Taking stock of global immunisation coverage progress: the gains, the losses and the journey ahead

Despite the enormous benefits of vaccination, global immunisation coverage progress has stalled and remains suboptimal in many countries. In this commentary, we review the recently published update of the World Health Organization and United Nations Children's Fund Estimates of National Immunization Coverage. We highlight trends in which, despite substantial gains made in improving immunisation coverage at the global level, there remain numerous challenges with reaching and sustaining optimal coverage. We contextualise the trends by exploring plausible supply- and demand-side root causes. Based on these, we stress the need for targeted, context-appropriate strategies for reaching and maintaining optimal immunisation coverage.

Rubella seroprevalence using residual samples from the South African measles surveillance program: a cross-sectional analytic study

Introduction: South Africa is yet to introduce rubella-containing vaccines (RCV) into its routine immunization schedule. Selecting the target population when introducing RCV should take into account the ages of susceptible individuals in the population. We aimed to determine the seroprevalence of antibodies to rubella and characterize immunity gaps among individuals of all ages in South Africa. Methods: We tested for rubella immunoglobulin G (IgG) antibodies with a commercial enzyme-linked immunosorbent assay. We used residual samples collected from 2016 through 2018 as part of the national measles surveillance program. We only tested samples that were negative for measles and rubella immunoglobulin M (IgM) and explored the association between rubella susceptibility (IgG negative) and predictor variables (year of sample collection, age, sex, and province of residence) using logistic regression analysis. Results: We obtained results for 6057 records. Rubella susceptibility was highest among Individuals aged zero to 11 months (81.9%), followed by children 1 to 5 years old (71.5%), 6 to 10 y old (40.9%) and 11 to 15 y old (31.25) while the smallest proportion of susceptible individuals was among those 16 to 49 y old (19.9%). Females were less likely to be susceptible to rubella compared to males (OR = 0.79 (95%CI: 0.71-0.87), P < .001) in unadjusted analysis but this effect was not observed after adjusting for age and province. In multivariable logistic regression, age (OR = 6.24 (4.52-8.63), P < .001) and province of residence (OR = 0.97 (95%CI: 0.95-0.99), P = .01) were associated with rubella susceptibility. Conclusion: In the absence of rubella vaccination in the Expanded Program on Immunization in South Africa, the bulk of individuals susceptible to rubella are children under 16 y old. About 20% of individuals 16 to 49 y old are susceptible to rubella. This susceptibility gap must be born in mind during RCV introduction.

Convalescent plasma or hyperimmune immunoglobulin for people with COVID-19

Convalescent plasma is being considered as a potential therapy for COVID-19. We highlight and contextualise the findings of a recent Cochrane rapid review that evaluated the effectiveness and safety of convalescent plasma or hyperimmune immunoglobulin transfusion in the treatment of people with COVID-19. The review found low-certainty evidence of the therapeutic effectiveness and safety of convalescent plasma. As the novel coronavirus continues to spread in South Africa (SA), convalescent plasma may offer a therapeutic ray of hope for mitigating the morbidity and mortality burdens of the disease. Further investigation of the clinical benefits of the therapy in well-designed studies is needed to provide more evidence that will guide COVID-19 treatment decision-making in the SA context.

Sputum induction for the diagnosis of pulmonary tuberculosis: a systematic review and meta-analysis

Sputum induction (SI) has been proposed as the optimal sample collection method for patients with paucibacillary tuberculosis (TB). Studies reporting the culture of Mycobacterium tuberculosis from SI were reviewed. A random-effects meta-analysis of diagnostic yield (numerator M. tuberculosis SI culture-positive cases; denominator all culture-positive cases) was conducted. Diagnostic yields (95% confidence intervals, CIs) were displayed as Forest plots. Heterogeneity was evaluated using Chi-squared and I-squared tests and meta-regression analysis. Ninety publications were screened, 28 full-text papers reviewed, and 17 analyzed. Collectively, n=627 SI culture-positive cases among n=975 culture-confirmed TB cases were reported. The diagnostic yield of SI ranged from 35 to 95%. The pooled diagnostic yield was 74% (CI 65-81%), with significant heterogeneity (p<0.0001, I2=86%). There were no statistically significant differences in the yield between sub-groups defined by human immunodeficiency virus (HIV) prevalence or age. Univariate analysis demonstrated that the use of fiberoptic bronchoscopy (FOB) as the comparator method was associated with a 22% reduction (CI 2-42%) in the diagnostic yield of SI. However, after adjustment for confounding, the meta-regression analysis showed that FOB usage (p=0.21) and saline concentration (p=0.31) were not independently associated with the diagnostic yield. SI will detect approximately three-quarters of M. tuberculosis culture-positive cases under study conditions. Significant heterogeneity in the diagnostic yield was not explained by HIV prevalence, age, or the use of FOB as the comparator method. The use of a particular nebulized saline concentration for SI cannot be recommended on the basis of this meta-regression analysis.

