Progress Toward Hepatitis B Control and Elimination of Mother-to-Child Transmission of Hepatitis B Virus - World Health Organization African Region, 2016-2021.

Chronic hepatitis B virus (HBV) infection is one of the leading causes of cirrhosis and liver cancer. In 2019, approximately 1.5 million persons newly acquired chronic HBV infection; among these, 990,000 (66%) were in the World Health Organization (WHO) African Region (AFR). Most chronic HBV infections are acquired through mother-to-child transmission (MTCT) or during early childhood, and approximately two thirds of these infections occur in AFR. In 2016, the World Health Assembly endorsed the goal of elimination of mother-to-child transmission (EMTCT) of HBV, documented by ≥90% coverage with both a timely hepatitis B vaccine (HepB) birth dose (HepB-BD) and 3 infant doses of HepB (HepB3), and ≤0.1% hepatitis B surface antigen (HBsAg) seroprevalence among children aged ≤5 years. In 2016, the WHO African Regional Committee endorsed targets for a 30% reduction in incidence (≤2% HBsAg seroprevalence in children aged ≤5 years) and ≥90% HepB3 coverage by 2020. By 2021, all 47 countries in the region provided HepB3 to infants beginning at age 6 weeks, and 14 countries (30%) provided HepB-BD. By December 2021, 16 (34%) countries achieved ≥90% HepB3 coverage, and only two (4%) achieved ≥90% timely HepB-BD coverage. Eight countries (17%) conducted nationwide serosurveys among children born after the introduction of HepB to assess HBsAg seroprevalence: six countries had achieved ≤2% seroprevalence, but none had achieved ≤0.1% seroprevalence among children. The development of immunization recovery plans following the COVID-19 pandemic provides an opportunity to accelerate progress toward hepatitis B control and EMTCT, including introducing HepB-BD and increasing coverage with timely HepB-BD and HepB3 vaccination. Representative HBsAg serosurveys among children and a regional verification body for EMTCT of HBV will be needed to monitor progress.

COVID-19 Vaccination in the WHO African Region: Progress Made in 2022 and Factors Associated.

This study summarizes progress made in rolling out COVID-19 vaccinations in the African region in 2022, and analyzes factors associated with vaccination coverage. Data on vaccine uptake reported to the World Health Organization (WHO) Regional Office for Africa by Member States between January 2021 and December 2022, as well as publicly available health and socio-economic data, were used. A negative binomial regression was performed to analyze factors associated with vaccination coverage in 2022. As of the end of 2022, 308.1 million people had completed the primary vaccination series, representing 26.4% of the region's population, compared to 6.3% at the end of 2021. The percentage of health workers with complete primary series was 40.9%. Having carried out at least one high volume mass vaccination campaign in 2022 was associated with high vaccination coverage (ß = 0.91, p < 0.0001), while higher WHO funding spent per person vaccinated in 2022 was correlated with lower vaccination coverage (ß = -0.26, p < 0.03). All countries should expand efforts to integrate COVID-19 vaccinations into routine immunization and primary health care, and increase investment in vaccine demand generation during the transition period that follows the acute phase of the pandemic.

Lessons Learned and Future Perspectives for Rotavirus Vaccines Switch in the World Health Organization, Regional Office for Africa.

BACKGROUND: Following the World Health Organization (WHO) recommendation, 38/47 countries have introduced rotavirus vaccines into the program of immunization in the WHO Regional Office for Africa (WHO/AFRO). Initially, two vaccines (Rotarix and Rotateq) were recommended and recently two additional vaccines (Rotavac and Rotasiil) have become available. However, the global supply challenges have increasingly forced some countries in Africa to switch vaccine products. Therefore, the recent WHO pre-qualified vaccines (Rotavac, Rotasiil) manufactured in India, offer alternatives and reduce global supply challenges related to rotavirus vaccines; Methods: Using a questionnaire, we administered to the Program Managers, Expanded Program for Immunization, we collected data on vaccine introduction and vaccine switch and the key drivers of the decisions for switching vaccines products, in the WHO/AFRO. Data was also collected fromliterature review and the global new vaccine introduction status data base maintained by WHO and other agencies. RESULTS: Of the 38 countries that introduced the vaccine, 35 (92%) initially adopted Rotateq or Rotarix; and 23% (8/35) switched between products after rotavirus vaccine introduction to either Rotavac (n = 3), Rotasiil (n = 2) or Rotarix (n = 3). Three countries (Benin, Democratic Republic of Congo and Nigeria) introduced the rotavirus vaccines manufactured in India. The decision to either introduce or switch to the Indian vaccines was predominately driven by global supply challenges or supply shortage. The withdrawal of Rotateq from the African market, or cost-saving for countries that graduated or in transition from Gavi support was another reason to switch the vaccine; Conclusions: The recently WHO pre-qualified vaccines have offered the countries, opportunities to adopt these cost-effective products, particularly for countries that have graduated or transitioning from full Gavi support, to sustain the demand of vaccines products.

