What the study found
Many children in low-income and middle-income countries (LMICs) receive vaccines later than the ages recommended. Across 91 countries, the study found delays for several vaccines, including BCG, hepatitis B birth dose, polio, diphtheria-tetanus-pertussis-containing vaccines, pneumococcal conjugate vaccine, rotavirus vaccine, and measles-containing vaccine.
Why the authors say this matters
The authors conclude that strategies to increase vaccine impact should be informed by systematic evidence on vaccine timeliness. The study suggests that knowing not just whether children are vaccinated, but when they are vaccinated, is important in LMICs.
What the researchers tested
The researchers analyzed survey data from 91 LMICs, using 45 Demographic and Health Surveys and 46 Multiple Indicator Cluster Surveys conducted between 2010 and 2019. They estimated coverage by day of age for children younger than 3 years, and measured how early, timely, or late each dose was compared with its target age.
What worked and what didn't
Vaccination was often late rather than timely. The median net mean delay was 3.3 weeks for BCG, 3.7 weeks for DTP1, 5.2 weeks for DTP2, 7.7 weeks for DTP3, 5.5 weeks for MCV1, and 5.4 weeks for MCV2; the median percentage of timely doses ranged from 79% for BCG to 50% for DTP3 and MCV2. Coverage also increased with age for several vaccines, such as BCG from 73% at 1 month to 93% at 6 months, DTP3 from 47% at 6 months to 76% at 12 months, and MCV1 from 53% at 12 months to 81% at 18 months. Co-recommended vaccines had similar timeliness but lower coverage.
What to keep in mind
The summary does not describe limitations beyond the use of survey data from specific countries and years. Results are based on 91 LMICs and the surveys available between 2010 and 2019.
Key points
- Across 91 LMICs, many children were vaccinated later than the recommended target age.
- Median delays were 3.3 weeks for BCG and 7.7 weeks for DTP3.
- The median share of timely doses was 79% for BCG, 70% for DTP1, and 50% for DTP3 and MCV2.
- Coverage rose with age for BCG, DTP3, and MCV1 in the reported medians.
- Co-recommended vaccines had similar timeliness but lower coverage.
Disclosure
- Research title:
- Vaccination in LMICs is often delayed beyond target ages
- Authors:
- Andrew D. Clark, Daniel R Feikin, M Carolina Danovaro-Holliday, Colin F B Sanderson
- Institutions:
- London School of Hygiene & Tropical Medicine, World Health Organization
- Publication date:
- 2026-04-23
- OpenAlex record:
- View
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