Impact of the 13-Valent Pneumococcal Conjugate Vaccine on Clinical and Hypoxemic Childhood Pneumonia over Three Years in Central Malawi: An Observational Study

BACKGROUND

The pneumococcal conjugate vaccine's (PCV) impact on childhood pneumonia during programmatic conditions in Africa is poorly understood. Following PCV13 introduction in Malawi in November 2011, we evaluated the case burden and rates of childhood pneumonia.

METHODS AND FINDINGS

Between January 1, 2012-June 30, 2014 we conducted active pneumonia surveillance in children <5 years at seven hospitals, 18 health centres, and with 38 community health workers in two districts, central Malawi. Eligible children had clinical pneumonia per Malawi guidelines, defined as fast breathing only, chest indrawing +/- fast breathing, or, ≥1 clinical danger sign. Since pulse oximetry was not in the Malawi guidelines, oxygenation <90% defined hypoxemic pneumonia, a distinct category from clinical pneumonia. We quantified the pneumonia case burden and rates in two ways. We compared the period immediately following vaccine introduction (early) to the period with >75% three-dose PCV13 coverage (post). We also used multivariable time-series regression, adjusting for autocorrelation and exploring seasonal variation and alternative model specifications in sensitivity analyses. The early versus post analysis showed an increase in cases and rates of total, fast breathing, and indrawing pneumonia and a decrease in danger sign and hypoxemic pneumonia, and pneumonia mortality. At 76% three-dose PCV13 coverage, versus 0%, the time-series model showed a non-significant increase in total cases (+47%, 95% CI: -13%, +149%, p = 0.154); fast breathing cases increased 135% (+39%, +297%, p = 0.001), however, hypoxemia fell 47% (-5%, -70%, p = 0.031) and hospital deaths decreased 36% (-1%, -58%, p = 0.047) in children <5 years. We observed a shift towards disease without danger signs, as the proportion of cases with danger signs decreased by 65% (-46%, -77%, p<0.0001). These results were generally robust to plausible alternative model specifications.

CONCLUSIONS

Thirty months after PCV13 introduction in Malawi, the health system burden and rates of the severest forms of childhood pneumonia, including hypoxemia and death, have markedly decreased.

Peripheral blood RNA gene expression in children with pneumococcal meningitis: a prospective case-control study

INTRODUCTION

Invasive pneumococcal disease (IPD), caused by Streptococcus pneumoniae, is a leading cause of pneumonia, meningitis and septicaemia worldwide, with increased morbidity and mortality in HIV-infected children.

OBJECTIVES

We aimed to compare peripheral blood expression profiles between HIV-infected and uninfected children with pneumococcal meningitis and controls, and between survivors and non-survivors, in order to provide insight into the host inflammatory response leading to poorer outcomes.

DESIGN AND SETTING

Prospective case-control observational study in a tertiary hospital in Malawi.

PARTICIPANTS

Children aged 2 months to 16 years with pneumococcal meningitis or pneumonia.

METHODS

We used the human genome HGU133A Affymetrix array to explore differences in gene expression between cases with pneumococcal meningitis (n=12) and controls, and between HIV-infected and uninfected cases, and validated gene expression profiles for 34 genes using real-time quantitative PCR (RT-qPCR) in an independent set of cases with IPD (n=229) and controls (n=13). Pathway analysis was used to explore genes differentially expressed.

RESULTS

Irrespective of underlying HIV infection, cases showed significant upregulation compared with controls of the following: S100 calcium-binding protein A12 (S100A12); vanin-1 (VNN1); arginase, liver (ARG1); matrix metallopeptidase 9 (MMP9); annexin A3 (ANXA3); interleukin 1 receptor, type II (IL1R2); CD177 molecule (CD177); endocytic adaptor protein (NUMB) and S100 calcium-binding protein A9 (S100A9), cytoskeleton-associated protein 4 (CKAP4); and glycogenin 1 (GYG1). RT-qPCR confirmed differential expression in keeping with microarray results. There was no differential gene expression in HIV-infected compared with HIV-uninfected cases, but there was significant upregulation of folate receptor 3 (FOLR3), S100A12 in survivors compared with non-survivors.

CONCLUSION

Children with IPD demonstrated increased expression in genes regulating immune activation, oxidative stress, leucocyte adhesion and migration, arginine metabolism, and glucocorticoid receptor signalling.

