Rationale and methods of a randomized controlled trial of immunogenicity, safety and impact on carriage of pneumococcal conjugate and polysaccharide vaccines in infants in Papua New Guinea

Deborah Lehmann,Lea-Ann Kirkham,Andrew Greenhill,Wendy Kirarock,Birunu Nivio,Anita H J Van Den Biggelaar,Gerard Saleu,Megan Passey,Peter C Richmond,Vela Solomon,Geraldine Masiria,William S Pomat,Tilda Orami,Peter Jacoby,Jacinta Francis,Rebecca Ford

doi:10.1186/s41479-017-0044-z

Abstract

BackgroundChildren in third-world settings including Papua New Guinea (PNG) experience early onset of carriage with a broad range of pneumococcal serotypes, resulting in a high incidence of severe pneumococcal disease and deaths in the first 2 years of life. Vaccination trials in high endemicity settings are needed to provide evidence and guidance on optimal strategies to protect children in these settings against pneumococcal infections.MethodsThis report describes the rationale, objectives, methods, study population, follow-up and specimen collection for a vaccination trial conducted in an endemic and logistically challenging setting in PNG. The trial aimed to determine whether currently available pneumococcal conjugate vaccines (PCV) are suitable for use under PNG’s accelerated immunization schedule, and that a schedule including pneumococcal polysaccharide vaccine (PPV) in later infancy is safe and immunogenic in this high-risk population.ResultsThis open randomized-controlled trial was conducted between November 2011 and March 2016, enrolling 262 children aged 1 month between November 2011 and April 2014. The participants were randomly allocated (1:1) to receive 10-valent PCV (10vPCV) or 13-valent PCV (13vPCV) in a 1-2-3-month schedule, with further randomization to receive PPV or no PPV at age 9 months, followed by a 1/5th PPV challenge at age 23 months. A total of 1229 blood samples were collected to measure humoral and cellular immune responses and 1238 nasopharyngeal swabs to assess upper respiratory tract colonization and carriage load. Serious adverse events were monitored throughout the study. Of the 262 children enrolled, 87% received 3 doses of PCV, 79% were randomized to receive PPV or no PPV at age 9 months, and 67% completed the study at 24 months of age with appropriate immunization and challenge.ConclusionLaboratory testing of the many samples collected during this trial will determine the impact of the different vaccine schedules and formulations on nasopharyngeal carriage, antibody production and function, and immune memory. The final data will inform policy on pneumococcal vaccine schedules in countries with children at high risk of pneumococcal disease by providing direct comparison of an accelerated schedule of 10vPCV and 13vPCV and the potential advantages of PPV following PCV immunization.Trial registrationClinicalTrials.gov CTN NCT01619462, retrospectively registered on May 28, 2012

Highlights

Children in third-world settings including Papua New Guinea (PNG) experience early onset of carriage with a broad range of pneumococcal serotypes, resulting in a high incidence of severe pneumococcal disease and deaths in the first 2 years of life
262 children were formally enrolled into the study between 14 November 2011 and 16 April 2014, including 131 children randomized to receive 10-valent pneumococcal conjugate vaccines (PCV) (10vPCV) and 131 randomized to receive 13-valent PCV (13vPCV)
A flow chart (Fig. 1) shows the number of women who assented, number of infants randomized to receive one or other PCV at 1 month of age, number of children seen at subsequent visits, number of withdrawals and reasons for withdrawal according to randomization schedule

Summary

Introduction

Children in third-world settings including Papua New Guinea (PNG) experience early onset of carriage with a broad range of pneumococcal serotypes, resulting in a high incidence of severe pneumococcal disease and deaths in the first 2 years of life. In Papua New Guinea (PNG), acute lower respiratory infection (ALRI) is the most common reason for hospitalization and cause of death in children [3, 4] and the burden of invasive pneumococcal disease (IPD) remains high. The distribution of pneumococcal serotypes in PNG is broad: in our 7vPCV trial more than 60 different pneumococcal serotypes were identified in the URT of infants followed from birth until 18 months of age, of which 53 were identified in the first month of life [8, 9]. 43% of pneumococcal carriage isolates among controls who had not received PCV would have been covered by 13vPCV [8]

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Conclusion