Progress Toward Measles Elimination - World Health Organization Eastern Mediterranean Region, 2019-2022

In 2015, all 22 World Health Organization Eastern Mediterranean Region (EMR) countries and areas (countries) pledged to achieve measles elimination by 2020. Despite success in several countries, most countries in the region still have not eliminated measles. This report updates a previous report and describes progress toward measles elimination in EMR during 2019-2022. During that period, estimated regional coverage with the first and second doses of a measles-containing vaccine (MCV) was 82%-83% and 76%-78%, respectively. During 2019-2022, approximately 160 million children were vaccinated during national or subnational supplementary immunization activities. Reported confirmed regional measles incidence decreased from 29.8 cases per 1 million population in 2019 to 7.4 in 2020, but then increased 68%, to 50.0 in 2022 because of challenges providing immunization services and conducting surveillance during the COVID-19 pandemic. Surveillance indicators deteriorated in 11 (50%) of the 22 EMR countries. During 2019-2022, four countries in the region were verified as having achieved measles elimination, but other countries reported immunity gaps and increased measles incidence in 2022. To achieve measles elimination in EMR, national immunization programs, especially in those countries with high measles incidence, will need to continue to recover from the COVID-19 pandemic, increase overall vaccination coverage to close immunity gaps, and maintain high-quality disease surveillance.

Rotavirus genotypes in children under five years hospitalized with diarrhea in low and middle-income countries: Results from the WHO-coordinated Global Rotavirus Surveillance Network

Rotavirus is the most common pathogen causing pediatric diarrhea and an important cause of morbidity and mortality in low- and middle-income countries. Previous evidence suggests that the introduction of rotavirus vaccines in national immunization schedules resulted in dramatic declines in disease burden but may also be changing the rotavirus genetic landscape and driving the emergence of new genotypes. We report genotype data of more than 16,000 rotavirus isolates from 40 countries participating in the Global Rotavirus Surveillance Network. Data from a convenience sample of children under five years of age hospitalized with acute watery diarrhea who tested positive for rotavirus were included. Country results were weighted by their estimated rotavirus disease burden to estimate regional genotype distributions. Globally, the most frequent genotypes identified after weighting were G1P[8] (31%), G1P[6] (8%) and G3P[8] (8%). Genotypes varied across WHO Regions and between countries that had and had not introduced rotavirus vaccine. G1P[8] was less frequent among African (36 vs 20%) and European (33 vs 8%) countries that had introduced rotavirus vaccines as compared to countries that had not introduced. Our results describe differences in the distribution of the most common rotavirus genotypes in children with diarrhea in low- and middle-income countries. G1P[8] was less frequent in countries that had introduced the rotavirus vaccine while different strains are emerging or re-emerging in different regions.

Evaluation of the World Health Organization Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network's Laboratory External Quality Assessment Programme, 2014-2019

Introduction. In 2009, the World Health Organization (WHO) established the Global Invasive Bacterial Vaccine Preventable Disease (IB-VPD) Surveillance Network (GISN) to monitor the global burden and aetiology of bacterial meningitis, pneumonia and sepsis caused by Haemophilus influenzae (Hi), Neisseria meningitidis (Nm) and Streptococcus pneumoniae (Sp).Hypothesis/Gap Statement. The GISN established an external quality assessment (EQA) programme for the characterization of Hi, Nm and Sp by culture and diagnostic PCR.Aim. To assess the performance of sentinel site laboratories (SSLs), national laboratories (NLs) and regional reference laboratories (RRLs) between 2014 and 2019 in the EQA programme.Methodology. Test samples consisted of bacterial smears for Gram-staining, viable isolates for identification and serotyping or serogrouping (ST/SG), plus simulated cerebrospinal fluid (CSF) samples for species detection and ST/SG by PCR. SSLs and NLs were only required to analyse the slides for Gram staining and identify the species of the live isolates. RRLs, and any SLs and NLs that had the additional laboratory capacity, were also required to ST/SG the viable isolates and analyse the simulated CSF samples.Results. Across the period, 69-112 SS/NL labs and eight or nine RRLs participated in the EQA exercise. Most participants correctly identified Nm and Sp in Gram-stained smears but were less successful with Hi and other species. SSLs/NLs identified the Hi, Nm and Sp cultures well and also submitted up to 56 % of Hi, 62 % of Nm and 33 % of Sp optional ST/SG results each year. There was an increasing trend in the proportion of correct results submitted over the 6 years for Nm and Sp. Some SSLs/NLs also performed the optional detection and ST/SG of the three organisms by PCR in simulated CSF from 2015 onwards; 89-100 % of the CSF samples were correctly identified and 76-93 % of Hi-, 90-100 % of Nm- and 75-100 % of Sp-positive samples were also correctly ST/SG across the distributions. The RRLs performed all parts of the EQA to a very high standard, with very few errors across all aspects of the EQA.Conclusion. The EQA has been an important tool in maintaining high standards of laboratory testing and building of laboratory capacity in the GISN.

