A 6-year-old boy with no significant past medical history presents to the emergency department with a 3-day history of fever (39.5°C), productive cough, and right-sided pleuritic chest pain. Vital signs are: HR 118/min, RR 30/min, BP 108/70 mmHg, SpO2 93% on room air. Physical examination reveals diminished breath sounds and crackles in the right lower lobe. Chest radiograph shows right lower lobe consolidation with a small pleural effusion. Sputum culture grows alpha-hemolytic, optochin-sensitive streptococci. The patient has completed the primary pneumococcal vaccination series (PCV13 at 2, 4, 6, and 12-15 months of age). Which of the following best explains how pneumococcal conjugate vaccine (PCV13) prevents invasive pneumococcal infection in vaccinated individuals?

1. A)The vaccine contains live attenuated pneumococcal strains that outcompete pathogenic strains in the nasopharynx
2. B)The vaccine provides 100% protection against all serotypes of Streptococcus pneumoniae
3. C)The vaccine induces opsonizing antibodies against pneumococcal capsular polysaccharides, enhancing complement-mediated bacteriolysis and phagocytosisGABARITO
4. D)The vaccine prevents bacterial colonization by neutralizing pneumococcal virulence factors in respiratory secretions
5. E)The vaccine cross-reacts with cell wall proteins found on all gram-positive bacteria, providing broad protection