How effective is 13-valent pneumococcal conjugate vaccine (PCV13) combined with 23-valent pneumococcal polysaccharide vaccine (PPSV23)?. Student Medical Journal [Internet]. 2024 Oct. 10 [cited 2024 Oct. 16];2:29-37. Available from: https://journals.ucc.ie/index.php/smj/article/view/4311