In addition, the results showed that booster vaccination appeared to further reduce the risk of COVID-19-related infections, hospitalizations, and deaths compared with the primary vaccination.<h4>Conclusion</h4>It was shown that booster vaccination with the COVID-19 vaccine provided a high IRR in PLWH and still produced a desirable moderate IRR in PLWH with a CD4<sup>+</sup> T-cell count of ≤ 200. This evidence concerns the gene CD4 and COVID-19.