Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-9 (of 9 Records) |
Query Trace: Walldorf JA[original query] |
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Status of new vaccine introduction - worldwide, 2016-2021
Kaur G , Casey RM , Patel JC , Bloem P , Walldorf JA , Hyde TB . MMWR Morb Mortal Wkly Rep 2023 72 (27) 746-750 This report describes the status of introductions globally for eight World Health Organization (WHO)-recommended new and underutilized vaccines, comprising 10 individual vaccine antigens. By 2021, among 194 countries worldwide, 33 (17%) provided all of these 10 WHO-recommended antigens as part of their routine immunization schedules; only one low-income country had introduced all of these recommended vaccines. Universal hepatitis B birth dose; human papillomavirus vaccine; rotavirus vaccine; and diphtheria, tetanus, and pertussis-containing vaccine first booster dose have been introduced by 57%, 59%, 60%, and 72% of all countries worldwide, respectively. Pneumococcal conjugate vaccine, rubella-containing vaccine, measles-containing vaccine second dose, and Haemophilus influenzae type b vaccine have been introduced by 78%, 89%, 94%, and 99% of all countries, respectively. The annual rate of new vaccine introductions declined precipitously when the COVID-19 pandemic started, from 48 in 2019 to 15 in 2020 before rising to 26 in 2021. Increased efforts to accelerate new and underutilized vaccine introductions are urgently needed to improve universal equitable access to all recommended vaccines to achieve the global Immunization Agenda 2021-2030 (IA2030) targets. |
Vaccination information, motivations, and barriers in the context of meningococcal serogroup A conjugate vaccine introduction: A qualitative assessment among caregivers in Burkina Faso, 2018
Aksnes BN , Walldorf JA , Nkwenkeu SF , Zoma RL , Mirza I , Tarbangdo F , Fall S , Hien S , Ky C , Kambou L , Diallo AO , Aké FH , Hatcher C , Patel JC , Novak RT , Hyde TB , Medah I , Soeters HM , Jalloh MF . Vaccine 2021 39 (43) 6370-6377 BACKGROUND: In March 2017, Burkina Faso introduced meningococcal serogroup A conjugate vaccine (MACV) into the Expanded Programme on Immunization. MACV is administered to children aged 15-18 months, concomitantly with the second dose of measles-containing vaccine (MCV2). One year after MACV introduction, we assessed the sources and content of immunization information available to caregivers and explored motivations and barriers that influence their decision to seek MACV for their children. METHODS: Twenty-four focus group discussions (FGDs) were conducted with caregivers of children eligible for MACV and MCV2. Data collection occurred in February-March 2018 in four purposively selected districts, each from a separate geographic region; within each district, caregivers were stratified into groups based on whether their children were unvaccinated or vaccinated with MACV. FGDs were recorded and transcribed. Transcripts were coded and analyzed using qualitative content analysis. RESULTS: We identified many different sources and content of information about MACV and MCV2 available to caregivers. Healthcare workers were most commonly cited as the main sources of information; caregivers also received information from other caregivers in the community. Caregivers' motivations to seek MACV for their children were driven by personal awareness, engagements with trusted messengers, and perceived protective benefits of MACV against meningitis. Barriers to MACV and MCV2 uptake were linked to the unavailability of vaccines, immunization personnel not providing doses, knowledge gaps about the 15-18 month visit, practical constraints, past negative experiences, sociocultural influences, and misinformation, including misunderstanding about the need for MCV2. CONCLUSIONS: MACV and MCV2 uptake may be enhanced by addressing vaccination barriers and effectively communicating vaccination information and benefits through trusted messengers such as healthcare workers and other caregivers in the community. Educating healthcare workers to avoid withholding vaccines, likely due to fear of wastage, may help reduce missed opportunities for vaccination. |
Global rotavirus and pneumococcal conjugate vaccine introductions and the association with country disease surveillance, 2006-2018
