Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Severe Invasive Disease Caused by Serotype 3 Streptococcus Pneumoniae in Italian Children

• Published in: Vaccines (Basel) Vol. 7; no. 4; p. 128
• Main Authors: Lodi, Lorenzo, Ricci, Silvia, Nieddu, Francesco, Moriondo, Maria, Lippi, Francesca, Canessa, Clementina, Mangone, Giusi, Cortimiglia, Martina, Casini, Arianna, Lucenteforte, Ersilia, Indolfi, Giuseppe, Resti, Massimo, Azzari, Chiara
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24.09.2019; MDPI
• Subjects: Children; Conjugates; Disease control; Immunization; Laboratories; Meningitis; Nosocomial infections; Patients; PCV13; Pediatrics; Pneumonia; Polymerase chain reaction; Population; Sepsis; serotype 3; Serotyping; Streptococcus infections; Streptococcus pneumoniae; Surveillance; vaccination impact; Vaccines; Italy; vaccination impact; PCV13; serotype 3; streptococcus pneumoniae; sepsis
• ISSN: 2076-393X; 2076-393X
• DOI: 10.3390/vaccines7040128

The effectiveness and impact of the 13-valent pneumococcal conjugate vaccine (PCV13) against invasive pneumococcal diseases (IPD) due to serotype 3 (ser3) has been questioned. However, the impact of PCV13 on different clinical presentations of ser3-IPD has not been studied so far. The impact of PCV13 on different clinical presentations of ser3-IPD in a population of Italian children aged 0-8 years was evaluated, comparing pre- and post-PCV13 introduction period. Real-time polymerase chain reaction (PCR) was used for the diagnosis and serotyping of IPD. During the observation period (1 January 2006-1 August 2018), ser3 was detected in 60/284 (21.1%) children under 8 with serotyped IPD. The incidence of sepsis and meningitis was 0.24 per 1,000,000 person-years (p-y) in pre-PCV13 and 0.02 per 1,000,000 p-y in post-PCV13. No cases occurred in vaccinated children. In the post-PCV13 period, case reduction was 13% for all ser3 IPD and 92% for sepsis and meningitis. Vaccination impact may be underestimated due to significant improvement in pneumococcal surveillance in post-PCVC13. Our data suggest a significant impact of PCV13 on meningitis and sepsis due to ser3 and a lower impact against pneumonia. While waiting for increasingly effective anti-pneumococcal vaccines, PCV13, which guarantees protection against the most severe clinical presentations of ser3-IPD, is currently the most effective prevention option available.