Project in India

Impact of biologic and socio-economic disparities on routine vaccination coverage, timeliness and efficacy in a developing country setting

Investigators

Joseph L. Mathew, MD, PhD, Professor, Department of Pediatrics, Postgraduate Institute of Education and Research, Chandigarh, India 160012, and Matthew L. Boulton, MD, MPH, Department of Epidemiology, School of Public Health, and, Department of Internal Medicine, Infectious Diseases Division, Medical School, University of Michigan

Purpose

To study the impact of biologic and socio-economic disparities on routine vaccination coverage, timeliness and efficacy in a developing country setting.

Rationale

The Universal Immunization Programme (UIP) in India delivers multiple vaccines to all infants and children, from birth through childhood. These vaccines are delivered free of cost, and are easily accessible throughout the country. It is estimated that over 90% vaccinations are provided through the free of cost public health care system. Despite this, the overall vaccination coverage remains unacceptably low across India, and the vaccine preventable diseases continue to be prevalent. The latest National Family Health Survey – 4, conducted during 2015 -16  reported that only 62% infants in the age group 1-2 years had received BCG and 3 doses each of DPT and oral polio vaccines. However, there was no data on the timeliness of these vaccinations. This means that a significant proportion of infants and children remain unprotected against diseases with serious consequences, even if they ultimately receive the vaccines. Further, aggregate data suggested that infants of mothers with no education were far less likely to be vaccinated (52%) compared to those born to mothers with secondary or higher education (67%). Similarly, there was a rising trend of vaccination coverage from the lowest to the highest wealth quintile.

Chandigarh is a union territory located in northern India. On the one hand it is hailed as a high economic, high technology user city. On the other hand, it has a significant proportion of people living in rural or urban resettlement (formerly called slum) areas. The vaccination data for Chandigarh in the National Family Health Survey was available through interview of a very small number (25-49) of participants making the data somewhat unreliable. A brief summary of the key statistics compared to the overall data for India is shown below.

Parameter Chandigarh India
Birth weight <2.5 kg 22.2% 18.2%
Birth size very small or smaller than average 10.9% 12.1%
BCG vaccination 95.9% 91.9%
DPT 1 95.9% 89.5%
DPT 2 95.9% 85.7%
DPT 3 95.9% 78.4%
OPV1 92.7% 90.8%
OPV2 90.1% 86.0%
OPV3 79.5% 72.8%
Measles vaccination 95.9% 81.1%
All vaccines received 79.5% 62.0%

The data suggest that the true picture of vaccination coverage is most likely masked by the inadequate sample size. Further, although country-wide data on disparities in vaccination coverage by certain biologic and/or socio-economic indicators is recorded in the NFHS-4 report, similar data for Chandigarh is not reported.

This study is designed to understand the impact of biologic and socio-economic disparities on routine vaccination coverage, timeliness and efficacy in Chandigarh.

Study design and methods

We will select 30 anganwadi clusters from the 500 such clusters in the Union territory of Chandigarh, through a random sampling procedure. The 30 selected clusters will be distributed across areas of the union territory labelled as urban, rural and urban resettlement- in the proportion representing the population distribution of Chandigarh. From each cluster, purposive random sampling will be undertaken to identify 600 infants in the age group 9-12 months whose data on the following characteristics is available: Date of birth, Birth weight, Gestational age at birth, Maternal age at birth, Birth order, Gap between preceding birth and succeeding birth, maternal education level, household income, and family structure (joint or nuclear). Vaccination status with respect to BCG vaccine, three doses DPT, OPV, Hepatitis B and measles vaccine will be recorded by inspection of the vaccination card to assess (i) receipt (yes/no) and (ii) timeliness (described as timely if  received on the scheduled date + 2 weeks for all vaccines). Infants will be grouped into categories based on their disparities as follows: (i) Low birth weight (ie <2.5 kg) versus other, (ii) Premature gestation (ie <37 weeks) versus other, (iii) High birth order (ie greater than first/second birth order) versus other, (iv) Low gap between births (ie gap less than 18 months from preceding/succeeding birth) versus other, (v) Low maternal education (ie less than Class V) versus other, (vi) Low household income (ie less than Rs 10,000/- per month) versus other, and (vii) Family structure (ie joint versus nuclear). Thus each infant has the potential to have 7 disparities, resulting in eight categories based on having 0 to 7 disparities. Vaccination coverage and timeliness will be assessed for each of these eight groups. Vaccination efficacy will be assessed in these infants by observing the BCG scar (as a surrogate indicator of BCG vaccination) and measuring serum IgG antibody levels against Diphtheria toxoid, Tetanus toxoid, one component of the Pertussis antigen, Hepatitis B surface antigen, PRPP component of Hib, and measles. Data will be analyzed and compared across the 8 groups. Antibody levels will be measured by ELISA using commercially available kits, following the manufacturers’’ instructions.

Anticipated undergraduate/graduate student activities on project

The student(s) will participate in: (i) obtaining of written informed consent for the study procedures, (ii) conducting interviews in field to obtain the data required, and (iii) assisting with blood sample collection in the field, (iv) assisting with basic laboratory procedures such as separation of serum from blood, (v) assisting with the ELISA methods to measure antibody levels, and (vi) data recording and analysis.

Techniques/methods students should become familiar with in advance

  1. Basic laboratory procedures.

 Suggested readings (minimum of 3-5 articles)

  1. International Institute for Population Sciences (IIPS) and ICF. 2017. National Family Health Survey (NFHS-4), 2015-16: India. Mumbai: IIPS. Available from: http://rchiips.org/NFHS/NFHS-4Reports/India.pdf. Accessed: 05 October 2018.
  2. Shenton LM, Wagner AL, Bettampadi D, Masters NB, Carlson BF, Boulton ML. Factors Associated with Vaccination Status of Children Aged 12–48 Months in India, 2012–2013. Matern Child Health J 2017. DOI:10·1007/s10995-017-2409-6.
  3. Shrivastwa N, Gillespie BW, Lepkowski JM, Boulton ML. Vaccination Timeliness in Children under India’s Universal Immunization Program. Pediatr Infect Dis J 2016; 35: 955–60.
  4. Mathew JL. Inequity in Childhood Immunization in India: A Systematic review. Indian Pediatr 2012; 49: 203-223.
  5. Mathew JL. Evidence-Based Options to Improve Routine Immunization. Indian Pediatr 2009; 46: 993-996.