Claire von Mollendorf1, Eileen M Dunne2, Sophie La Vincente3, Mukhchuluun Ulziibayar4, Bujinlkham Suuri4, Dashtseren Luvsantseren4, Dorj Narangerel5, Belinda D Ortika3, Casey L Pell3, Monica L Nation3, Ahmed Alamrousi3, Jason Hinds6, Sodbayar Demberelsuren7, Cattram Nguyen2, Tuya Mungun4, E Kim Mulholland8, Catherine Satzke9. 1. New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Australia. Electronic address: claire.vonmollendorf@mcri.edu.au. 2. New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Australia. 3. New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia. 4. National Center of Communicable Diseases (NCCD), Ministry of Health, Ulaanbaatar, Mongolia. 5. Ministry of Health, Ulaanbaatar, Mongolia. 6. Institute for Infection and Immunity, St George's, University of London, London, UK; BUGS Bioscience, London Bioscience Innovation Centre, London, UK. 7. Expanded Programme on Immunization, World Health Organization, Ulaanbaatar, Mongolia. 8. New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Australia; Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK. 9. New Vaccines, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Australia; Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, Australia.
Abstract
BACKGROUND: Nasopharyngeal carriage of Streptococcus pneumoniae precedes disease, is the source of pneumococcal community spread, and the mechanism for herd protection provided by pneumococcal conjugate vaccines (PCVs). There are few PCV impact studies in low- and middle-income countries, particularly in Asia. In 2016, Mongolia introduced the 13-valent PCV (PCV13) in a phased manner using a 2 + 1 schedule, with catch-up. We aimed to assess the impact of PCV13 introduction on nasopharyngeal pneumococcal carriage and density in children in Mongolia. METHODS: We conducted two cross-sectional carriage surveys (pre- and one year post-PCV) at community health clinics in two districts of the capital city, Ulaanbaatar in both May-July 2015 and 2017. The study analysis included 961 children too young to be vaccinated (5-8 weeks old) and 989 children eligible for vaccination (12-23 months old). Pneumococci were detected by quantitative real-time PCR and molecular serotyping performed using DNA microarray. FINDINGS: One year post-PCV introduction, PCV13 serotype carriage reduced by 52% in 12-23 month olds (adjusted prevalence ratio [aPR] 0.48 [95% confidence interval [CI] 0.39-0.59]), with evidence of non-PCV13 serotype replacement (aPR 1.55 [95% CI 1.30-1.85]), compared with the pre-PCV period. In 5-8 week olds, PCV13 serotype carriage reduced by 51% (aPR 0.49 [95% CI 0.33-0.73]) with no significant change in non-PCV13 serotype carriage (aPR 1.10 [95% CI 0.83-1.46]). An increase was observed in both PCV13 and non-PCV13 pneumococcal density post-PCV introduction. Antimicrobial resistance (AMR) genes were common, with 82.3% of samples containing at least one of the 10 AMR genes assessed. CONCLUSION: This study demonstrates substantive PCV13 impact on pneumococcal carriage one year post-vaccine introduction in Mongolia. The reductions in PCV13 serotype carriage are likely to result in reductions in pneumococcal disease including indirect effects. Increases in non-PCV13 serotypes require further monitoring.
BACKGROUND: Nasopharyngeal carriage of Streptococcus pneumoniae precedes disease, is the source of pneumococcal community spread, and the mechanism for herd protection provided by pneumococcal conjugate vaccines (PCVs). There are few PCV impact studies in low- and middle-income countries, particularly in Asia. In 2016, Mongolia introduced the 13-valent PCV (PCV13) in a phased manner using a 2 + 1 schedule, with catch-up. We aimed to assess the impact of PCV13 introduction on nasopharyngeal pneumococcal carriage and density in children in Mongolia. METHODS: We conducted two cross-sectional carriage surveys (pre- and one year post-PCV) at community health clinics in two districts of the capital city, Ulaanbaatar in both May-July 2015 and 2017. The study analysis included 961 children too young to be vaccinated (5-8 weeks old) and 989 children eligible for vaccination (12-23 months old). Pneumococci were detected by quantitative real-time PCR and molecular serotyping performed using DNA microarray. FINDINGS: One year post-PCV introduction, PCV13 serotype carriage reduced by 52% in 12-23 month olds (adjusted prevalence ratio [aPR] 0.48 [95% confidence interval [CI] 0.39-0.59]), with evidence of non-PCV13 serotype replacement (aPR 1.55 [95% CI 1.30-1.85]), compared with the pre-PCV period. In 5-8 week olds, PCV13 serotype carriage reduced by 51% (aPR 0.49 [95% CI 0.33-0.73]) with no significant change in non-PCV13 serotype carriage (aPR 1.10 [95% CI 0.83-1.46]). An increase was observed in both PCV13 and non-PCV13 pneumococcal density post-PCV introduction. Antimicrobial resistance (AMR) genes were common, with 82.3% of samples containing at least one of the 10 AMR genes assessed. CONCLUSION: This study demonstrates substantive PCV13 impact on pneumococcal carriage one year post-vaccine introduction in Mongolia. The reductions in PCV13 serotype carriage are likely to result in reductions in pneumococcal disease including indirect effects. Increases in non-PCV13 serotypes require further monitoring.
Authors: Claire von Mollendorf; Mukhchuluun Ulziibayar; Bradford D Gessner; Lien Anh Ha Do; Cattram D Nguyen; Rohini Beavon; Bujinlkham Suuri; Dashtseren Luvsantseren; Dorj Narangerel; Adam Jenney; Eileen M Dunne; Catherine Satzke; Badarchiin Darmaa; Tuya Mungun; E Kim Mulholland Journal: BMC Public Health Date: 2021-09-23 Impact factor: 3.295
Authors: Eileen M Dunne; Molina Choummanivong; Eleanor F G Neal; Kathryn Stanhope; Cattram D Nguyen; Anonh Xeuatvongsa; Catherine Satzke; Vanphanom Sychareun; Fiona M Russell Journal: PLoS One Date: 2019-10-29 Impact factor: 3.240
Authors: Jocelyn Chan; Tuya Mungun; Purevsuren Batsaixan; Mukhchuluun Ulziibayar; Bujinlkham Suuri; Dashpagam Otgonbayar; Dashtseren Luvsantseren; Cattram D Nguyen; Dorj Narangarel; Eileen M Dunne; Kimberley Fox; Jason Hinds; Monica L Nation; Casey L Pell; E Kim Mulholland; Catherine Satzke; Claire von Mollendorf; Fiona M Russell Journal: Lancet Reg Health West Pac Date: 2021-07-30