BibTex format
@article{Liatsikos:2026:10.1016/j.lanmic.2025.101267,
author = {Liatsikos, K and Hyder-Wright, A and Davies, K and El, Safadi D and Farrar, M and Goncalves, A and Gonzalez-Dias, P and Gordon, SB and Howard, A and Lesosky, M and Liu, X and Mitsi, E and Myerscough, C and Nyazika, TK and Pollard, AJ and Reiné, J and Robinson, RE and Solórzano, C and Urban, BC and Zhang, Y and Lahuerta, M and Theilacker, C and Catusse, J and Begier, E and Tan, Y and Jodar, L and Gessner, BD and Collins, A and Ferreira, DM and PNEUMO, 2 study group},
doi = {10.1016/j.lanmic.2025.101267},
journal = {Lancet Microbe},
title = {The effect of pneumococcal conjugate vaccine and pneumococcal polysaccharide vaccine on nasopharyngeal colonisation following human infection challenge with serotype 3 and serotype 6B (PREVENTING PNEUMO 2): a double-masked, randomised, controlled, phase 4 trial.},
url = {http://dx.doi.org/10.1016/j.lanmic.2025.101267},
year = {2026}
}
RIS format (EndNote, RefMan)
TY - JOUR
AB - BACKGROUND: Although evidence suggests some direct protection from the 13-valent pneumococcal conjugate vaccine (PCV13) against Streptococcus pneumoniae serotype 3 (Spn3), Spn3 remains a frequent cause of pneumococcal disease in the UK, potentially due to lower vaccine effect on colonisation, shorter duration of protection, or the emergence of more successful Spn3 clades. To test these hypotheses, we compared PCV13 and 23-valent pneumococcal polysaccharide vaccine (PPV23) protection against prevalent Spn3 clades. Additionally, we assessed the long-term protection offered by pneumococcal vaccines against colonisation using S pneumoniae serotype 6B (Spn6B), a serotype PCV13 protects against in the short term. METHODS: This double-masked, randomised, controlled, phase 4 trial recruited healthy participants aged 18-50 years in Liverpool, UK, and assigned them (2:1:2) to PCV13, PPV23, or placebo (0·9% NaCl). Participants assigned to the PPV23 group were challenged with clade Iα, and participants in PCV13 and placebo groups were subsequently randomly assigned to receive clade Iα or II Spn3. Nasal challenge with Spn3 was at 1 month and with Spn6B in a subgroup at 6 months after vaccination. Selection for this subgroup was conducted on a first-come-first-served basis, with participants who enrolled earliest being offered participation in both challenges. Recruitment for the second challenge was discontinued once the target number of participants was reached. The primary outcome was the acquisition risk of the challenge strain as detected by nasal wash culture at 2 days, 7 days, 14 days, or 23 days in the vaccine versus the placebo groups. The analysis was performed in a modified intention-to-treat population, defined as all participants who received vaccination, underwent challenge, and had at least one nasal wash sample collected after the challenge. Randomisation used a computer-generated schedule that only the unmasked team could access. The unmasked t
AU - Liatsikos,K
AU - Hyder-Wright,A
AU - Davies,K
AU - El,Safadi D
AU - Farrar,M
AU - Goncalves,A
AU - Gonzalez-Dias,P
AU - Gordon,SB
AU - Howard,A
AU - Lesosky,M
AU - Liu,X
AU - Mitsi,E
AU - Myerscough,C
AU - Nyazika,TK
AU - Pollard,AJ
AU - Reiné,J
AU - Robinson,RE
AU - Solórzano,C
AU - Urban,BC
AU - Zhang,Y
AU - Lahuerta,M
AU - Theilacker,C
AU - Catusse,J
AU - Begier,E
AU - Tan,Y
AU - Jodar,L
AU - Gessner,BD
AU - Collins,A
AU - Ferreira,DM
AU - PNEUMO,2 study group
DO - 10.1016/j.lanmic.2025.101267
PY - 2026///
TI - The effect of pneumococcal conjugate vaccine and pneumococcal polysaccharide vaccine on nasopharyngeal colonisation following human infection challenge with serotype 3 and serotype 6B (PREVENTING PNEUMO 2): a double-masked, randomised, controlled, phase 4 trial.
T2 - Lancet Microbe
UR - http://dx.doi.org/10.1016/j.lanmic.2025.101267
UR - https://www.ncbi.nlm.nih.gov/pubmed/41698388
ER -
