Waning rate of immunity and duration of protective immunity against diphtheria toxoid as a function of age and number of doses: Systematic review and quantitative data analysis

ABSTRACT

Although the burden of diphtheria has declined greatly since the introduction of vaccines, sporadic outbreaks continue to be reported. WHO recommends booster doses after a primary series, but questions remain about the optimal interval between these doses. We conducted a systematic review and quantitative data analysis to quantify the duration of protective immunity after different numbers of doses. Fifteen cross-sectional seroprevalence studies provided data on geometric mean concentration (GMC). Single-year age-stratified GMCs were analyzed using a mixed-effect linear regression model with a random intercept incorporating the between-country variability. GMC was estimated to decline to 0.1 IU/ml in 2.5 years (95% CI: 0.9–4.0), 10.3 years (95% CI: 7.1–13.6), and 25.1 years (95% CI: 7.6–42.6) after receiving three, four and five doses, respectively. The results drawn from cross-sectional data collected in countries with different epidemiologies, vaccines, and schedules had several limitations. However, these analyses contribute to the discussion of optimal timing between booster doses of diphtheria toxoid-containing vaccine.

KEYWORDS:

• Antibody
• diphtheria
• DTP
• immunity
• systematic review
• vaccination

Acknowledgments

We thank John W Edmunds who shared the original data for analysis. We acknowledge the Library Services of the London School of Hygiene and Tropical Medicine, UK, and Nagasaki University, Japan, who supported the construction of the search terms and provided the full articles.

Disclosure statement

The authors report there are no conflict of interest.

Author contributions

NK designed and conducted the systematic review, conducted the quantitative analysis, and drafted the manuscript.

NK and KB equally contributed to screening articles and investigating the quality assessment of included studies.

NK and EC equally contributed to extracting data from included studies.

BJQ and TE supported the statistical data analysis, contributed to interpreting the data, and revision of the draft.

MT and LMY contributed to interpreting the data and revision of the draft.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.