Use of a rapid digital microfluidics-powered immunoassay for assessing measles and rubella infection and immunity in outbreak settings in the Democratic Republic of the Congo.

The Democratic Republic of the Congo (DRC) has a high measles incidence despite elimination efforts and has yet to introduce rubella vaccine. We evaluated the performance of a prototype rapid digital microfluidics powered (DMF) enzyme-linked immunoassay (ELISA) assessing measles and rubella infection, by testing for immunoglobulin M (IgM), and immunity from natural infection or vaccine, by testing immunoglobulin G (IgG), in outbreak settings. Field evaluations were conducted during September 2017, in Kinshasa province, DRC. Blood specimens were collected during an outbreak investigation of suspected measles cases and tested for measles and rubella IgM and IgG using the DMF-ELISA in the field. Simultaneously, a household serosurvey for measles and rubella IgG was conducted in a recently confirmed measles outbreak area. DMF-ELISA results were compared with reference ELISA results tested at DRC's National Public Health Laboratory and the US Centers for Disease Control and Prevention. Of 157 suspected measles cases, rubella IgM was detected in 54% while measles IgM was detected in 13%. Measles IgG-positive cases were higher among vaccinated persons (87%) than unvaccinated persons (72%). In the recent measles outbreak area, measles IgG seroprevalence was 93% overall, while rubella seroprevalence was lower for children (77%) than women (98%). Compared with reference ELISA, DMF-ELISA sensitivity and specificity were 82% and 78% for measles IgG; 88% and 89% for measles IgM; 85% and 85% for rubella IgG; and 81% and 83% for rubella IgM, respectively. Rubella infection was detected in more than half of persons meeting the suspected measles case definition during a presumed measles outbreak, suggesting substantial unrecognized rubella incidence, and highlighting the need for rubella vaccine introduction into the national schedule. The performance of the DMF-ELISA suggested that this technology can be used to develop rapid diagnostic tests for measles and rubella.

Progress with COVID-19 vaccination in the WHO African Region in 2021.

Introduction: as of end 2021, ten different vaccines have received Emergency use listing by the World Health Organisation. The vaccination response to the COVID pandemic started in February 2021 in the WHO African Region. WHO proposed a national coverage target of fully vaccinated population of 40% by the end of December 2021. This manuscript attempts to review the progress in the roll-out of COVID-19 vaccination in the African Region. Methods: we analysed the aggregate COVID-19 vaccine uptake and utilization data from the immunisation monitoring databases set up by countries and shared with the WHO Regional Office for Africa. Results: as of 31 December 2021, a total of 340,663,156 doses of COVID-19 vaccine were received in 46 countries in the African Region. The weekly average doses administered was 4,069,934 throughout the year. In the same period, a total of 114,498,980 persons received at least one dose, and 71,862,108 people were fully vaccinated, amounting to 6.6% of the total population in the Region. Only 5 countries attained the target of 40% full vaccination coverage. Disaggregated information was not available from all countries on the number of persons vaccinated by gender, and according to the priority population groupings. A total of 102,046 cases of adverse events following immunisation (AEFIs) were reported among which 6,260 (6.1%) were labelled as severe AEFIs. Conclusion: COVID-19 vaccination coverage remains very low in the African Region, with all but 5 countries missing the 40% coverage target as of December 2021. Countries, donors and partners should mobilise political will and resources towards the attainment of the coverage targets. Countries will need to implement vaccination efforts using tailored approaches to reach unreached populations. The reporting gaps indicate the need to invest on efforts to improve the capture, analysis and use of more granular program data.