Non-adherence to community oral-antibiotic treatment in children with fast-breathing pneumonia in Malawi- secondary analysis of a prospective cohort study

Background

Despite significant progress, pneumonia is still the leading cause of infectious deaths in children under five years of age. Poor adherence to antibiotics has been associated with treatment failure in World Health Organisation (WHO) defined clinical pneumonia; therefore, improving adherence could improve outcomes in children with fast-breathing pneumonia. We examined clinical factors that may affect adherence to oral antibiotics in children in the community setting in Malawi.

Methods

We conducted a sub-analysis of a prospective cohort of children aged 2–59 months diagnosed by community health workers (CHW) in rural Malawi with WHO fast-breathing pneumonia. Clinical factors identified during CHW diagnosis were investigated using multivariate logistic regression for association with non-adherence, including concurrent diagnoses and treatments. Adherence was measured at both 80% and 100% completion of prescribed oral antibiotics.

Results

Eight hundred thirty-four children were included in our analysis, of which 9.5% and 20.0% were non-adherent at 80% and 100% of treatment completion, respectively. A concurrent infectious diagnosis (OR: 1.76, 95% CI: 0.84–2.96/OR: 1.81, 95% CI: 1.21–2.71) and an illness duration of >24 h prior to diagnosis (OR: 2.14, 95% CI: 1.27–3.60/OR: 1.88, 95% CI: 1.29–2.73) had higher odds of non-adherence when measured at both 80% and 100%. Older age was associated with lower odds of non-adherence when measured at 80% (OR: 0.41, 95% CI: 0.21–0.78).

Conclusion

Non-adherence to oral antibiotics was not uncommon in this rural sub-Saharan African setting. As multiple diagnoses by the CHW and longer illness were important factors, this provides an opportunity for further investigation into targeted interventions and refinement of referral guidelines at the community level. Further research into the behavioural drivers of non-adherence within this setting is needed.

Non-treatment of children with community health worker-diagnosed fast-breathing pneumonia in rural Malawi: exploratory subanalysis of a prospective cohort study

BACKGROUND

Despite recent progress, pneumonia remains the largest infectious killer of children globally. This paper describes outcomes of not treating community-diagnosed fast-breathing pneumonia on patient recovery.

METHODS

We conducted an exploratory subanalysis of an observational prospective cohort study in Malawi. We recruited children (2-59 months) diagnosed by community health workers with fast-breathing pneumonia using WHO integrated community case management (iCCM) guidelines. Children were followed at days 5 and 14 with a clinical assessment of recovery. We conducted bivariate and multivariable logistic regression for the association between treatment of fast-breathing pneumonia and recovery, adjusting for potential confounders.

RESULTS

We followed up 847 children, of whom 78 (9%) had not been given antibiotics (non-treatment). Non-treatment cases had higher baseline rates of diarrhoea, non-severe hypoxaemia and fever. Non-recovery (persistence or worsening of symptoms) was 13% and 23% at day 5 in those who did receive and those who did not receive co-trimoxazole. Non-recovery, when defined as worsening of symptoms only, at day 5 was 7% in treatment and 10% in non-treatment cases. For both definitions, combined co-trimoxazole and lumefantrine-artemether (LA) treatment trended towards protection (adjusted OR (aOR) 0.28; 95% CI 0.12 to 0.68/aOR 0.29; 95% CI 0.08 to 1.01).

CONCLUSION

We found that children who did not receive co-trimoxazole treatment had worse clinical outcomes; malaria co-diagnosis and treatment also play a significant role in non-recovery. Further research into non-treatment of fast-breathing pneumonia, using a pragmatic approach with consideration for malaria co-diagnosis and HIV status is needed to guide refinement of community treatment algorithms in this region.

Pulse oximetry for children with pneumonia treated as outpatients in rural Malawi

OBJECTIVE

To investigate implementation of outpatient pulse oximetry among children with pneumonia, in Malawi.

METHODS

In 2011, 72 health-care providers at 18 rural health centres and 38 community health workers received training in the use of pulse oximetry to measure haemoglobin oxygen saturations. Data collected, between 1 January 2012 and 30 June 2014 by the trained individuals, on children aged 2-59 months with clinically diagnosed pneumonia were analysed.

FINDINGS

Of the 14 092 children included in the analysis, 13 266 (94.1%) were successfully checked by oximetry. Among the children with chest indrawing and/or danger signs, those with a measured oxygen saturation below  90% were more than twice as likely to have been referred as those with higher saturations (84.3% [385/457] vs 41.5% [871/2099]; P < 0.001). The availability of oximetry appeared to have increased the referral rate for severely hypoxaemic children without chest indrawing or danger signs from 0% to 27.2% (P < 0.001). In the absence of oximetry, if the relevant World Health Organization (WHO) guidelines published in 2014 had been applied, 390/568 (68.7%) severely hypoxaemic children at study health centres and 52/84 (61.9%) severely hypoxaemic children seen by community health workers would have been considered ineligible for referral.

