目的 To evaluate effectiveness of 23-valent pneumococcal polysaccharide vaccine(PPSV23)inoculated between one and two years post cancer diagnosis in elderly colorectal cancer patients on pneumonia hospi
目的 To evaluate effectiveness of 23-valent pneumococcal polysaccharide vaccine(PPSV23)inoculated during one year after cancer diagnosis in colorectal cancer patients on pneumonia hospitalization incide