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Context Vaccination against Sars-Cov-2 is in full swing during COVID-19 pandemic. One of the efficient methods to evaluate response to vaccination is the assessment of humoral immunity by measuring Sars-Cov-2 antibody titer. Identification of factors that affect the humoral response is important so as to ameliorate the responses to vaccination or identify vulnerable groups that may need vaccination boosters. Objective We investigated the effect of anthropometric parameters (age, BMI), smoking, diabetes, statin use hypertension and levels of 25(OH)D and DHEAS to the Sars-Cov-2 antibody titer. Methods In this longitudinal observational cohort study 712 subjects were tested for Sars-Cov-2 antibodies 3 months after the second dose of BNT162b2 vaccine. Multiple linear regression analysis was performed to identify which factors are associated with the antibody titer. Results We identified age to be negatively associated with antibody titer (p=0.0073) and male sex (p=0.0008). However, interaction of age and gender was significant (p<0.0001) highlighting the finding that only after the age of 40 years men had lower antibody levels than women. DHEAS, an aging marker, was not associated with the antibody titer. Smoking was also associated with low antibody titer (p=0.0008) while overweight or obese subjects did not have different antibody response compared to normal weight individuals. Although diabetic and hypertensive subjects trended towards lower antibody titer, this association was not statistically significant. Replete vitamin D levels were associated with higher antibody titers (p=0.00422). Conclusions Age, male sex and smoking negatively affects antibody titer while 25(OH)D is associated with increased Sars-Cov-2 antibody titers.

Competing Interest Statement

The authors have declared no competing interest.

Clinical Trial


Funding Statement

No external funding was received

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.


The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study was approved by the University Hospital of Patras Ethics Committee, approval ID 99-25/2/202

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.


I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).


I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.


Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv

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