Peck ME , Hampton LM , Antoni S , Ogbuanu I , Serhan F , Nakamura T , Walldorf JA , Cohen AL . J Infect Dis 2021 224 S184-s193 BACKGROUND: To inform the introduction of pneumococcal conjugate vaccine (PCV) and rotavirus vaccine, the World Health Organization (WHO) established the Global Invasive Bacterial Vaccine-Preventable Disease Surveillance Network (GISN) and the Global Rotavirus Surveillance Network (GRSN) in 2008. We investigated whether participation in these networks or other surveillance was associated with vaccine introduction. METHODS: Between 2006 and 2018, among all WHO member states, we used multivariable models adjusting for economic status to assess (1) the association between surveillance for pneumococcal disease or rotavirus disease, including participation in GISN or GRSN and the introduction of the PCV or the rotavirus vaccine, respectively, and (2) the association between the rotavirus disease burden and the rotavirus vaccine introduction among 56 countries participating in GRSN from 2008 to 2018. RESULTS: Countries that participated in or conducted surveillance for invasive pneumococcal disease or rotavirus disease were 3.5 (95% confidence interval [CI], 1.7-7.1) and 4.2 (95% CI, 2.1-8.6) times more likely to introduce PCV or rotavirus respectively, compared to those without surveillance. Among countries participating in GRSN, there was insufficient evidence to demonstrate an association between countries with higher rotavirus positivity and vaccine introduction. CONCLUSIONS: Surveillance should be incorporated into advocacy strategies to encourage the introduction of vaccines, with countries benefiting from data from, support for, and coordination of international disease surveillance networks. |
Health workers' perceptions and challenges in implementing meningococcal serogroup a conjugate vaccine in the routine childhood immunization schedule in Burkina Faso
Nkwenkeu SF , Jalloh MF , Walldorf JA , Zoma RL , Tarbangdo F , Fall S , Hien S , Combassere R , Ky C , Kambou L , Diallo AO , Krishnaswamy A , Ake FH , Hatcher C , Patel JC , Medah I , Novak RT , Hyde TB , Soeters HM , Mirza I . BMC Public Health 2020 20 (1) 254 BACKGROUND: Meningococcal serogroup A conjugate vaccine (MACV) was introduced in 2017 into the routine childhood immunization schedule (at 15-18 months of age) in Burkina Faso to help reduce meningococcal meningitis burden. MACV was scheduled to be co-administered with the second dose of measles-containing vaccine (MCV2), a vaccine already in the national schedule. One year following the introduction of MACV, an assessment was conducted to qualitatively examine health workers' perceptions of MACV introduction, identify barriers to uptake, and explore opportunities to improve coverage. METHODS: Twelve in-depth interviews were conducted with different cadres of health workers in four purposively selected districts in Burkina Faso. Districts were selected to include urban and rural areas as well as high and low MCV2 coverage areas. Respondents included health workers at the following levels: regional health managers (n = 4), district health managers (n = 4), and frontline healthcare providers (n = 4). All interviews were recorded, transcribed, and thematically analyzed using qualitative content analysis. RESULTS: Four themes emerged around supply and health systems barriers, demand-related barriers, specific challenges related to MACV and MCV2 co-administration, and motivations and efforts to improve vaccination coverage. Supply and health systems barriers included aging cold chain equipment, staff shortages, overworked and poorly trained staff, insufficient supplies and financial resources, and challenges with implementing community outreach activities. Health workers largely viewed MACV introduction as a source of motivation for caregivers to bring their children for the 15- to 18-month visit. However, they also pointed to demand barriers, including cultural practices that sometimes discourage vaccination, misconceptions about vaccines, and religious beliefs. Challenges in co-administering MACV and MCV2 were mainly related to reluctance among health workers to open multi-dose vials unless enough children were present to avoid wastage. CONCLUSIONS: To improve effective administration of vaccines in the second-year of life, adequate operational and programmatic planning, training, communication, and monitoring are necessary. Moreover, clear policy communication is needed to help ensure that health workers do not refrain from opening multi-dose vials for small numbers of children. |
Evaluation of the impact of meningococcal serogroup A conjugate vaccine introduction on second-year-of-life vaccination coverage in Burkina Faso
