NEW DELHI: Majority of children aged 5-17 years in India are either only partially or non-immune to diphtheria, leading to its re-emergence as a public health challenge despite vaccine being against the infectious disease being part of the national immunisation programme for over four decades.
The revelation has come out in a serosurvey carried out by the ICMR’s National Institute of Epidemiology. diphtheria, a bacterial disease, was a leading cause of childhood morbidity and mortality in the pre-vaccination era and a vaccine against was included in the country’s national immunisation programme in 1978 as DTP vaccine.
A pentavalent vaccine, which provides protection against diphtheria, pertussis, tetanus, hepatitis B, and Haemophilus influenzae, was introduced in India in a phased manner in 2011, and covered the entire country by 2015.
The schedule for primary vaccination consists of three doses of diphtheria vaccine administered at ages 6, 10, and 14 weeks, and is followed by two booster doses, the first given between the ages of 16 and 24 months and the second between the ages of 5 and 6 years. The survey, however, found that only about 29% of 8,309 children, samples from whom were tested for antigen against diphtheria pathogen, aged 5–17 years were immune to diphtheria, 10.5% were non-immune, and 59.8% were partially immune.
The proportion of children who were non-immune to diphtheria ranged from 6% in the south to 16.8% in the northeast. Overall, 9.9% of children residing in rural areas and 13.1% in urban areas were not immune to diphtheria. The study, published in the Lancet says that while the coverage of the three primary doses of diphtheria vaccines was estimated to be 78.4% during 2015–16, but reliable information about coverage of booster doses is not available in India as it is not routinely collected.