Effect of ten-valent pneumococcal conjugate vaccine introduction on pneumonia hospital admissions in Fiji: a time-series analysis

Abstract

Background In October, 2012, Fiji introduced routine infant immunisation with a ten-valent pneumococcal conjugate vaccine (PCV10) using three primary doses and no booster dose (3 + 0 schedule). Data are scarce for the effect of PCV in the Asia and Pacific region. We aimed to evaluate the effect of PCV10 on pneumonia hospital admissions in children younger than 5 years and adults aged 55 years and older in Fiji, 5 years after vaccine introduction. Methods We did a time-series analysis assessing changes in pneumonia hospital admissions at three public tertiary hospitals in Fiji. Four pneumonia outcomes were evaluated: all-cause pneumonia, severe or very severe pneumonia, hypoxic pneumonia, and radiological pneumonia. Participants aged younger than 2 months, 2-23 months, 24-59 months, and 55 years and older were included. Data were extracted from the national hospital admission database according to International Classification of Diseases-tenth revision codes J10•0-18•9, J21, and J22 for allcause pneumonia. Medical records and chest radiographs were reviewed for the main tertiary hospital to reclassify hospital admissions in children aged younger than 2 years as severe or very severe, hypoxic, or radiological pneumonia as per WHO definitions. Time-series analyses were done using the synthetic control method and multiple imputation to adjust for changes in hospital usage and missing data. Findings Between Jan 1, 2007, and Dec 31, 2017, the ratio of observed cases to expected cases for all-cause pneumonia was 0•92 (95% CI 0•70-1•36) for children aged younger than 2 months, 0•86 (0•74-1•00) for children aged 2-23 months, 0•74 (0•62-0•87) for children aged 24-59 months, and 1•90 (1•53-2•31) in adults aged 55 years and older, 5 years after PCV10 introduction. These findings indicate a reduction in all-cause pneumonia among children aged 24-59 months and an increase in adults aged 55 years and older, but no change among children aged younger than 2 months. Among children aged 2-23 months, we observed declines of 21% (95% CI 5-35) for severe or very severe pneumonia, 46% (33-56) for hypoxic pneumonia, and 25% (9-38) for radiological pneumonia. Mortality reduced by 39% (95% CI 5-62) for all-cause pneumonia, bronchiolitis, and asthma admissions in children aged 2-23 months. Interpretation The introduction of PCV10 was associated with a decrease in pneumonia hospital admissions in children aged 2-59 months. This is the first study in a middle-income country in the Asia and Pacific region to show the effect of PCV on pneumonia, filling gaps in the literature on the effects of PCV10 and 3 + 0 schedules. These data support decision making on PCV introduction for other low-income and middle-income countries in the region.

Pneumococcal vaccine effect on hospitalisation rates of pneumonia in children: A meta‐analysis

“…This meta-analysis study based on 20 studies evaluating the relationship between the effects of different types of pneumococcal conjugate vaccines compared with each other on the frequency of community-acquired pneumonia hospitalisations in children aged below 2 years. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] The pneumococcal conjugate vaccine 10 was significantly related to lower hospitalisation rate for pneumonia compared with no vaccine and pneumococcal conjugate vaccine 7; the pneumococcal conjugate vaccine 13 was significantly related to lower hospitalisation rate for pneumonia compared with no vaccine and pneumococcal conjugate vaccine 7; and finally, the pneumococcal conjugate vaccine 13 was significantly related to lower hospitalisation rate for pneumonia compared with pneumococcal conjugate vaccine 10.…”

“…A total of 3421 unique studies were identified, of which 20 studies, from 2013 until 2021 in humans, satisfied the inclusion criteria and were included in the study. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] = 94%), compared with pneumococcal conjugate vaccine 10 as shown in Figure 6.…”

“…A total of 3421 unique studies were identified, of which 20 studies, from 2013 until 2021 in humans, satisfied the inclusion criteria and were included in the study 17‐36 . Details of the included studies are shown in Table 2.…”

Evaluation strategies for measuring pneumococcal conjugate vaccine impact in low-resource settings

“…Missing data is common in routine administrative data. A study from Fiji using administrative data imputed missing data by multiple imputation [23].…”

ENT/Audiology Department of Samoa welcomes the introduction of the Pneumococcal Conjugate Vaccine (PCV) into the national childhood immunisation program.

“…The prevalence of vaccine-serotype carriage reduced among infants, toddlers, young children, and caregivers, and the density of PCV10 and non-PCV10-serotypes was significantly lower in PCV10-vaccinated 12-23-month-olds than their non-PCV10-vaccinated counterparts [ 8 ]. A time-series analysis also found a dramatic reduction in pneumonia hospital admissions following the introduction of the PCV10 for the 2-59 months age group [ 9 ]. The significant factors contributing to pneumococcal carriage and density continue to be young age, residential location, living with young children, low family income, and symptoms of upper respiratory tract infection [ 10 ].…”