Zoma RL , Walldorf JA , Tarbangdo F , Patel JC , Diallo AO , Nkwenkeu SF , Kambou L , Nikiema M , Ouedraogo A , Bationo AB , Ouili R , Badolo H , Sawadogo G , Krishnaswamy A , Hatcher C , Hyde TB , Ake F , Novak RT , Wannemuehler K , Mirza I , Medah I , Soeters HM . J Infect Dis 2019 220 S233-s243 BACKGROUND: After successful meningococcal serogroup A conjugate vaccine (MACV) campaigns since 2010, Burkina Faso introduced MACV in March 2017 into the routine Expanded Programme for Immunization schedule at age 15-18 months, concomitantly with second-dose measles-containing vaccine (MCV2). We examined MCV2 coverage in pre- and post-MACV introduction cohorts to describe observed changes regionally and nationally. METHODS: A nationwide household cluster survey of children 18-41 months of age was conducted 1 year after MACV introduction. Coverage was assessed by verification of vaccination cards or recall. Two age groups were included to compare MCV2 coverage pre-MACV introduction (30-41 months) versus post-MACV introduction (18-26 months). RESULTS: In total, 15 925 households were surveyed; 7796 children were enrolled, including 3684 30-41 months of age and 3091 18-26 months of age. Vaccination documentation was observed for 86% of children. The MACV routine coverage was 58% (95% confidence interval [CI], 56%-61%) with variation by region (41%-76%). The MCV2 coverage was 62% (95% CI, 59%-65%) pre-MACV introduction and 67% (95% CI, 64%-69%) post-MACV introduction, an increase of 4.5% (95% CI, 1.3%-7.7%). Among children who received routine MACV and MCV2, 93% (95% CI, 91%-94%) received both at the same visit. Lack of caregiver awareness about the 15- to 18-month visit and vaccine unavailability were common reported barriers to vaccination. CONCLUSIONS: A small yet significant increase in national MCV2 coverage was observed 1 year post-MACV introduction. The MACV/MCV2 coadministration was common. Findings will help inform strategies to strengthen second-year-of-life immunization coverage, including to address the communication and vaccine availability barriers identified. |
Impact of 13-Valent Pneumococcal Conjugate Vaccine on Colonisation and Invasive Disease in Cambodian Children
Turner P , Leab P , Ly S , Sao S , Miliya T , Heffelfinger JD , Batmunkh N , Lessa FC , Walldorf JA , Hyde TB , Ork V , Hossain MS , Gould KA , Hinds J , Cooper BS , Ngoun C , Turner C , Day NPJ . Clin Infect Dis 2019 70 (8) 1580-1588 BACKGROUND: Cambodia introduced the 13-valent pneumococcal conjugate vaccine (PCV13) in January 2015 using a 3+0 dosing schedule and no catch-up campaign. We investigated the effects of this introduction on pneumococcal colonisation and invasive disease in children aged <5 years. METHODS: Six colonisation surveys were done between January 2014 and January 2018 in children attending the outpatient department of a non-governmental paediatric hospital in Siem Reap. Nasopharyngeal swabs were analysed by phenotypic and genotypic methods to detect pneumococcal serotypes and antimicrobial resistance. Invasive pneumococcal disease (IPD) data for January 2012 - December 2018 were retrieved from hospital databases. Pre-PCV IPD data and pre-/post-PCV colonisation data were modelled to estimate vaccine effectiveness (VE). RESULTS: Comparing 2014 with 2016-2018, and using adjusted prevalence ratios, vaccine effectiveness (VE) estimates for colonisation were 16.6% (95% CI 10.6-21.8) for all pneumococci and 39.2% (26.7-46.1) for vaccine serotype (VT) pneumococci. There was a 26.0% (17.7-33.0) decrease in multi-drug resistant pneumococcal colonisation. IPD incidence was estimated to have declined by 26.4% (14.4-35.8) by 2018, with a decrease of 36.3% (23.8-46.9) for VT IPD and an increase of 101.4% (62.0-145.4) for non-vaccine serotype IPD. CONCLUSIONS: Following PCV13 introduction into the Cambodian immunisation schedule there have been declines in VT pneumococcal colonisation and disease in children aged <5 years. Modelling of dominant serotype colonisation data produced plausible vaccine effectiveness estimates. |
Lessons learned from emergency response vaccination efforts for cholera, typhoid, yellow fever, and Ebola
Walldorf JA , Date KA , Sreenivasan N , Harris JB , Hyde TB . Emerg Infect Dis 2017 23 (13) S210-6 Countries must be prepared to respond to public health threats associated with emergencies, such as natural disasters, sociopolitical conflicts, or uncontrolled disease outbreaks. Rapid vaccination of populations vulnerable to epidemic-prone vaccine-preventable diseases is a major component of emergency response. Emergency vaccination planning presents challenges, including how to predict resource needs, expand vaccine availability during global shortages, and address regulatory barriers to deliver new products. The US Centers for Disease Control and Prevention supports countries to plan, implement, and evaluate emergency vaccination response. We describe work of the Centers for Disease Control and Prevention in collaboration with global partners to support emergency vaccination against cholera, typhoid, yellow fever, and Ebola, diseases for which a new vaccine or vaccine formulation has played a major role in response. Lessons learned will help countries prepare for future emergencies. Integration of vaccination with emergency response augments global health security through reducing disease burden, saving lives, and preventing spread across international borders. |