Epidemiology and pre-vaccine burden of rotavirus diarrhea in Democratic Republic of Congo (DRC): Results of sentinel surveillance, 2009-2019.

INTRODUCTION: Since August 2009, the Democratic Republic of Congo (DRC) has implemented sentinel site surveillance for rotavirus gastroenteritis. Limited hospital studies have been carried out, in DRC, describing the epidemiology of rotavirus diarrhea before rotavirus vaccine introduction in October 2019. This analysis describes the epidemiology of rotavirus gastroenteritis and characteristics of circulating viral strains from 2009 to 2019. MATERIALS AND METHODS: We analyzed demographic and clinic data collected from children < 5 years old enrolled at three rotavirus sentinel surveillance sites in DRC during 2009-2019, prior to rotavirus vaccine introduction in 2019. Data have been described and presented as mean ± standard deviation for quantitative variables with normal distribution, or as median with an interquartile range [Q1-Q3] for quantitative variables with non-normal distribution, or as absolute value with percentage for qualitative variables. RESULTS: Between August 2009 and December 2019, 4,928 children < 5 years old were admitted to sentinel surveillance sites for gastroenteritis in the DRC; the rotavirus positivity rate was 60 %. There was a slight male gender predominance (56 %), and the majority of children (79 %) were 0-11 months of age. Every year, the incidence was highest between May and September corresponding to the dry and cool season. Genotyping was performed for 50 % of confirmed rotavirus cases. The most common G genotypes were G1 (39 %) and G2 (24 %) and most common P genotypes were P[6] (49 %) and P[8] (37 %). The most common G-P genotype combinations were G1P[8] (22 %), G2P[6] (16 %) and G1P[6] (14 %). Genotype distribution varied by site, age group, and year. CONCLUSION: From 2009 to 2019, rotavirus-associated gastroenteritis represented a significant burden among DRC children under 5 who were admitted to sentinel sites. G1P[8] was the most commonly identified genotype. Continued monitoring after the introduction of rotavirus vaccine will be essential to monitor any changes in epidemiology.

Immunisation program training needs in 9 countries in the African Region.

INTRODUCTION: regular in-service training of healthcare workers within the immunization program is critical to address the program needs created by the introduction of new vaccines and technologies, as well as the expanding scope of immunisation programmes beyond infant immunization and towards a life-course approach. National immunization programs conduct in-service training of health workers depending on program needs and particularly when new program elements are introduced. METHODS: we conducted a survey of national and provincial level immunization program staff in 9 countries in the World Health Organization (WHO) African Region to determine the perceived needs and preferred training methods for capacity building in immunisation. RESULTS: nearly all of the respondents (98.3%) stated that there are skill gaps at their respective levels in the immunization program which require training, with 88% indicating that mid-level program management (MLM) training was needed to train new program staff, while 78% indicated program performance gaps and 60% of the respondents stated that refresher training is needed. Program areas identified as top priorities for training included immunisation monitoring and data quality, sustainable immunization financing, adverse events monitoring and community mobilization. More than three quarters of the respondents (78%) think that online MLM training is adequate to address program gaps. Only four of the 9 immunization program managers indicated that they regularly monitor the number of MLM trained staff within their national program. CONCLUSION: there is a strong need for in-service training of immunization program officers in the countries surveyed, especially at the subnational levels. Program managers should conduct regular monitoring of the training status of staff, as well as conduct detailed training needs assessments in order to tailor the training approaches and topics. Online training provides an acceptable approach for capacity building of immunization program staff.

Impact of Rotavirus Vaccine Introduction on Rotavirus Hospitalizations Among Children Under 5 Years of Age-World Health Organization African Region, 2008-2018.