External quality assessment of laboratory performance in bacteriology in the Eastern Mediterranean Region, 2011-2019

Background

Since 2007, national public health laboratories in the WHO Eastern Mediterranean Region (EMR) have participated in a regional external quality assessment scheme in bacteriology to improve testing proficiency.

Aims

To assess laboratory performance in bacteriology in the EMR between 2011 and 2019 using the regional external quality assessment scheme.

Methods

We analysed the accuracy of participant-reported data in bacterial identification, Gram stain microscopy, and antimicrobial susceptibility testing. For each category, we assessed the performance over time, the performance on multiple organisms, and whether a laboratory repeatedly failed to attain satisfactory results.

Results

Between 2011 and 2019, 70% of laboratories achieved satisfactory performance for bacterial identification and antimicrobial susceptibility testing, and 85% performed satisfactory Gram stain microscopy. Testing did not improve on multiple organisms and results were consistently low for some pathogens and test categories. Twenty-nine percent of laboratories underperformed throughout the study period.

Conclusion

The unchanged performance over time and underperformance of laboratories highlight the need for improvements in the regional external quality assessment scheme. Participating laboratories and WHO need to work more actively to strengthen the problem areas.

Risk Factors for Mortality Among Children Younger Than Age 5 Years With Severe Diarrhea in Low- and Middle-income Countries: Findings From the World Health Organization-coordinated Global Rotavirus and Pediatric Diarrhea Surveillance Networks

BACKGROUND

Diarrhea is the second leading cause of death in children younger than 5 years of age globally. The burden of diarrheal mortality is concentrated in low-resource settings. Little is known about the risk factors for childhood death from diarrheal disease in low- and middle-income countries.

METHODS

Data from the World Health Organization (WHO)-coordinated Global Rotavirus and Pediatric Diarrhea Surveillance Networks, which are composed of active, sentinel, hospital-based surveillance sites, were analyzed to assess mortality in children <5 years of age who were hospitalized with diarrhea between 2008 and 2018. Case fatality risks were calculated, and multivariable logistic regression was performed to identify risk factors for mortality.

RESULTS

This analysis comprises 234 781 cases, including 1219 deaths, across 57 countries. The overall case fatality risk was found to be 0.5%. Risk factors for death in the multivariable analysis included younger age (for <6 months compared with older ages, odds ratio [OR] = 3.54; 95% confidence interval [CI], 2.81-4.50), female sex (OR = 1.18; 95% CI, 1.06-1.81), presenting with persistent diarrhea (OR = 1.91; 95% CI, 1.01-3.25), no vomiting (OR = 1.13; 95% CI, .98-1.30), severe dehydration (OR = 3.79; 95% CI, 3.01-4.83), and being negative for rotavirus on an enzyme-linked immunosorbent assay test (OR = 2.29; 95% CI, 1.92-2.74). Cases from the African Region had the highest odds of death compared with other WHO regions (OR = 130.62 comparing the African Region with the European Region; 95% CI, 55.72-422.73), whereas cases from the European Region had the lowest odds of death.

CONCLUSIONS

Our findings support known risk factors for childhood diarrheal mortality and highlight the need for interventions to address dehydration and rotavirus-negative diarrheal infections.

Inequities in the deployment of COVID-19 vaccine in the WHO Eastern Mediterranean Region, 2020-2021

