Investigation of specific antibody titer against SARS-CoV-2 virus during hospitalization and one month after discharge in hospitalized children with severe and critical Covid-19 infection

Background & Aims: The response of the human immune system to the COVID-19 disease is of vital importance in many ways,
including determining the place of serological methods in the survival of patients. Therefore, the present study was designed and
implemented with the aim of determining the specific antibody titer against SARS CoV-2 during hospitalization and one month after
discharge in children hospitalized in Shahid Motahari Hospital in Urmia.
Materials & Methods: In this longitudinal study, hospitalized patients with positive RT-PCR test were included in the study due to
COVID-19. Inclusion criteria included age less than 15 years and parental consent, and exclusion criteria included immune system
disorder or developmental disorder and negative RT-PCR test. Demographic information and severity of the disease along with
specific antibody titer of SARS-CoV-2 were evaluated and extracted for all patients.
Results: The average age of the 40 studied patients was 2.48 years, and 32.5% of them were girls. The average level of IgG during
discharge and one month after discharge was equal to 73.66 and 128.36, respectively, and it was significantly higher one month after
discharge than during discharge (p<0.001). There was no statistically significant difference between the two sexes in terms of
antibody titer during discharge (p=0.77) and one month after discharge (p=0.31). There is no significant relationship between the
specific antibody level of SARS-CoV-2 during discharge (r=0.12 and p=0.45) and one month after discharge and length of
hospitalization. There was no statistically significant difference between disease severity and antibody titer during discharge (p=0.54)
and one month after discharge (p=0.20).
Conclusion: The specific antibody titer of SARS-CoV-2 increases significantly after one month of discharge. There was no
significant difference between the level of this antibody during discharge and one month later between girls and boys and people with
different severity of the disease. No significant relationship between antibody titer and hospitalization time was observed.