Persistence of Anti-SARS-CoV-2 Spike IgG Antibodies Following COVID-19 Vaccines

• Published in: Infection and drug resistance Vol. 15; pp. 4127 - 4136
• Main Authors: Alharbi, Naif Khalaf, Al-Tawfiq, Jaffar A, Alwehaibe, Amal, Alenazi, Mohamed W, Almasoud, Abdulrahman, Algaisi, Abdullah, Alhumaydhi, Fahad A, Hashem, Anwar M, Bosaeed, Mohammed, Alsagaby, Suliman A
• Format: Journal Article
• Language: English
• Published: Macclesfield Dove Medical Press Limited 01.01.2022; Taylor & Francis Ltd; Dove; Dove Medical Press
• Subjects: Antibodies; antibody; azd1222; bnt162b2; Coronaviruses; covid-19; COVID-19 vaccines; Disease transmission; Enzyme-linked immunosorbent assay; FDA approval; Health aspects; igg; Immune response; immune responses; Immunoglobulin G; Infections; Original Research; Pandemics; Pharmaceutical industry; Severe acute respiratory syndrome coronavirus 2; Software; Statistical analysis; Vaccination; Vaccines; Saudi Arabia; United States; United Kingdom
• ISSN: 1178-6973; 1178-6973
• DOI: 10.2147/IDR.S362848

Purpose: This study was conducted to investigate antibody immune responses induced by BNT162b2 and AZD1222 human COVID- 19 vaccines in Riyadh city, Saudi Arabia. Patients and Methods: ELISA was used to evaluate antibodies, against the SARS-CoV-2 spike SI protein, in serum samples from 432 vaccinated individuals at six time points: pre-vaccination (baseline), post-prime, post-boost, 6-months, and 1 year post-vaccination, and 3 weeks post a third dose. Virus microneutralization assay was used to confirm antibody responses in a subset of samples. Results: Anti-SARS-CoV-2 spike IgG were detected in most subjects post-prime, reached a peak level post-boost, and remained at high level at the 6-month follow-up. At 1 year post-vaccine, the antibody levels were low but increased to a significant level higher than the peak following a third dose. The third dose was given at an average of 250 days after the second dose. The virus microneutralization assay confirmed the neutralization activity of the induced SARS-CoV-2 IgG antibodies. The vaccines induced higher IgG titres at post-prime (p=0.0001) and 6 months (p=0.006) in previously infected individuals. An increased interval between prime and boost, more than recommended time, appeared to enhance the IgG levels (p=0004). Moreover, the vaccines induced higher IgG levels in younger subjects (p=0.01). Conclusion: These data provide insights and build on the current understanding of immune responses induced by these two vaccines; and support a third boosting dose for these COVID-19 vaccines. Keywords: COVID-19, vaccines, BNT162b2, AZD1222, Immune responses, antibody, IgG