CONCLUSION

Implementation of pulse oximetry by our trainees substantially increased the referrals of Malawian children with severe hypoxaemic pneumonia. When data from oximetry were excluded, retrospective application of the guidelines published by WHO in 2014 failed to identify a considerable proportion of severely hypoxaemic children eligible only via oximetry.

Can We Predict Oral Antibiotic Treatment Failure in Children with Fast-Breathing Pneumonia Managed at the Community Level? A Prospective Cohort Study in Malawi

BACKGROUND

Pneumonia is the leading cause of infectious death amongst children globally, with the highest burden in Africa. Early identification of children at risk of treatment failure in the community and prompt referral could lower mortality. A number of clinical markers have been independently associated with oral antibiotic failure in childhood pneumonia. This study aimed to develop a prognostic model for fast-breathing pneumonia treatment failure in sub-Saharan Africa.

METHOD

We prospectively followed a cohort of children (2-59 months), diagnosed by community health workers with fast-breathing pneumonia using World Health Organisation (WHO) integrated community case management guidelines. Cases were followed at days 5 and 14 by study data collectors, who assessed a range of pre-determined clinical features for treatment outcome. We built the prognostic model using eight pre-defined parameters, using multivariable logistic regression, validated through bootstrapping.

RESULTS

We assessed 1,542 cases of which 769 were included (32% ineligible; 19% defaulted). The treatment failure rate was 15% at day 5 and relapse was 4% at day 14. Concurrent malaria diagnosis (OR: 1.62; 95% CI: 1.06, 2.47) and moderate malnutrition (OR: 1.88; 95% CI: 1.09, 3.26) were associated with treatment failure. The model demonstrated poor calibration and discrimination (c-statistic: 0.56).

CONCLUSION

This study suggests that it may be difficult to create a pragmatic community-level prognostic child pneumonia tool based solely on clinical markers and pulse oximetry in an HIV and malaria endemic setting. Further work is needed to identify more accurate and reliable referral algorithms that remain feasible for use by community health workers.

Lactate as a predictor of mortality in Malawian children with WHO-defined pneumonia

OBJECTIVES

To determine whether blood lactate measured at the time of presentation to hospital predicted outcome in children with pneumonia in Malawi, and to understand the factors associated with high blood lactate concentrations in pneumonia.

DESIGN

Analysis of data from a prospective study of children presenting to Queen Elizabeth Central Hospital, Blantyre, with WHO-defined severe or very severe pneumonia.

RESULTS

Among 233 children with pneumonia, the median serum lactate concentration was 2.7 mmol/l (IQR 1.8-4.4 mmol/l). 77 children (33%) had a lactate concentration of 2.1-4.0 mmol/l, and 72 children (31%) had a lactate concentration >4.0 mmol/l. 92% of children who died (23/25) had lactate >2.0 mmol/l at the time of admission to hospital. There were 10 deaths (13%) among 77 children who had a serum lactate concentration of 2.1-4.0 mmol/l; and 13 deaths (18%) in the 72 children who had lactate >4.0 mmol/l. The relative risk of death if the lactate level was above 2 mmol/l was 7.48 (1.72-32.6); sensitivity 0.92, specificity 0.39, positive predictive value 0.15, negative predictive value 0.98. Multivariable analysis showed that hypoxaemia, hyperlactataemia and age ≤12 months were independent risk factors for death from pneumonia.

CONCLUSIONS

Used in conjunction with clinical risk factors and pulse oximetry for measuring oxygen saturation, lactate could play an important role in identifying the sickest patients with pneumonia in developing countries.

Brain abscesses in Malawian children: value of CT scan

The clinical presentation and management of brain abscess in three HIV-uninfected Malawian children are reported. One case was associated with staphylococcal empyema and severe malarial anaemia and another case with chronic suppurative otitis media and mastoiditis. The third case had no identified extracranial focus of infection. These cases illustrate the difficulties of diagnosis and management of brain abscesses in the resource-poor setting where other causes of encephalopathy caused by infection are common, and highlight the value of neuroradiological imaging.

A case series of brain abscesses in Malawian children

We report three cases of brain abscess in children admitted to QECH in 2006. All children were HIV-uninfected. One case was associated with staphylococcal empyema, another with chronic suppurative otitis media and mastoiditis, and the third case had no identified extracranial focus of infection. These cases illustrate the difficulties of diagnosis and management of brain abscesses in the resource-poor setting where other causes of infection of the central nervous system are common. The typical clinical presentation of brain abscess of altered mental state and seizures is also characteristic of cerebral malaria and meningitis and it is likely that many cases of brain abscess in Malawian children are not diagnosed. The value of cranial CT scan, ideally with contrast, for diagnosis and management of brain abscess is highlighted by these cases.

