Longitudinal changes in IgG levels among COVID-19 recovered patients: A prospective cohort study

  • Ashraf Hassan Alzaabi
  • , Luai A. Ahmed
  • , Abdulla E. Rabooy
  • , Ali Al Zaabi
  • , Mohammed Alkaabi
  • , Falah AlMahmoud
  • , Mai Farouk Hamed
  • , Khalid Omar Bashaeb
  • , Abdul Rahim Bakhsh
  • , Suha Adil
  • , Nadeen Elmajed
  • , Ahmed Nigm Abousalha
  • , Ahmad Kanaan Uwaydah
  • , Khulood Al Mazrouei

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Objectives To quantify SARS-CoV2 IgG antibody titers over time and assess the longevity of the immune response in a multi-ethnic population setting. Setting This prospective study was conducted in a tertiary hospital in Abu Dhabi city, UAE, among COVID-19 confirmed patients. The virus-specific IgG were measured quantitatively in serum samples from the patients during three visits over a period of 6 months. Serum IgG levels 15 AU/ml was used to define a positive response. Participants 113 patients were analyzed at first visit, with a mean (SD) age of participants of 45.9 (11.8) years 87.5% of the patients were men. 63 and 27 participants had data available for visits 2 and 3, respectively. Primary outcome Change in SARS-CoV2 IgG antibody titers over the visits. Results No mortality or re-infection were reported. 69% of the patients developed positive IgG response within the first month after the onset of symptoms. The levels of IgG showed a consistent increase during the first three months with a peak level during the third month. Increasing trend in the levels of IgG were observed in 82.5%, 55.6% and 70.4% of patients between visit 1 to visit 2, visit 2 to visit 3, and from visit 1 to visit 3, respectively. Furthermore, about 64.3% of the patients showed sustained increase in IgG response for more than 120 days. Conclusions Our study indicates a sustained and prolonged positive immune response in COVID-19 recovered patients. The consistent rise in antibody and positive levels of IgG titers within the first 5 months suggest that immunization is possible, and the chances of reinfection minimal.

Original languageEnglish
Article numbere0251159
JournalPLoS ONE
Volume16
Issue number6 June 2021
DOIs
Publication statusPublished - Jun 2021

ASJC Scopus subject areas

  • General

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