Longevity of Immunoglobulin-G Antibody Response Against Nucleocapsid Protein Against SARS-CoV-2 Among Healthcare Workers

Abstract

Background

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the latest pandemic and the most significant challenge in public health worldwide. Studying the longevity of naturally developed antibodies is highly important clinically and epidemiologically. This paper assesses the longevity of antibodies developed against nucleocapsid protein amongst our health-care workers.

Methods

This longitudinal cohort study was conducted at a tertiary hospital, Saudi Arabia. Anti-SARSsCoV-2 antibodies were tested among health-care workers at three-point intervals (baseline, eight weeks, and 16 weeks).

Results

Of the 648 participants, 112 (17.2%) tested positive for Coronavirus (COVID-19) by PCR before the study. Of all participants, 87 (13.4%) tested positive for anti-SARS-CoV-2 antibodies, including 17 (2.6%) participants who never tested positive for COVID-19 using rt-PCR. Out of the 87 positive IgG participants at baseline, only 12 (13.7%) had remained positive for anti-SARS-CoV-2 antibodies by the end of the study. The IgG titer showed a significant reduction in values over time, where the median time for the confirmed positive rt-PCR subgroup from infection to the last positive antibody test was 70 (95% CI: 33.4–106.5) days.

Conclusion

Health-care workers are at high risk of exposure to the SARS-CoV-2 virus, and contracting an asymptomatic infection is not unlikely. Developing and sustaining natural immunity differs from one person to another, while the rate of positive IgG anti-SARS-CoV-2 wanes over time.

Clinicaltrials.gov Identifier

NCT04469647, July 14, 2020.

Keywords:

• antibodies
• longevity
• COVID-19
• SARS-CoV-2
• healthcare workers
• HCW

Data Sharing Statement

Datasets including demographical data, serology testing results and questionnaire responses can be provided upon request from Dr. Hayat Mushcab. The encrypted dataset can be uploaded to the system and shared with the reviewers accordingly.

Ethics

The study adheres to the Declaration of Helsinki and has received the Institutional Review Board’s approval (IRB # 20-09) on the 13th of May 2020.

Informed Consent

Each participant was assigned a study ID, written informed consent, and a hard copy of the WHO’s risk factors assessment questionnaire.

Acknowledgment

The authors of this study would like to thank JHAH’s management and staff for their full support and volunteering for completing the study. The authors would also like to thank Ms. Suha Amoudi and Mr. Nizar Aridi for their support and facilitating the laboratory testing for all the participants and Mr. Issam Abduljabar and Mr. Salam Abu Ghaida for their efforts in data entry.

Author Contributions

All authors contributed significantly to work reported, whether in the conception, study design, execution, acquisition of data, analysis, and interpretation, or in all these areas. They took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; agreed on the journal to which the article has been submitted; and agreed to be accountable for all aspects of the work.

Disclosure

All authors declare that there is no competing financial interest directly or indirectly in this work.

Additional information

Funding

The study has received internal funds from the allocated institution’s budget for the COVID-19 task force.