A systematic review of randomized controlled trials to reduce hemorrhage during myomectomy for uterine fibroids

OBJECTIVE

To assess the effectiveness and safety of interventions to reduce blood loss during myomectomy.

METHODS

Electronic searches of the Cochrane Library, MEDLINE, and EMBASE, between 1966 and 2006 for randomized controlled trials (RCTs).

RESULTS

We found significant reductions in blood loss with vaginal misoprostol (weighted mean difference [WMD] -149.00 mL, 95% confidence interval [CI] -229.24 to -68.76); intramyometrial vasopressin and analogues (WMD -298.72 mL, 95% CI -593.10 to -4.34); intramyometrial bupivacaine plus epinephrine (WMD -68.60 mL, 95% CI -93.69 to -43.51); and pericervical tourniquet (WMD -1870.00 mL, 95% CI -2547.16 to -1192.84). There was no evidence of effect in blood loss with myoma enucleation by morcellation and oxytocin.

CONCLUSION

There is limited evidence from a few RCTs that some interventions may reduce bleeding during myomectomy. There is need for adequately powered RCTs to shed more light on the effectiveness, safety, and cost of different interventions to reduce blood loss during myomectomy.

Interventions to reduce haemorrhage during myomectomy for fibroids

BACKGROUND

Uterine myomas (fibroids) are benign tumours of the uterus. Myomectomy, the surgical removal of the myomas, is an important treatment option especially for women who desire to preserve their uteri. The major problem with myomectomy is excessive bleeding from increased uterine blood supply, and this can be life-threatening and prolong postoperative stay. Knowledge of the effectiveness of the interventions used to reduce blood loss during myomectomy is essential to enable evidence-based clinical decisions.

OBJECTIVES

To assess the effectiveness and safety of interventions (other than GnRH analogues) to reduce blood loss during myomectomy.

SEARCH STRATEGY

Electronic searches were undertaken in the Cochrane Menstrual Disorders and Subfertility Group specialised register, CENTRAL (Cochrane Library Issue 1, 2006), MEDLINE (1966 to March 2006), EMBASE (1980 to March 2006), Current Contents (1993 to March 2006), the National Research Register, and the National Library of Medicine's Clinical Trial Register (up to March 2006).

SELECTION CRITERIA

Only randomised controlled trials (RCTs) that compared interventions to reduce blood loss during myomectomy to placebo or no treatment were included.

DATA COLLECTION AND ANALYSIS

The two authors independently selected RCTs for inclusion, assessed the methodological quality and extracted data. We expressed study results as weighted mean differences (WMD) for continuous data, and odds ratios for dichotomous data.

MAIN RESULTS

Eight RCTs met the inclusion criteria: two on intramyometrial vasopressin and analogues, and one each on vaginal misoprostol, IV oxytocin, pericervical tourniquet, chemical dissection with mesna, intramyometrial bupivacaine plus epinephrine and the enucleation of myoma by morcellation while it is attached to the uterus. We found significant reductions in blood loss with misoprostol (WMD -149.00 ml, 95% confidence interval [CI] -229.24 to -68.76), vasopressin and analogues (WMD -298.72 ml, 95% CI -593.10 to -4.34), bupivacaine plus epinephrine (WMD -68.60 ml, 95% CI -93.69 to - 43.51), and pericervical tourniquet (WMD -1870.00 ml, 95% CI -2547.16 to -1192.84). There was no evidence of effect in blood loss with myoma enucleation by morcellation and oxytocin. The trials did not assess the tolerability and costs of different interventions.

