A review of the current diphtheria outbreaks

Corynebacterium diphtheriae is responsible for both endemic and epidemic diphtheria. The predisposing factor for this disease is the failure to immunize during childhood. Humans are the only hosts of the organism and is present in the upper respiratory tract. The organism is transmitted via airborne route and can cause respiratory obstruction and heart failure because of the exotoxin it produces. There is presently a resurgence of diphtheria outbreaks in Nigeria. The Nigeria Center for Disease Control (NCDC) was notified of suspected diphtheria outbreaks in Lagos and Kano States, Nigeria, in December 2022 and has been issuing monthly reports since that time. This review of the diphtheria outbreaks following online database searches on PubMed and Google Scholar as well as the NCDC/WHO websites and grey literatures, describes the current trend of the outbreaks globally, elucidated the different strains of Corynebacterium responsible for the outbreaks, identified the recent vaccine formulation developed to tackle the outbreaks, and provide information on vaccine delivery and efficacy studies in the country and globally.

State of equity: childhood immunization in the World Health Organization African region

Introduction: in 2010, the Global Vaccine Action Plan called on all countries to reach and sustain 90% national coverage and 80% coverage in all districts for the third dose of diphtheria-tetanus-pertussis vaccine (DTP3) by 2015 and for all vaccines in national immunization schedules by 2020. The aims of this study are to analyze recent trends in national vaccination coverage in the World Health Organization African Region and to assess how these trends differ by country income category.Methods: we compared national vaccination coverage estimates for DTP3 and the first dose of measles-containing vaccine (MCV) obtained from the World Health Organization (WHO)/United Nations Children's Fund (UNICEF) joint estimates of national immunization coverage for all African Region countries. Using United Nations (UN) population estimates of surviving infants and country income category for the corresponding year, we calculated population-weighted average vaccination coverage by country income category (i.e., low, lower middle, and upper middle-income) for the years 2000, 2005, 2010 and 2015.Results: DTP3 coverage in the African Region increased from 52% in 2000 to 76% in 2015,and MCV1 coverage increased from 53% to 74% during the same period, but with considerable differences among countries. Thirty-six African Region countries were low income in 2000 with an average DTP3 coverage of 50% while 26 were low income in 2015 with an average coverage of 80%. Five countries were lower middle-income in 2000 with an average DTP3 coverage of 84% while 12 were lower middle-income in 2015 with an average coverage of 69%. Five countries were upper middle-income in 2000 with an average DTP3 coverage of 73% and eight were upper middle-income in 2015 with an average coverage of 76%.Conclusion: disparities in vaccination coverage by country persist in the African Region, with countries that were lower middle-income having the lowest coverage on average in 2015. Monitoring and addressing these disparities is essential for meeting global immunization targets

Missed opportunities and barriers for vaccination: a descriptive analysis of private and public health facilities in four African countries

Introduction: missed opportunities and barriers to vaccination limit progress toward achieving high immunization coverage and other global immunization goals. Little is known about vaccination practices contributing to missed opportunities and barriers among private healthcare providers in Africa.Methods: Service Provision Assessments (SPA) of representative samples of health facilities in four African countries (Kenya, Tanzania, Senegal, Malawi) in 2010-2015 were used to describe missed opportunities and barriers for vaccination in public, private for-profit, private not-for-profit and faith-based facilities. Data included vaccination practices, observations during sick child and antenatal visits, and exit interviews following sick child visits.Results: data from 3,219 health facilities, 11,613 sick child visits and 8,698 antenatal visits were included. A smaller proportion of for-profit facilities offered child vaccination services (country range, 25-37%) than did public facilities (range, 90-96%). The proportion of facilities offering pentavalent vaccine (diphtheria, pertussis, tetanus, hepatitis B and Haemophilus influenza type b antigens) daily ranged 0-77% across countries and facility types. Less than 33% of for-profit facilities in any country offered measles vaccination daily. A minority of public or private providers assessed the child's vaccination status during a sick child visit (range by country and facility type, 14-44%), or offered tetanus toxoid during antenatal visits (range, 19-51%). Very few providers discussed the importance of newborn vaccination. Conclusion: substantial missed opportunities for, and barriers to, vaccination were identified across this representative sample of health facilities in four African countries. Strategies are needed to ensure that private and public providers implement practices to minimize barriers and missed opportunities for vaccination