Zero-dose or under immunized: Where should the emphasis lie?

Abstract

Vaccine preventable diseases (VPD) pose significant morbidity and mortality globally. Two years after the endorsement of Immunization Agenda 2030 (IA2030), the number of children not fully vaccinated increased from 19 million pre-COVID-19 to 25 million post-COVID, with 72% (18.2 million) of these labelled as zero-dose, i. e those who did not receive DPT 1 vaccine. While children who do not initiate vaccination early (zero-dose) may be at a greater risk of missing subsequent vaccinations, we most respectfully suggest that this term zero-dose may be problematic, lending itself to misconceptions among policy makers and health professionals. Firstly, zero-dose is currently set at six weeks DPT1 vaccination point and not at birth for children 12-23 months of age. Secondly, assessing zero-dose in children 12 to 23 months of age, delays corrective or remedial action because by month 12, the children have missed key vaccines before they are flagged as zero dosers. Thirdly, in poor settings, many children who initiate vaccination do not complete the schedule, with DPT1 coverage always higher than measles vaccine coverage. Additionally, the children in poor countries who miss the first DPT dose face similar challenges and deprivations and barriers as those who fail to complete their immunization schedule. The problems of poverty, inability to fully access immunization services, hesitant caregivers and poorly equipped immunization programs affect all children across sub–Saharan Africa and other poor countries. This review seeks to discuss the importance of looking at the entire recommended immunization schedule over and above highlighting those who miss DPT1 alone and proposes that “under-immunized” children as an entity be equally emphasized as “zero dose” children in low- and middle-income countries to ensure that adequate attention is given to both vulnerable groups.