AUTHORS' CONCLUSIONS

There is limited evidence from a few RCTs that misoprostol, vasopressin, bupivacaine plus epinephrine, tourniquet and mesna may reduce bleeding during myomectomy. There is no evidence that oxytocin and morcellation have an effect on intraoperative blood loss. There is need for adequately powered RCTs to shed more light on the effectiveness, safety and costs of different interventions in reducing blood loss during myomectomy.

Beta-blockers for hypertension

BACKGROUND

Two recent systematic reviews found first-line beta-blockers to be less effective in reducing the incidence of stroke and the combined endpoint of stroke, myocardial infarction, and death compared to all other antihypertensive drugs taken together. However, beta-blockers might be better or worse than a specific class of drugs for a particular outcome measure so that comparing beta-blockers with all other classes taken together could be misleading. In addition, these systematic reviews did not assess the tolerability of beta-blockers relative to other antihypertensive medications. We thus undertook this review to re-assess the place of beta-blockade as first-line therapy for hypertension relative to each of the other major classes of antihypertensive drugs.

OBJECTIVES

To quantify the effectiveness and safety of beta-blockers on morbidity and mortality endpoints in adults with hypertension.

SEARCH STRATEGY

We searched eligible studies up to June 2006 in the Cochrane Controlled Trials Register, Medline, Embase, and reference lists of previous reviews, and by contacting hypertension experts.

SELECTION CRITERIA

We selected randomised controlled trials which assessed the effectiveness of beta-blockers compared to placebo, no therapy or other drug classes, as monotherapy or first-line therapy for hypertension, on mortality and morbidity endpoints in men and non-pregnant women aged 18 years or older.

DATA COLLECTION AND ANALYSIS

At least two authors independently applied study selection criteria, assessed study quality, and extracted data; with differences resolved by consensus. We expressed study results as relative risks (RR) with 95% confidence intervals (CI) and conducted quantitative analyses with trial participants in groups to which they were randomly allocated, regardless of which or how much treatment they actually received. In the absence of significant heterogeneity between studies (p>0.1), we performed meta-analysis using a fixed effects method. Otherwise, we used the random effects method and investigated the cause of heterogeneity by stratified analysis. In addition, we used the Higgins statistic (I(2)) to quantify the amount of between-study variability in effect attributable to true heterogeneity rather than chance.

MAIN RESULTS

Thirteen randomised controlled trials (N=91,561 participants), which met our inclusion criteria, compared beta-blockers to placebo or no treatment (4 trials with 23,613 participants), diuretics (5 trials with 18,241 participants), calcium-channel blockers (CCBs: 4 trials with 44,825 participants), and renin-angiotensin system (RAS) inhibitors (3 trials with 10,828 participants). The risk of all-cause mortality was not different between first-line beta-blockers and placebo (RR 0.99, 95%CI 0.88 to 1.11, I(2)=0%), diuretics or RAS inhibitors, but was higher for beta-blockers compared to CCBs (RR 1.07, 95%CI 1.00 to 1.14, I(2)=2.2%; ARI=0.5%, NNH=200). The risk of total cardiovascular disease (CVD) was lower for first-line beta-blockers compared to placebo (RR 0.88, 95%CI 0.79 to 0.97, I(2)=21.4%, ARR=0.7%, NNT=140). This is primarily a reflection of the significant decrease in stroke (RR 0.80, 95%CI 0.66 to 0.96; I(2)=0%; ARR=0.5%, NNT=200); coronary heart disease (CHD) risk was not significantly different between beta-blockers and placebo. The effect of beta-blockers on CVD was significantly worse than that of CCBs (RR 1.18, 95%CI 1.08 to 1.29, I(2)=0%; ARI=1.3%, NNH=80), but was not significantly different from that of diuretics or RAS inhibitors. Increased total CVD was due to an increase in stroke compared to CCBs (RR 1.24, 95%CI 1.11 to 1.40, I(2)=0%; ARI=0.6%, NNH=180). There was also an increase in stroke with beta-blockers as compared to RAS inhibitors (RR 1.30, 95%CI 1.11 to 1.53, I(2)=29.1%; ARI=1.5%, NNH=65). CHD was not significantly different between beta-blockers and diuretics or CCBs or RAS inhibitors. In addition, patients on beta-blockers were more likely to discontinue treatment due to side effects than those on diuretics (RR 1.86, 95%CI 1.39 to 2.50, I(2)=78.2%, ARI=6.4% NNH=16) and RAS inhibitors (RR 1.41, 95%CI 1.29 to 1.54, I(2)=12.1%; ARI=5.5%, NNH=18), but there was no significant difference with CCBs.

