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

Naif Khalaf Alharbi; Jaffar A Al-Tawfiq; Amal Alwehaibe; Mohamed W Alenazi; Abdulrahman Almasoud; Abdullah Algaisi; Fahad A Alhumaydhi; Anwar M Hashem; Mohammed Bosaeed; Suliman A Alsagaby

doi:10.2147/IDR.S362848

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

Infect Drug Resist. 2022 Jul 29:15:4127-4136. doi: 10.2147/IDR.S362848. eCollection 2022.

Authors

Naif Khalaf Alharbi^{1

2}, Jaffar A Al-Tawfiq^{3

4

5}, Amal Alwehaibe¹, Mohamed W Alenazi¹, Abdulrahman Almasoud¹, Abdullah Algaisi⁶, Fahad A Alhumaydhi⁷, Anwar M Hashem^{8

9}, Mohammed Bosaeed^{1

2

10}, Suliman A Alsagaby¹¹

Affiliations

¹ Vaccine Development Unit, King Abdullah International Medical Research Center (KAIMRC), Riyadh, Saudi Arabia.
² College of Medicine, King Saud bin Abdulaziz University for Health Science (KSAU-HS), Riyadh, Saudi Arabia.
³ Specialty Internal Medicine and Quality Department, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia.
⁴ Infectious Diseases Division, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
⁵ Infectious Diseases Division, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
⁶ Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia.
⁷ Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia.
⁸ Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
⁹ Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia.
¹⁰ King Abdulaziz Medical City (KAMC), Ministry of National Guard - Health Affairs (MNG-HA), Riyadh, Saudi Arabia.
¹¹ Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Majmaah University, Al Majmaah, Saudi Arabia.

Abstract

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 S1 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: AZD1222; BNT162b2; COVID-19; IgG; Immune responses; antibody; vaccines.

Grants and funding

This study was funded by KAIMRC under the grant RC20/180.