This study assessed the long-term persistence of the cellular (CD8+ T-cell) and humoral response six months after SARS-CoV-2 vaccine booster. Samples were collected from vaccinated (CoronaVac or ChAdOx1) healthcare professionals (n=25) 6 months after the 1st booster (BNT162b2) and up to 3 months after the 2nd booster (BNT162b2 or Ad26.COV2. S) (n=18). IFN-gproducing T-cells in response to mega peptides pools of spike protein (S-MP) from the original sequence and the gamma, delta, omicron, omicron BA.4-5, and omicron XBB.1 variants was quantified using ELISPOT and expressed as spot-forming cells (SFC)/106 cells. Percent inhibition (PI) of neutralizing antibodies (nAbs) was quantified using the ECOF COVID nAb kit. To date, nine participants with 1st boosters (CoronaVac+BNT162b2, n=6, and ChAdOx1+BNT162b2, n=3) and thirteen participants with 2nd boosters were evaluated by ELISPOT. The frequency of responders to S-MP was 33% in the CoronaVac+BNT162b2 group and 67% in the ChAdOx1+BNT162b2 group. The CoronaVac+BNT162b2 responded more for gamma (50%), delta (50%), omicron (50%), omicron BA.4-5 (67%), and XBB.1 (83%) variants. In the ChAdOx1+BNT162b2 group, all participants responded to Omicron XBB.1, and the frequency of responders to other variants was similar (67%). The mean SFC in response to MP of the original sequence was higher in the ChAdOx1+BNT162b2 (415.8 SFC/106 cells, SD 591.1) than in the CoronaVac+BNT162b2 group (294.2 SFC/106 cells, SD 470.5). Mean SFC between groups in response to variants was similar. There was no significant increase in SFC after the 2nd booster. The PI of nAb after the 1st booster was higher in the CoronaVac+BNT162b2 (90%, SD 24) than in the ChAdOx1+BNT162b2 group (71%, SD 27). PI increased after the 2nd booster (83%, SD 27 to 99%, SD 2; p<0.05). In conclusion, cellular and nAb responses persisted 6 months after vaccination, regardless of the primary vaccination schedule. The 2nd booster enhanced the PI, but not the cellular response.