Antibody Response to ChAdOx1-nCoV-19 Vaccine Among Recipients in Bangladesh: A Prospective Observational Study

Abstract

Purpose

The aim of the study was to assess the antibody response to the ChAdOx1-nCoV vaccine in individuals who were not previously infected by COVID-19.

Patients and Methods

All people aged 18–65 years who received their first vaccination with ChAdOx1-nCoV from March to May 2021 were approached for inclusion. Individuals with sufficient antibody titers against SARS-CoV-2 infection before vaccination were considered previously infected and were excluded from the analysis. We observed viral spike protein RBD-S1-specific IgG antibody levels at day 28 of the first dose of vaccination and day 14 of the second dose of vaccination (74 days from index vaccination). An optical density ratio (ODR) of >1.1 was considered to have a positive antibody response, 0.8 to 1.1 borderline and <0.8 was denoted as negative. Informed consent was ensured before enrollment, and ethical principles conformed with the current Declaration of Helsinki.

Results

This observational study comprised 769 infection-naïve individuals (mean age 40.5 years, 38.9% female). Spike-specific IgG antibody responses elicited after the first and second doses of vaccine were 99.9% and 100%, respectively. The median ODR was 5.43 (interquartile range [IQR]: 4.32–6.98) and 10.90 (IQR 9.02–11.90) after the first and second doses. Higher age was associated with lower antibody levels after both dosages. However, no sex-specific variation was seen. People with comorbidity had a lower antibody level after the second dose. Tenderness (51.46%) and fever (19.30%) were the most common local and systemic side effects after vaccination.

Conclusion

This study was one of the earlier attempts in the country to assess the antibody response to ChAdOx1-nCoV vaccine recipients. The results imply that general people should be encouraged to take the vaccine at their earliest.

Keywords:

• ChAdOx1-nCoV
• vaccine
• COVID-19
• Bangladesh
• antibody response

Acknowledgments

The author thanks the respondents who participated in the study during this stressful situation. The authors are also thankful to the research team of the ‘Pi Research Consultancy Center’ (www.pircc.org) for support throughout the study period, especially for journal selection and manuscript formatting.

Abbreviations

COVID-19, Coronavirus disease 2019; ODR, Optical density ratio; RBD, Receptor binding domain; RT-PCR, Reverse transcriptase polymerase chain reaction.

Data

Available on request.

Ethical Consideration

Ethical measures were taken throughout the study period to maintain a high standard of confidentiality and anonymity of the participants. Formal ethical clearance was taken from the Ethical Review Committee of Sheikh Hasina National Institute of Burn & Plastic Surgery (No- SHNIBPS/Feb (20)/05). Informed written consent was taken from the participants before inclusion.

Consent of Publication

All authors agreed to publish the article.

Author Contributions

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

Disclosure

The authors declare that there are no conflicts of interest in this work.