Abstract
Background
WHO recommends a three-dose infant pneumococcal conjugate vaccine (PCV) schedule administered as a two-dose primary series with booster (2 + 1) or a three-dose primary series (3 + 0). Data on carriage impacts of these and further reduced PCV schedules are needed to inform PCV strategies. Here we evaluate the efficacy against carriage of four different PCV10 schedules.
Methods
Participants within an open-label, randomised controlled trial in Ho Chi Minh City, Vietnam, were allocated to receive PCV10 in a 3 + 1 (2,3,4,9 months, n = 152), 3 + 0 (2,3,4 months, n = 149), 2 + 1 (2,4,9.5 months, n = 250) or novel two-dose (2,6 months, n = 202) schedule, or no infant doses of PCV (two control groups, n = 197 and n = 199). Nasopharyngeal swabs collected between 2 and 24 months were analysed (blinded) for pneumococcal carriage and serotypes. Trial registration: ClinicalTrials.gov NCT01953510.
Findings
Pneumococcal carriage prevalence was low (10.6–14.1% for vaccine-type (VT) at 12–24 months in unvaccinated controls). All four PCV10 schedules reduced VT carriage compared with controls (the 2 + 1 schedule at 12, 18, and 24 months; the 3 + 1 and two-dose schedules at 18 months; and the 3 + 0 schedule at 24 months), with maximum reductions of 40.1%–64.5%. There were no differences in VT carriage prevalence at 6 or 9 months comparing three-dose and two-dose primary series, and no differences at 12, 18, or 24 months when comparing schedules with and without a booster dose.
Interpretation
In Vietnamese children with a relatively low pneumococcal carriage prevalence, 3 + 1, 2 + 1, 3 + 0 and two-dose PCV10 schedules were effective in reducing VT carriage. There were no discernible differences in the effect on carriage of the WHO-recommended 2 + 1 and 3 + 0 schedules during the first two years of life. Together with the previously reported immunogenicity data, this trial suggests that a range of PCV schedules are likely to generate significant direct and indirect protection.
| Original language | English |
|---|---|
| Article number | 100651 |
| Pages (from-to) | 1-10 |
| Number of pages | 10 |
| Journal | The Lancet Regional Health - Western Pacific |
| Volume | 32 |
| Early online date | 2022 |
| DOIs | |
| Publication status | Published - Mar 2023 |
Bibliographical note
Funding Information:We thank the study participants and their families, the study staff, and the laboratory staff from the Pasteur Institute of Ho Chi Minh City, the Menzies Child Health team, and the MCRI Translational Microbiology Group. We acknowledge the contributions of Dang Duc Anh, Nguyen Thi Hien Anh, Jonathan Carapetis, Nguyen Thi Kieu Chinh, Lam Trung Duc, Katherine Gould, William Hausdorff, Bernard Hoet, Vu Thi Que Huong (deceased), Tran Thi Kim Ngan, Peter Paradiso, Nguyen Thi Minh Phuong (deceased), Fiona Russell, and Lay Myint Yoshida. We also acknowledge the Victorian Government's Operational Infrastructure Support Program. This work was supported by the National Health and Medical Research Council of Australia (grant number 566792 ) and the Bill & Melinda Gates Foundation (grant number OPP1116833 ). PCV10 vaccine doses were donated by GlaxoSmithKline Biological SA.
Publisher Copyright:
© 2022 The Author(s)