SummaryBackgroundLittle information is available about the effect of pneumococcal conjugate vaccines (PCVs) in low-income countries. We measured the effect of these vaccines on invasive pneumococcal disease in The Gambia where the 7-valent vaccine (PCV7) was introduced in August, 2009, followed by the 13-valent vaccine (PCV13) in May, 2011.MethodsWe conducted population-based surveillance for invasive pneumococcal disease in individuals aged 2 months and older who were residents of the Basse Health and Demographic Surveillance System (BHDSS) in the Upper River Region, The Gambia, using standardised criteria to identify and investigate patients. Surveillance was done between May, 2008, and December, 2014. We compared the incidence of invasive pneumococcal disease between baseline (May 12, 2008–May 11, 2010) and after the introduction of PCV13 (Jan 1, 2013–Dec 31, 2014), adjusting for changes in case ascertainment over time.FindingsWe investigated 14 650 patients, in whom we identified 320 cases of invasive pneumococcal disease. Compared with baseline, after the introduction of the PCV programme, the incidence of invasive pneumococcal disease decreased by 55% (95% CI 30–71) in the 2–23 months age group, from 253 to 113 per 100 000 population. This decrease was due to an 82% (95% CI 64–91) reduction in serotypes covered by the PCV13 vaccine. In the 2–4 years age group, the incidence of invasive pneumococcal disease decreased by 56% (95% CI 25–75), from 113 to 49 cases per 100 000, with a 68% (95% CI 39–83) reduction in PCV13 serotypes. The incidence of non-PCV13 serotypes in children aged 2–59 months increased by 47% (−21 to 275) from 28 to 41 per 100 000, with a broad range of serotypes. The incidence of non-pneumococcal bacteraemia varied little over time.InterpretationThe Gambian PCV programme reduced the incidence of invasive pneumococcal disease in children aged 2–59 months by around 55%. Further surveillance is needed to ascertain the maximum effect of the vaccine in the 2–4 years and older age groups, and to monitor serotype replacement. Low-income and middle-income countries that introduce PCV13 can expect substantial reductions in invasive pneumococcal disease.FundingGAVI's Pneumococcal vaccines Accelerated Development and Introduction Plan (PneumoADIP), Bill & Melinda Gates Foundation, and the UK Medical Research Council.
SummaryBackgroundPneumococcal conjugate vaccines (PCVs) are used in many low-income countries but their impact on the incidence of pneumonia is unclear. The Gambia introduced PCV7 in August, 2009, and PCV13 in May, 2011. We aimed to measure the impact of the introduction of these vaccines on pneumonia incidence.MethodsWe did population-based surveillance and case-control studies. The primary endpoint was WHO-defined radiological pneumonia with pulmonary consolidation. Population-based surveillance was for suspected pneumonia in children aged 2–59 months (minimum age 3 months in the case-control study) between May 12, 2008, and Dec 31, 2015. Surveillance for the impact study was limited to the Basse Health and Demographic Surveillance System (BHDSS), whereas surveillance for the case-control study included both the BHDSS and Fuladu West Health and Demographic Surveillance System. Nurses screened all outpatients and inpatients at all health facilities in the surveillance area using standardised criteria for referral to clinicians in Basse and Bansang. These clinicians recorded clinical findings and applied standardised criteria to identify patients with suspected pneumonia. We compared the incidence of pneumonia during the baseline period (May 12, 2008, to May 11, 2010) and the PCV13 period (Jan 1, 2014, to Dec 31, 2015). We also investigated the effectiveness of PCV13 using case-control methods between Sept 12, 2011, and Sept 31, 2014. Controls were aged 90 days or older, and were eligible to have received at least one dose of PCV13; cases had the same eligibility criteria with the addition of having WHO-defined radiological pneumonia.FindingsWe investigated 18 833 children with clinical pneumonia and identified 2156 cases of radiological pneumonia. Among children aged 2–11 months, the incidence of radiological pneumonia fell from 21·0 cases per 1000 person-years in the baseline period to 16·2 cases per 1000 person-years (23% decline, 95% CI 7–36) in 2014–15. In the 12–23 month age group, radiological pneumonia decreased from 15·3 to 10·9 cases per 1000 person-years (29% decline, 12–42). In children aged 2–4 years, incidence fell from 5·2 to 4·1 cases per 1000 person-years (22% decline, 1–39). Incidence of all clinical pneumonia increased by 4% (–1 to 8), but hospitalised cases declined by 8% (3–13). Pneumococcal pneumonia declined from 2·9 to 1·2 cases per 1000 person-years (58% decline, 22–77) in children aged 2–11 months and from 2·6 to 0·7 cases per 1000 person-years (75% decline, 47–88) in children aged 12–23 months. Hypoxic pneumonia fell from 13·1 to 5·7 cases per 1000 person-years (57% decline, 42–67) in children aged 2–11 months and from 6·8 to 1·9 cases per 1000 person-years (72% decline, 58–82) in children aged 12–23 months. In the case-control study, the best estimate of the effectiveness of three doses of PCV13 against radiological pneumonia was an adjusted odds ratio of 0·57 (0·30–1·08) in children aged 3–11 months and vaccine effectiveness increased with greater numbers of doses (p=0·026). The analy...