The WHO Eastern Mediterranean Region (EMR) is characterised by a large range in routine immunisation coverage. We reviewed progress in access, deployment efforts, and use of COVID-19 vaccines in the EMR to identify bottlenecks and propose recommendations. We compiled and analysed data reported to WHO regarding the number of vaccines provided emergency use authorisation (EUA) in each country, the number of vaccine doses allocated and delivered by COVAX, the number of vaccine doses received bilaterally, the date of initiation of vaccination, vaccine usage rate and overall vaccination coverage. In June-July and October-November 2021, we conducted two rounds of a regional survey to assess vaccine acceptance and calculated the weighted proportion of individuals who would get vaccinated once a vaccine is available and recommended. We stratified the analysis according to four groups based on their participation status in COVAX, from the highest to lowest income, that is, (1) fully self-financing high-income countries (group 1), (2) fully self-financing upper middle-income countries (group 2), (3) Advance Market Commitment (AMC) countries not eligible to receive Gavi support (group 3) and (4) AMC countries eligible for Gavi support (group 4). As of 31 December 2021, the median number of vaccines provided with EUA was 6 for group 1, 11 for group 2, 8 for group 3 and 9 for group 4. On the same date, COVAX had delivered 179 793 310 doses to EMR countries. Vaccination started on 10 December 2020 in group 1, on 13 December 2020 in group 2, on 30 December 2020 in group 3 and on 20 January 2021 in group 4. The regional acceptance survey (first round) pointed to higher vaccine acceptance in group 1 (96%), than in others, including group 2 (73.9%), group 3 (78.8%) and group 4 (79.3%), with identical patterns in the second round (98%, 78%, 84% and 76%), respectively. Usage of vaccine allocated by COVAX to participating countries was 89% in group 1, 75% in group 2, 78% in group 3 and 42% in group 4. The full dose and partial dose coverage decreased with the income groups of countries, from 70% and 6% in group 1, to 43% and 8% in group 2, to 33% and 11% in group 3, and 20% and 8% in group 4. All 22 EMR countries introduced COVID-19 vaccines by 21 April 2021, but with major inequities in coverage. Additional efforts are needed to address the determinants of unequal vaccine coverage at all stages of the result chain to improve vaccine equity.

The Global Landscape of Pediatric Bacterial Meningitis Data Reported to the World Health Organization-Coordinated Invasive Bacterial Vaccine-Preventable Disease Surveillance Network, 2014-2019

BACKGROUND

The World Health Organization (WHO) coordinates the Global Invasive Bacterial Vaccine-Preventable Diseases (IB-VPD) Surveillance Network to support vaccine introduction decisions and use. The network was established to strengthen surveillance and laboratory confirmation of meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis.

METHODS

Sentinel hospitals report cases of children <5 years of age hospitalized for suspected meningitis. Laboratories report confirmatory testing results and strain characterization tested by polymerase chain reaction. In 2019, the network included 123 laboratories that follow validated, standardized testing and reporting strategies.

RESULTS

From 2014 through 2019, >137 000 suspected meningitis cases were reported by 58 participating countries, with 44.6% (n = 61 386) reported from countries in the WHO African Region. More than half (56.6%, n = 77 873) were among children <1 year of age, and 4.0% (n = 4010) died among those with reported disease outcome. Among suspected meningitis cases, 8.6% (n = 11 798) were classified as probable bacterial meningitis. One of 3 bacterial pathogens was identified in 30.3% (n = 3576) of these cases, namely S. pneumoniae (n = 2177 [60.9%]), H. influenzae (n = 633 [17.7%]), and N. meningitidis (n = 766 [21.4%]). Among confirmed bacterial meningitis cases with outcome reported, 11.0% died; case fatality ratio varied by pathogen (S. pneumoniae, 12.2%; H. influenzae, 6.1%; N. meningitidis, 11.0%). Among the 277 children who died with confirmed bacterial meningitis, 189 (68.2%) had confirmed S. pneumoniae. The proportion of pneumococcal cases with pneumococcal conjugate vaccine (PCV) serotypes decreased as the number of countries implementing PCV increased, from 77.8% (n = 273) to 47.5% (n = 248). Of 397 H. influenzae specimens serotyped, 49.1% (n = 195) were type b. Predominant N. meningitidis serogroups varied by region.

CONCLUSIONS

This multitier, global surveillance network has supported countries in detecting and serotyping the 3 principal invasive bacterial pathogens that cause pediatric meningitis. Streptococcus pneumoniae was the most common bacterial pathogen detected globally despite the growing number of countries that have nationally introduced PCV. The large proportions of deaths due to S. pneumoniae reflect the high proportion of meningitis cases caused by this pathogen. This global network demonstrated a strong correlation between PCV introduction status and reduction in the proportion of pneumococcal meningitis infections caused by vaccine serotypes. Maintaining case-based, active surveillance with laboratory confirmation for prioritized vaccine-preventable diseases remains a critical component of the global agenda in public health.The World Health Organization (WHO)-coordinated Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network reported data from 2014 to 2019, contributing to the estimates of the disease burden and serotypes of pediatric meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.