Background: Both COVID-19 vaccination and acute infection result in cellular and humoral immune responses with variant degrees of protection. Most studies address the difference in humoral response (antibody levels) between these two groups, while evaluations of the cellular response are scarce. 

Aims: To evaluate the differences in immune responses between patients that were vaccinated or recovered from COVID-19 and their correlations.

Methods: Prospective study in a large medical center. The vaccinated group included health care workers 30 days after the second dose of the BNT162b2 vaccine. The recovered group included adults 3-6 weeks after proven COVID-19 infection. Serum anti-spike IgG and cytokine levels were taken at inclusion. Multivariate linear regression models with age, sex, BMI, and smoking status were used to assess differences in cytokines.

Results: 39 participants were included in each group. The mean age was 53 ±14 and 53% were males. Baseline characteristics were similar between the groups. Serum levels of IL-6 (?=-0.4, p<0.01), TNF? (?=-0.3, p=0.02), IL-8 (?=-0.4, p<0.01), CCL2 (?=-0.4, p<0.01), VCAM-1 (?=-0.3, p<0.02), and MMP-7 (?=-0.6, p<0.01) were higher in the recovered group compared to the vaccinated group using the multivariate analyses. Serum anti-spike levels were lower among the recovered group than the vaccinated (124 vs. 208 pg/ml, p<0.001). We did not find any correlations between antibody levels and the cytokines mentioned above.

Conclusions: Recovered COVID-19 patients had higher cytokines levels but lower antibodies than vaccinated participants. Cytokines might be of higher value as markers for immunity against COVID-19 infection.