Immunisation coverage and antibiotic use: is India missing an opportunity?

Studies now indicate that unvaccinated or under-vaccinated children are vulnerable to preventable illnesses and have to seek medical care, which in many cases leads to an unnecessary abuse of antibiotics, fueling the epidemic of antimicrobial resistance

Immunisation has been one of the biggest success stories in public health globally, second only to sanitation and water safety. Vaccination has led to the eradication of sand polio in India, which are no longer the scourges they used to be. However, our vaccination initiatives in the country still leave many opportunities underutilised, leading to an actual cost to be paid in the future.

The COVID-19 pandemic has shown the benefit of vaccination at all ages as well as the importance of sensitising the general public and administrators on the need for adult vaccinations. Unfortunately, the related lockdowns also massively disrupted childhood vaccine programmes globally. UNICEF data from 2023 reveals that 73 countries reported a significant (>5%) decline in childhood vaccination rates post pandemic. Of these, only 15 returned to pre-pandemic levels, while 24 are recovering and 34 have stayed unchanged or worsened. India has been noted as one of the success stories in this regard, with recovery on the ground based on the successful completion of the third dose of the DPT vaccine.

Lack of data on disease burdens

While India’s success post pandemic is laudable, unfortunately, we do not have accurate data on the scenario with many other vaccines -- for instance, the vaccine against pneumococcal pneumonia (pneumococcal conjugate vaccine- PCV) and the Haemophilus influenzae vaccine (Hib). These two vaccines are fairly recent additions to the government’s immunisation program, and were designed for rapid upscale when COVID-19 hit. Data on these burden from these two pathogens is not currently available, but the last estimate from 2015 had placed it at 1.84 million cases and 84,000 deaths.

The significance of this lies in the fact that these two pathogens -- Streptococcus pneumoniae and  Haemophilus influenzae -- are a leading cause of upper and lower respiratory infections in all decades of life, and are an important concern for children under five. They are amongst the commonest causes of ear infections (otitis media), lung infections (pneumonia) and brain infections (meningitis). Some of these problems are life-threatening and survivors can be left with long-term complications.

The introduction of the PCV as a childhood vaccine has been achieved in most developed countries across the globe, as well as in 60 of the 73 Gavi vaccine alliance eligible countries. This has resulted in a steep fall in pneumonia cases in children, as well as deaths. A paper in 2020 estimated a reduction of 175 million infections as a result of vaccination of infants, in addition to the prevention of about 6,25,000 deaths over a 10-year period.

What happens to the unvaccinated/under-vaccinated?

Whilst the direct, short-term effects are often reported on, what is generally not recognised is that non-vaccination fuels a larger problem that is of global concern. Studies now indicate that unvaccinated or under-vaccinated children are vulnerable to preventable illnesses and have to seek medical care, which in many cases leads to significant out-of-pocket expenditure, as well as, crucially, often unnecessary abuse of antibiotics, fueling the epidemic of antimicrobial resistance. Also of concern is that this disproportionately affects the most vulnerable parts of society, increasing costs for them.

South and Southeast Asia account for 6.5% of global antibiotic usage, including 54.9% of the World Health Organization ‘Watch’ classified antibiotics. This has set off alarm bells, and compounded by the problem of extensively drug-resistant infections set against a practically dry drug development pipeline, is a nightmare in the making. Many interventions are being designed to address this as part of the ‘One Health’ approach, but the value of vaccination in reducing antibiotic use has not been given enough attention. In financial terms, AMR could result in an annual loss of 5-7% of India’s GDP by 2050.

A recent paper in The Lancet Regional Health South Asia by Chirag Kumar and his colleagues has assessed the possible benefits of increasing coverage of both these vaccines. The assessment was of vaccine coverage across India, and the anticipated benefits in terms of reduction of infection rates from the two pathogens mentioned above, and the potential reduction in antibiotic use fueled by these illnesses.

Firstly, there is an expectation of a significant reduction in the disease burden, and the benefit, the paper found, would be striking in vulnerable states including Rajasthan, Madhya Pradesh, Odisha and West Bengal. There is also an anticipated fall in the disease burden and mortality all groups, irrespective of economic background. If the population were subdivided by wealth, the benefit would be greatest -- including in mortality reduction -- in those most economically disadvantaged. In addition, the estimate is of a reduction of 67,000 deaths a year.

Secondly, on the issue of antibiotic abuse, the model strongly indicates a meaningful reduction in antibiotic consumption in children, and this fall would be most pronounced in the economically advantaged group due to cost reasons. However, this reduction in usage could lead to more equitable usage of antibiotics, and reduction in the burden amongst those most economically disadvantaged.

Other outcomes like hospital visits, and the need for admissions was not estimated, and these could indeed prove to be another significant benefit, as this could reduce pressure on an overburdened public health system. In fact, a study from Ecuador in 2020 has noted a fall in pneumonia hospitalizations in the under-one year age group by 27% and by 33% in the under-five category.

Overall, this is an area that needs a lot more attention, and steps taken by the government are bearing fruit, as witnessed by the return to pre COVID-19 rates in childhood vaccination for DPT. More measures to improve uptake of the PCV and Hib vaccine could certainly improve health indices and result in benefits that are not being routinely monitored but which could have widespread impacts.

(Dr. Subramanian Swaminathan is Director- Infectious Diseases and Infection Control, GHC, Chennai and Bengaluru and Vice President, Clinical Infectious Diseases Society of India. drsubramanians@gmail.com)

Published - November 18, 2024 06:00 am IST