Over the last 20 years, international organizations spearheaded by GAVI, the Vaccine Alliance—in partnership with national governments, the World Health Organization and UNICEF—have ensured that significantly more children in poor countries in Africa and elsewhere get routine vaccinations. 81 per cent to-day versus 59 per cent in 2000. And that has had a major impact—a 70 per cent drop in child mortality from vaccine-preventable diseases over two decades.

But what about the root causes of non-vaccination of the young：is the problem one of poverty alone, of the failure of domestic governments and their public-health departments to reach the most vulnerable communities, or simply of an inability to overcome deep-rooted social disadvantages? A new Canada-India study of tens of thousands of zero-dose children in India suggests that the cause of low-vaccination rates in lower-income countries is all of those and more.

The study analyses a quarter century of national survey data to better understand how social, economic and geographical inequalities in India shaped the chances of children remaining unvaccinated between 1992 and 2016. They found that India had made tremendous progress in reaching children with routine immunisation. But they also found that, in 2016, children remained concentrated among disadvantaged groups, including the lowest-income households and children born to mothers who had no formal education.

As well, compared with vaccinated children, zero-dose children were more likely to suffer from malnutrition. For instance, in 1992, 41 percent of zero-dose kids had severely stunted growth; by 2016, the numbers had declined but were still disproportionate. “Over a 24-year period in India, child zero-dose status was shaped by large-scale social inequalities and remained a consistent marker of generalised vulnerability, “the researchers concluded. “Interventions that address this cycle of intergenerational inequities should be prioritised. “

Professor Johri pointed to the uniqueness of the work of her and her colleagues. “It’s the first to trace aggregate patterns in zero-dose children over time globally and in India, “said Johri, who is an overseas citizen of India as well as a Canadian citizen.

More globally, the Indian experience suggests that “child zero-dose vaccination status is an important marker of vulnerability linked to systematic disadvantage over the life course, “Johri said. “Identifying zero-dose children and intervening early to address the complex sources of disadvantage they face has the potential to transform life opportunities and combat intergenerational inequities. It should be a top priority for the international community.”

What are the basic reasons of zero-vaccination of the children in poor countries?