Rabies encephalitis in malaria-endemic area, Malawi, Africa

In a malaria-endemic area of Africa, rabies was an important cause of fatal central nervous system infection, responsible for 14 (10.5%) of 133 cases. Four patients had unusual clinical manifestations, and rabies was only diagnosed postmortem. Three (11.5%) of 26 fatal cases were originally attributed to cerebral malaria.

Scaling up of highly active antiretroviral therapy in a rural district of Malawi: an effectiveness assessment

BACKGROUND

The recording of outcomes from large-scale, simplified HAART (highly active antiretroviral therapy) programmes in sub-Saharan Africa is critical. We aimed to assess the effectiveness of such a programme held by Médecins Sans Frontières (MSF) in the Chiradzulu district, Malawi.

METHODS

We scaled up and simplified HAART in this programme since August, 2002. We analysed survival indicators, CD4 count evolution, virological response, and adherence to treatment. We included adults who all started HAART 6 months or more before the analysis. HIV-1 RNA plasma viral load and self-reported adherence were assessed on a subsample of patients, and antiretroviral resistance mutations were analysed in plasma with viral loads greater than 1000 copies per mL. Analysis was by intention to treat.

FINDINGS

Of the 1308 patients who were eligible, 827 (64%) were female, the median age was 34.9 years (IQR 29.9-41.0), and 1023 (78%) received d4T/3TC/NVP (stavudine, lamivudine, and nevirapine) as a fixed-dose combination. At baseline, 1266 individuals (97%) were HAART-naive, 357 (27%) were at WHO stage IV, 311 (33%) had a body-mass index of less than 18.5 kg/m2, and 208 (21%) had a CD4 count lower than 50 cells per muL. At follow-up (median 8.3 months, IQR 5.5-13.1), 967 (74%) were still on HAART, 243 (19%) had died, 91 (7%) were lost to follow-up, and seven (0.5%) discontinued treatment. Low body-mass index, WHO stage IV, male sex, and baseline CD4 count lower than 50 cells per muL were independent determinants of death in the first 6 months. At 12 months, the probability of individuals still in care was 0.76 (95% CI 0.73-0.78) and the median CD4 gain was 165 (IQR 67-259) cells per muL. In the cross-sectional survey (n=398), 334 (84%) had a viral load of less than 400 copies per mL. Of several indicators measuring adherence, self-reported poor adherence (<80%) in the past 4 days was the best predictor of detectable viral load (odds ratio 5.4, 95% CI 1.9-15.6).

INTERPRETATION

These data show that large numbers of people can rapidly benefit from antiretroviral therapy in rural resource-poor settings and strongly supports the implementation of such large-scale simplified programmes in Africa.

Evaluation of the OptiMAL rapid antigen test and species-specific PCR to detect placental Plasmodium falciparum infection at delivery

During pregnancy, Plasmodium falciparum infection of the placenta frequently occurs in the absence of parasites in peripheral blood. We investigated the abilities of the OptiMAL rapid immunochromatographic strip test for P. falciparum lactate dehydrogenase and species-specific PCR performed on peripheral blood to detect placental infection or malaria-associated low birth weight. Of 509 Malawian women screened by microscopy, 76 had malaria infection. Among these 509 women, the frequency of peripheral blood parasitemia was low. The OptiMAL test gave positive results in 37 of 171 women tested (one of whom had placental but not peripheral blood parasitemia) and had sensitivities of 71% for peripheral parasitemia and 38% for placental parasitemia compared to the microscopy values. The specificity for peripheral parasitemia was 94%. In 135 women, PCR had sensitivities of 94% for peripheral blood malaria detected by microscopy and 72% for placental infection. In samples examined by PCR, the prevalence of malaria in peripheral blood increased from 26.7% by microscopy to 51.9%. Women with placental malaria and women with malaria in peripheral blood samples by microscopy or OptiMAL testing, but not women with malaria detected only by PCR, had lower-birth-weight babies than did women without malaria by these criteria. Positive results by PCR in the absence of microscopic parasitemia were not associated with low birth weight. Neither OptiMAL nor PCR testing of peripheral blood is adequately sensitive to detect all placental malaria infection, but a positive result by OptiMAL testing identifies women with a high proportion of low-birth-weight babies.