BACKGROUND: Rotavirus is the leading cause of acute gastroenteritis (AGE) among children worldwide. Prior to rotavirus vaccine introduction, over one third of AGE hospitalizations in Africa were due to rotavirus. We describe the impact of rotavirus vaccines using data from the African Rotavirus Surveillance Network (ARSN). METHODS: For descriptive analysis, we included all sites reporting to ARSN for any length of time between 2008 and 2018. For vaccine impact analysis, continuous surveillance throughout the year was required to minimize potential bias due to enrollment of partial seasons and sites had to report a minimum of 100 AGE cases per year. We report the proportion of rotavirus AGE cases by year relative to vaccine introduction, and the relative reduction in the proportion of rotavirus AGE cases reported following vaccine introduction. RESULTS: From 2008 to 2018, 97 366 prospectively enrolled hospitalized children <5 years of age met the case definition for AGE, and 34.1% tested positive for rotavirus. Among countries that had introduced rotavirus vaccine, the proportion of hospitalized AGE cases positive for rotavirus declined from 39.2% in the prevaccine period to 25.3% in the postvaccine period, a 35.5% (95% confidence interval [CI]: 33.7-37.3) decline. No declines were observed among countries that had not introduced the vaccine over the 11-year period. CONCLUSIONS: Rotavirus vaccine introduction led to large and consistent declines in the proportion of hospitalized AGE cases that are positive for rotavirus. To maximize the public health benefit of these vaccines, efforts to introduce rotavirus vaccines in the remaining countries in the region and to improve coverage should continue.

Implementation of the World Health Organization recommendation on the use of rotavirus vaccine without age restriction by African countries.

The World Health Organization (WHO) recommended the worldwide use of rotavirus vaccines initially in 2007 and 2009 applying a strict age restriction criterion due to the potential for age-related association with increased risk of intussusception in infants. The restriction was relaxed in the 2013 after detailed review of robust safety data generated in post-marketing surveillance studies. We assessed the status of the implementation of the 2013 recommendation to remove age restriction in the WHO African region (AFR). Of the approximately 75% (35/47) of countries that had introduced the vaccine by 2018, only 43% (15/35) removed age restriction, exclusively from South and East sub-region (78%, 14/18). Avoiding confusion at the health facilities and financial constraints particularly resources required for re-training the health workers, use of vaccine off-label were cited as the main reasons for not implementing the 2013 WHO recommendation on age restriction removal. The 2013 WHO recommendation has not been fully implemented by African countries, suggesting the need for technical advisory bodies to further guide the countries, continue monitoring the implementation status and impact on the rotavirus vaccine coverage and intussusception in the Africa region.

Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report.

BACKGROUND: In 2016, the response to a yellow fever outbreak in Angola and the Democratic Republic of Congo led to a global shortage of yellow fever vaccine. As a result, a fractional dose of the 17DD yellow fever vaccine (containing one fifth [0.1 ml] of the standard dose) was offered to 7.6 million children 2 years of age or older and nonpregnant adults in a preemptive campaign in Kinshasa. The goal of this study was to assess the immune response to the fractional dose in a large-scale campaign. METHODS: We recruited participants in four age strata at six vaccination sites. We assessed neutralizing antibody titers against yellow fever virus in blood samples obtained before vaccination and at 1 month and 1 year after vaccination, using a plaque reduction neutralization test with a 50% cutoff (PRNT50). Participants with a PRNT50 titer of 10 or higher were considered to be seropositive. Those with a baseline titer of less than 10 who became seropositive at follow-up were classified as having undergone seroconversion. Participants who were seropositive at baseline and who had an increase in the titer by a factor of 4 or more at follow-up were classified as having an immune response. RESULTS: Among 716 participants who completed the 1-month follow-up, 705 (98%; 95% confidence interval [CI], 97 to 99) were seropositive after vaccination. Among 493 participants who were seronegative at baseline, 482 (98%; 95% CI, 96 to 99) underwent seroconversion. Among 223 participants who were seropositive at baseline, 148 (66%; 95% CI, 60 to 72) had an immune response. Lower baseline titers were associated with a higher probability of having an immune response (P<0.001). Among 684 participants who completed the 1-year follow-up, 666 (97%; 95% CI, 96 to 98) were seropositive for yellow fever antibody. The distribution of titers among the participants who were seronegative for yellow fever antibody at baseline varied significantly among age groups at 1 month and at 1 year (P<0.001 for both comparisons). CONCLUSIONS: A fractional dose of the 17DD yellow fever vaccine was effective at inducing seroconversion in participants who were seronegative at baseline. Titers remained above the threshold for seropositivity at 1 year after vaccination in nearly all participants who were seropositive at 1 month after vaccination. These findings support the use of fractional-dose vaccination for outbreak control. (Funded by the U.S. Agency for International Development and the Centers for Disease Control and Prevention.).

