Thus, while some studies show consistent antibody responses regardless of CD4+ T lymphocyte counts at the time of vaccination, other studies suggest stronger antibody responses in PLWH with CD4+ T lymphocyte counts above 200 cells/μL or 500 cells/μL at the time of vaccination with the 23-valent pneumococcal polysaccharide vaccine, and above 350 cells/μL at the time of vaccination with the inactivated, quadrivalent influenza vaccine [13,19]. Here, CD4 is linked to influenza.