Considerations for use of Ebola vaccine during an emergency response
Walldorf JA , Cloessner EA , Hyde TB , MacNeil A . Vaccine 2017 37 (48) 7190-7200 Vaccination against Ebola virus disease is a tool that may limit disease transmission and deaths in future outbreaks, integrated within traditional Ebola outbreak prevention and control measures. Although a licensed Ebolavirus vaccine (EV) is not yet available, the 2014-2016 West African Ebola outbreak has accelerated EV clinical trials and given public health authorities in Guinea, Liberia, and Sierra Leone experience with implementation of emergency ring vaccination. As evidence supporting the use of EV during an outbreak response has become available, public health authorities in at-risk countries are considering how to integrate EV into future emergency Ebola responses and for prevention in high-risk groups, such as healthcare workers and frontline workers (HCW/FLWs), even before an EV is licensed. This review provides an overview of Ebola epidemiology, immunology, and evidence to inform regional and country-level decisions regarding EV delivery during an emergency response and to at-risk populations before a licensed vaccine is available and beyond. Countries or regions planning to use EV will need to assess factors such as the likelihood of a future Ebolavirus outbreak, the most likely species to cause an outbreak, the availability of a safe and effective EV (unlicensed or licensed) for the affected population, capacity to implement Ebola vaccination in conjunction with standard Ebola outbreak control measures, and availability of minimum essential resources and regulatory requirements to implement emergency Ebola vaccination. Potential emergency vaccination strategies for consideration include ring or geographically targeted community vaccination, HCW/FLW vaccination, and mass vaccination. The development of guidelines and protocols for Ebola vaccination will help ensure that activities are standardized, evidence-based, and well-coordinated with overall Ebola outbreak response efforts in the future. |
Recovery of HIV service provision post-earthquake
Walldorf JA , Joseph P , Valles JS , Sabatier JF , Marston BJ , Jean-Charles K , Louissant E , Tappero JW . AIDS 2012 26 (11) 1431-6 OBJECTIVE: To describe the level of functionality of President's Emergency Plan for AIDS Relief (PEPFAR)-supported HIV clinical services following the devastating earthquake that struck Haiti in January 2010. DESIGN: Available program-monitoring data from sites providing voluntary counseling and testing for HIV (VCT), antenatal care (ANC) and prevention of mother-to-child transmission (PMTCT) services, and antiretroviral treatment (ART) were described, comparing pre-earthquake and post-earthquake periods during October 2008 to May 2010. METHODS: Pre-earthquake HIV service baselines for VCT, PMTCT, and ART enrollment were defined as monthly mean total number of patients served over 15 months pre-earthquake. ART baseline was defined as total current patients by December 2009. Sites were categorized as high-earthquake or low-earthquake intensity based on location and instrumental shake intensity data. RESULTS: Pre-earthquake mean monthly baselines were 41,087 (VCT), 11,909 (HIV testing at ANC sites), 648 (ART enrollment), and 296 (PMTCT enrollment); baseline total current patients on ART was 24,863. Service provision in January and May 2010, reported as percentage of baseline, was 43 and 78.7% (VCT), 50.8 and 88.7% (HIV testing at ANC), 46 and 81% (PMTCT), and 41 and 82.7% (ART enrollment), respectively. Current patients on ART decreased to 97% of baseline in April, rising to 103.9% by May; the initial decline was restricted to high-earthquake intensity areas. CONCLUSION: Following the Haiti earthquake, there was a transient, marked decline in VCT and new ART patient enrollment, whereas follow-up of established ART patients remained impressively high. HIV treatment continuity should be reinforced in disaster preparedness and response strategies in HIV epidemic settings. |
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