Expansion of Vaccination Services and Strengthening Vaccine-Preventable Diseases Surveillance in Haiti, 2010-2016.

Following the 2010 earthquake, Haiti was at heightened risk for vaccine-preventable diseases (VPDs) outbreaks due to the exacerbation of long-standing gaps in the vaccination program and subsequent risk of VPD importation from other countries. Therefore, partners supported the Haitian Ministry of Health and Population to improve vaccination services and VPD surveillance. During 2010-2016, three polio, measles, and rubella vaccination campaigns were implemented, achieving a coverage > 90% among children and maintaining Haiti free of those VPDs. Furthermore, Haiti is on course to eliminate maternal and neonatal tetanus, with 70% of communes achieving tetanus vaccine two-dose coverage > 80% among women of childbearing age. In addition, the vaccine cold chain storage capacity increased by 91% at the central level and 285% at the department level, enabling the introduction of three new vaccines (pentavalent, rotavirus, and pneumococcal conjugate vaccines) that could prevent an estimated 5,227 deaths annually. Haiti moved from the fourth worst performing country in the Americas in 2012 to the sixth best performing country in 2015 for adequate investigation of suspected measles/rubella cases. Sentinel surveillance sites for rotavirus diarrhea and meningococcal meningitis were established to estimate baseline rates of those diseases prior to vaccine introduction and to evaluate the impact of vaccination in the future. In conclusion, Haiti significantly improved vaccination services and VPD surveillance. However, high dependence on external funding and competing vaccination program priorities are potential threats to sustaining the improvements achieved thus far. Political commitment and favorable economic and legal environments are needed to maintain these gains.

Seroprevalence of measles and rubella antibodies in pregnant women Haiti, 2012.

BACKGROUND: Haiti had set a national goal to eliminate measles and rubella, as well as congenital rubella syndrome (CRS) by 2010. A 2007-2008 nationwide measles and rubella vaccination campaign targeting 1-19 years, however, reached only 79% of the target population. To assess whether population immunity was adequate to support elimination, we conducted a national serosurvey. METHODS: We systematically selected 740 serum specimens collected from pregnant women in a 2012 national antenatal HIV sentinel serosurvey across four age strata: 15-19, 20-24, 25-29 and 30-39 years. Sera were tested for measles and rubella specific immunoglobulin G antibodies (IgG) using commercial immunoassays. We classified sera as seropositive, seronegative or indeterminate per manufacturer's instructions, and analyzed seroprevalence according to age strata, and rural or urban residence. We assessed immunity by estimating antibody concentrations in international units per milliliter (IU/mL) for seropositive and indeterminate sera. Measles IgG concentrations >0.12 IU/mL and rubella IgG concentrations >10 IU/mL were considered clinically protective. RESULTS: Of 740 sera, 696 (94.1%) were seropositive and 20 (2.7%) were indeterminate for measles IgG; overall 716 (96.8%) sera had IgG concentrations >0.12 IU/mL. For rubella IgG, 691 (93.4%) sera were seropositive and 1 (0.1%) was indeterminate; a total of 687 (92.8%) had IgG concentrations >10 IU/mL. Measles seropositivity varied across age strata (p=0.003); seropositivity increased from 88.6% among 15-19 year olds to 98.4% among 30-39 year olds (Cochran-Armitage trend tes t ≤ 0.0001). Rubella seropositivity did not differ across age strata. There were no statistically significant differences in measles or rubella seropositivity by urban versus rural residence. CONCLUSION: Despite previous low vaccination coverage for measles, results from this serosurvey indicate high levels of measles and rubella seropositivity in pregnant women, and contribute to the evidence for measles, rubella and CRS elimination from Haiti by the target date.