AUTHORS' CONCLUSIONS

The available evidence does not support the use of beta-blockers as first-line drugs in the treatment of hypertension. This conclusion is based on the relatively weak effect of beta-blockers to reduce stroke and the absence of an effect on coronary heart disease when compared to placebo or no treatment. More importantly, it is based on the trend towards worse outcomes in comparison with calcium-channel blockers, renin-angiotensin system inhibitors, and thiazide diuretics. Most of the evidence for these conclusions comes from trials where atenolol was the beta-blocker used (75% of beta-blocker participants in this review). However, it is not known at present whether beta-blockers have differential effects on younger and elderly patients or whether there are differences between the different sub-types of beta-blockers.

The epidemiology of stroke in sickle cell patients in Yaounde, Cameroon

BACKGROUND AND PURPOSE

Stroke, a severe and recurrent but preventable complication of sickle cell disease (SCD), has not been well studied in Cameroon. To obtain baseline data towards the development of a national stroke prevention programme in SCD, we studied a sample of sickle cell patients with the aim of determining stroke prevalence, clinical presentation and management practices.

PATIENTS AND METHODS

Homozygous sickle cell patients in two centres in Yaounde were screened for stroke, in a cross-sectional study. Stroke was diagnosed clinically and confirmed where possible with brain computerized tomography. The National Institutes of Health Stroke Score (NIHSS) and modified Rankin scale (mRS) were used to assess stroke severity. Management practices were noted from patient charts.

RESULTS

One hundred and twenty patients aged 7 months to 35 years (mean age 13.49+/-8.79 years) were included. Eight cases of stroke (mean age 16.6+/-11.2 years) were identified, giving a stroke prevalence of 6.67%. Cerebral infarction was thrice as common as cerebral hemorrhage and clinical presentation was classical. Cerebral infarction was more frequent in patients aged below 20 years and hemorrhage in those above 20 (p=0.11). The annual recurrence rate was 25%. Missed diagnosis rate by attending physician was 25%. The NIHSS and mRS showed high stroke severity. Stroke management practices were insufficient and no patient received any form of stroke prophylaxis.

CONCLUSION

Stroke prevalence and presentation in sickle cell patients in Yaounde is similar to that observed in developed countries, but the wide management gap calls for rapid action. Our situation is ideal for the study of the natural history of stroke in sickle cell disease.

Vaginal disinfection for preventing mother-to-child transmission of HIV infection

BACKGROUND

Mother-to-child transmission (MTCT) of HIV infection is one of the most tragic consequences of the HIV epidemic, especially in resource-limited countries, resulting in about 650 000 new paediatric HIV infections each year worldwide. The paediatric HIV epidemic threatens to seriously undermine decade-old child survival programmes.

OBJECTIVES

To estimate the effect of vaginal disinfection on the risk of MTCT of HIV and infant and maternal mortality and morbidity, as well as tolerability of vaginal disinfection in HIV-infected women.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register, Cochrane Pregnancy and Childbirth Register, PubMed, EMBASE, AIDSLINE, LILACS, AIDSTRIALS, and AIDSDRUGS, using standardised methodological filters for identifying trials. We also searched reference lists of identified articles, relevant editorials, expert opinions and letters to journal editors, and abstracts and proceedings of relevant conferences, and contacted subject experts and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Randomised trials or clinical trials comparing vaginal disinfection during labour with placebo or no treatment, in known HIV-infected pregnant women. Trials had to include an estimate of the effect of vaginal disinfection on MTCT of HIV and or infant and maternal mortality and morbidity.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trial eligibility and quality, and extracted data. Meta-analysis was performed using the Yusuf-Peto modification of Mantel-Haenszel's fixed effect method.

