan Province: A Comparative Study

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the respiratory disease coronavirus disease 2019 (COVID-19) pandemic. To identify those who have been exposed to the virus and maybe to forecast disease immunity, antibody tests are crucial. We aimed to examine the association between prior COVID-19 infection and antibody levels, including immunoglobulin M (IgM) and immunoglobulin G (IgG) while considering the underlying illnesses in COVID-19 patients in Guilan province.

In this descriptive study, 212 individuals with a COVID-19 history participated. Blood samples were taken from people twice. The first time of blood sample collection was in April 2020. The second blood sample collection was around three months after the first time in August 2020. The total immunoglobulins levels specific to SARS-CoV-2 were measured using quantitative enzyme-linked immunosorbent assay (ELISA).

The study included 212 participants, 101 (47.6%) were males, and 111 (52.4%) were women. The age of those who recovered most commonly ranged from 31 to 45 years (31.1%). The most common underlying diseases were Hypertension (31/212), obesity (23/212), cardiovascular disease (17/212), diabetes (17/212), and chronic obstructive pulmonary disease (COPD), respectively. The findings showed that, three months after recovery, the level of IgG remained persistent while the level of IgM had decreased. This revealed that 26/212, or 12.26%, had IgG levels above 1.1.

In individuals who had previously contracted COVID-19, the level of IgG increased over time, whereas the level of IgM decreased.