BackgroundRotavirus vaccines are now globally recommended by the World Health Organization (WHO), but in early 2009 WHO’s Strategic Advisory Group of Experts on Immunization reviewed available data and concluded that there was no evidence for the efficacy or effectiveness of a two-dose schedule of the human rotavirus vaccine (HRV; Rotarix) given early at 6 and 10 wk of age. Additionally, the effectiveness of programmatic rotavirus vaccination, including possible indirect effects, has not been assessed in low-resource populations in Asia.Methods and findingsIn Bangladesh, we cluster-randomized (1:1) 142 villages of the Matlab Health and Demographic Surveillance System to include two doses of HRV with the standard infant vaccines at 6 and 10 wk of age or to provide standard infant vaccines without HRV. The study was initiated November 1, 2008, and surveillance was conducted concurrently at Matlab Diarrhoea Hospital and two community treatment centers to identify children less than 2 y of age presenting with acute rotavirus diarrhea (ARD) through March 31, 2011. Laboratory confirmation was made by enzyme immunoassay detection of rotavirus antigen in stool specimens. Overall effectiveness of the HRV vaccination program (primary objective) was measured by comparing the incidence rate of ARD among all children age-eligible for vaccination in villages where HRV was introduced to that among such children in villages where HRV was not introduced. Total effectiveness among vaccinees and indirect effectiveness were also evaluated. In all, 6,527 infants were age-eligible for vaccination in 71 HRV villages, and 5,791 in 71 non-HRV villages. In HRV villages, 4,808 (73.7%) infants received at least one dose of HRV. The incidence rate of ARD was 4.10 cases per 100 person-years in non-HRV villages compared to 2.8 per 100 person-years in HRV villages, indicating an overall effectiveness of 29.0% (95% CI, 11.3% to 43.1%). The total effectiveness of HRV against ARD among vaccinees was 41.4% (95% CI, 23.2% to 55.2%). The point estimate for total effectiveness was higher against ARD during the first year of life than during the second (45.2% versus 28.9%), but estimates for the second year of life lacked precision and did not reach statistical significance. Indirect effects were not detected. To check for bias in presentation to treatment facilities, we evaluated the effectiveness of HRV against acute diarrhea associated with enterotoxigenic Escherichia coli; it was 4.0% (95% CI, −46.5% to 37.1%), indicating that bias likely was not introduced. Thirteen serious adverse events were identified among recipients of HRV, but none were considered related to receipt of study vaccine. The main limitation of this study is that it was an open-label study with an observed-only control group (no placebo).ConclusionsThe two-dose HRV rotavirus vaccination program significantly reduced medically attended ARD in this low-resource population in Asia. Protection among vaccinees was similar to that in other low-resource settings. In low-resource populat...
Background Anemia is one of the most impactful nutrient deficiencies in the world and disproportionately affects children in low-resource settings. Point-of-care devices (PoCDs) measuring blood hemoglobin (Hb) are widely used in such settings to screen for anemia due to their low cost, speed, and convenience. Here we present the first iteration of Aptus, a new PoCD which measures Hb and hematocrit (HCT). Aim To evaluate the accuracy of Aptus and HemoCue® Hb 301 against an automated hematology analyzer (Medonic®) in Gambian children aged 6-35 months and the Aptus' usage in the field. Methods Aptus, HemoCue® and Medonic® were compared using venous blood (n = 180), and Aptus and HemoCue® additionally using capillary blood (n = 506). Agreement was estimated using Bland-Altman analysis and Lin's concordance. Usage was assessed by error occurrence and user experience. Results Mean Hb values in venous blood did not significantly differ between Aptus and HemoCue® (10.44±1.05 vs 10.56±0.93g/dl, p>0.05), but both measured higher Hb concentrations than Medonic® (9.75±0.99g/dl, p<0.0001). Lin's coefficient between Aptus and Medonic® was r c = 0.548, between HemoCue® and Medonic® r c = 0.636. Mean bias between the PoCDs venous measurements was-0.11g/dl with limits of agreement (LoA)-1.63 and 1.40g/dl. The
Background The Gambia introduced seven-valent pneumococcal conjugate vaccine (PCV7) in August 2009, followed by PCV13 in May, 2011, using a schedule of three primary doses without a booster dose or catch-up immunisation. We aimed to assess the long-term impact of PCV on disease incidence. MethodsWe did 10 years of population-based surveillance for invasive pneumococcal disease (IPD) and WHO defined radiological pneumonia with consolidation in rural Gambia. The surveillance population included all Basse Health and Demographic Surveillance System residents aged 2 months or older. Nurses screened all outpatients and inpatients at all health facilities using standardised criteria for referral. Clinicians then applied criteria for patient investigation. We defined IPD as a compatible illness with isolation of Streptococcus pneumoniae from a normally sterile site (cerebrospinal fluid, blood, or pleural fluid). We compared disease incidence between baseline (May 12, 2008-May 11, 2010) and post-vaccine years (2016-2017), in children aged 2 months to 14 years, adjusting for changes in case ascertainment over time.Findings We identified 22 728 patients for investigation and detected 342 cases of IPD and 2623 cases of radiological pneumonia. Among children aged 2-59 months, IPD incidence declined from 184 cases per 100 000 person-years to 38 cases per 100 000 person-years, an 80% reduction (95% CI 69-87). Non-pneumococcal bacteraemia incidence did not change significantly over time (incidence rate ratio 0•88; 95% CI, 0•64-1•21). We detected zero cases of vaccine-type IPD in the 2-11 month age group in 2016-17. Incidence of radiological pneumonia decreased by 33% (95% CI 24-40), from 10•5 to 7•0 per 1000 person-years in the 2-59 month age group, while pneumonia hospitalisations declined by 27% (95% CI 22-31). In the 5-14 year age group, IPD incidence declined by 69% (95% CI -28 to 91) and radiological pneumonia by 27% (95% CI -5 to 49).Interpretation Routine introduction of PCV13 substantially reduced the incidence of childhood IPD and pneumonia in rural Gambia, including elimination of vaccine-type IPD in infants. Other low-income countries can expect substantial impact from the introduction of PCV13 using a schedule of three primary doses.
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