MAIN RESULTS

Only two trials that included 708 patients met the inclusion criteria. The effect of vaginal disinfection on the risk of MTCT of HIV (OR 0.93, 95% CI 0.65 to 1.33), neonatal death (OR 1.38, 95% CI 0.30 to 6.33), and death after the neonatal period (OR 1.45, 95% CI 0.47 to 4.45) is uncertain. There was no evidence that vaginal disinfection increased adverse effects in mothers (OR 1.15, 95% CI 0.41 to 3.22), and evidence from one trial showed that adverse effects decreased in neonates (OR 0.14, 95% CI 0.07 to 0.31).

AUTHORS' CONCLUSIONS

Currently, there is no evidence of an effect of vaginal disinfection on the risk of MTCT of HIV. Given its simplicity and low cost, there is need for a large well-designed and well-conducted randomised controlled trial to assess the additive effect of vaginal disinfection on the risk of MTCT of HIV in antiretroviral treated women.

Vitamin A supplementation for reducing the risk of mother-to-child transmission of HIV infection

BACKGROUND

Mother-to-child transmission (MTCT) of HIV is the dominant mode of acquisition of HIV infection for children, currently resulting in more than 2000 new paediatric HIV infections each day worldwide.

OBJECTIVES

To assess the effects of antenatal and intrapartum vitamin A supplementation on the risk of MTCT of HIV infection and infant and maternal mortality and morbidity, and the tolerability of vitamin A supplementation.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, AIDSLINE, LILACS, AIDSTRIALS, and AIDSDRUGS, using standardised methodological filters for identifying trials. We also searched reference lists of identified articles, relevant editorials, expert opinions and letters to journal editors, and abstracts or proceedings of relevant conferences; and contacted subject experts, agencies, organisations, academic centres, and pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Randomised trials comparing vitamin A supplementation with no vitamin A supplementation in known HIV infected pregnant women. Trials had to include an estimate of the effect of vitamin A supplementation on MTCT of HIV and or any other adverse pregnancy outcome to be included.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and quality and extracted data. Effect measures (odds ratio [OR] for binary variables and weighted mean difference [WMD] for continuous variables) with their 95% confidence intervals (CI) were estimated for each study and combined using the fixed effect (Mantel-Haenszel) method, by intention to treat. Heterogeneity between studies was examined by graphical inspection of results followed by a chi-square test of homogeneity.

MAIN RESULTS

Four trials, which enrolled 3,033 HIV-infected pregnant women, are included in this review. There was no evidence of an effect of vitamin A supplementation on MTCT of HIV infection (OR 1.14, 95% CI 0.93 to 1.38). There was evidence of heterogeneity between the three trials with information on MTCT of HIV (I(2) =75.7%, P=0.02). While the trials conducted in South Africa (OR 0.98, 95% CI 0.67 to 1.42 at three months) and Malawi (OR 0.78, 95% CI 0.53 to 1.15 at 24 months) did not find evidence that the effect of Vitamin A supplementation was different from that of placebo, the trial in Tanzania did find evidence that vitamin A supplementation increased the risk of MTCT of HIV (OR 1.53, 95% CI 1.15 to 2.04 at 24 months). Vitamin A supplementation significantly improved birth weight (WMD 89.78, 95% CI 84.73 to 94.83), but there was no evidence of an effect of vitamin A supplementation on stillbirths (OR 0.99, 95% CI 0.67 to 1.46), preterm births (OR 0.89, 95% CI 0.71 to 1.11), death by 24 months among live births (OR 1.11, 95% CI 0.88 to 1.40), postpartum CD4 levels (WMD -4.00, 95% CI -51.06 to 43.06), and maternal death (OR 0.49, 95%CI 0.04 to 5.40).

IMPLICATIONS FOR PRACTICE

Currently available evidence do not support the use of vitamin A supplementation of HIV-infected pregnant women to reduce MTCT of HIV, though there is an indication that vitamin A supplementation improves birth weight.

IMPLICATIONS FOR RESEARCH

The awaited publication of data from a large trial involving 4,495 HIV infected pregnant women in Harare (Zimbabwe Vitamin A for Mothers and Babies Project), will further clarify the effect of vitamin A supplementation on MTCT of HIV. The current review will be updated as soon as the trial is published.