“I was born in Jhunjhunu, Rajasthan, in 1997. Due to a severe lack of awareness around the routine immunisation programme and lack of access to healthcare, I did not get any vaccinations at birth,” says Pinky Maharia, an MBBS graduate from Sewagram, Maharashtra. “It was only thanks to the pulse polio program, which administered the oral polio vaccine from home to home, that I ended up receiving one vaccine eventually.”
According to the current World Health Organization definition, Dr. Maharia would have been considered a zero-dose child during her infancy. A zero-dose child is defined as a child under the age of one, who has not received even a single dose of routine vaccines recommended for childhood immunisation. An analysis, published a few days ago in The Lancet on the Global Burden of Diseases Study, estimates that an alarming 1.44 million zero-dose children live in India, based on 2023 data. This is the second-highest number of zero-dose children globally, second only to Nigeria. According to this analysis, nearly half of the zero-dose children worldwide reside in only eight countries, all of which are located in the African, South Asian, and Southeast Asian regions.
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Why zero-dose children are a cause of concern
When growing up, zero-dose children not only find themselves at a higher lifetime risk of vaccine-preventable diseases such as diphtheria, measles, whooping cough, poliomyelitis, and tetanus, but they also threaten the elimination of these diseases from the community. Following the COVID-19 outbreak, which created a gap in routine vaccinations, India reported measles outbreaks from States including Maharashtra, as evidenced by this trend. While some of these illnesses cause only harm to the person affected, many also lead to long-term complications, such as long-term disability in people who have had poliomyelitis and a life-threatening neurological condition known as SSPE (Subacute Sclerosing Panencephalitis) after measles.
According to WHO data, from 2010 to 2018, nearly 23 million deaths were prevented globally using the measles vaccine alone. This demonstrates that vaccines and routine childhood immunisation have been highly successful preventive public health interventions. Considering this data, the WHO has set an ambitious goal to halve the number of children without a dose by 2030.
However, the global trends for reducing zero-dose children were severely impaired by the COVID-19 pandemic. For two years or more, as the pandemic raged on, routine immunisation was deprioritised, leading to a surge in the number of zero-dose children—a trend that is slowly recovering now. As of 2023, the number of zero-dose children had not yet recovered to pre-pandemic levels.
While this number of zero-dose children itself appears alarming, this number is only the tip of the iceberg as many other children are partially or incompletely vaccinated as well.
What the zero-dose metric misses: partial and incomplete vaccination
Radhikaa Sharma, a postgraduate in community medicine, recently found her vaccination card, which led her to realise that she had only received one dose of the recommended routine vaccines administered at birth. She was not vaccinated against measles or rubella, and had eventually ended up contracting measles during her childhood.
Studies would not have classified Dr. Sharma as a zero-dose child, and yet, she was vulnerable because of partial vaccinations.
This reveals that even among the children who aren’t zero-dose, there is no guarantee that they have received an adequate dose of vaccinations needed to protect them from these illnesses.
Furthermore, many of these vaccines must be administered at the recommended age for them to be effective and life-saving. Indu Subramaniam, an Indian-origin neurologist based in Los Angeles, United States, had recently written about her cousin who died after developing SSPE, after having had measles in his childhood. SSPE more commonly occurs in children who get measles before the age of 18 months, according to research, and missing this crucial early infancy period to vaccinate could potentially be life-threatening for these unvaccinated children.
The uncounted unvaccinated
It is also important to note that the 1.44 million figure refers only to children under the age of one who have not received any routine vaccinations. This figure is a snapshot of the number of infants currently in that vulnerable, unprotected state within a given year. This number does not account for the children who were zero-dose in previous years and have since grown older but remain unvaccinated.
In other words, while the 1.44 million reflects the current annual burden of zero-dose infants, it does not capture the cumulative pool of older children who have aged beyond one year without receiving their routine vaccinations. This group could include children who were missed during periods of disrupted services, such as during the COVID-19 pandemic, or who have been persistently excluded from immunisation efforts due to factors like geographic isolation, poverty, displacement, or social marginalisation.
Unvaccinated children are clustered not scattered
Beyond the gross number of unvaccinated children, the Lancet data tells an important story, according to Raj Shankar Ghosh, a public health expert with a special interest in immunisation.
“When we think of these 1.44 million children, we must understand that they are not evenly distributed across the country. 0.11% zero-dose children does not mean one unvaccinated child living among 999 vaccinated children, thus protected from this disease by herd immunity. These unvaccinated children are localised in pockets across the country, living among other unvaccinated children, which increases their risk of their being susceptible to these vaccine-preventable diseases,” he says.
According to Dr. Ghosh, another common factor noted about these pockets where unvaccinated children reside, is that there is also a lack of other public health services such as nutrition and sanitation in these areas, making these children further vulnerable to health complications. An equity analysis on zero-dose children documented in National Family Health Survey – 5 (NHFS-5) data revealed that geographically, more than 50% of zero-dose children in India were located in three key areas – urban slums, conflict areas, as well as remote and difficult-to-reach communities.
The government, along with UNICEF, Gavi, the Vaccine Alliance, and other partners, is working to reach these specific underserved communities.
According to Dr. Ghosh, there have been some innovative ways in which health workers have been trying to vaccinate these underserved communities. “In several States in North-East India, for example, health workers are trying to vaccinate children in weekly markets. In many cases in these far-off areas, parents who work as daily wage labourers cannot afford to take time off to take their children to vaccination centres. By meeting the mothers and children in markets, the health workers can bridge this gap by ensuring that the child is vaccinated without disrupting the parents’ day and ensuring that they do not lose any wages.”
Similarly, many States have begun offering door-to-door vaccination to ensure these communities are reached. These are special immunisation drives conducted by local authorities to ensure that no child is left behind from their routine immunisation. Such hyperlocal and community context-sensitive measures need to be scaled up to ensure that all unvaccinated children are reached, according to Dr. Ghosh.
What is already working and what needs more work
Warisha Mariam, a public health expert, says that the Indian government is working on multi-pronged approaches to ensure that not only are these zero-dose children reached, but also that older children who have missed their routine vaccine doses are given ‘catch-up’ vaccinations against Diphtheria, Pertussis, and Tetanus (DPT).
In 2024, Central and State governments partnered to develop a zero-dose implementation plan for 143 of the most vulnerable districts in 11 States, to reach the most underserved communities. With UWIN, a portal launched to record immunisations of newborns and pregnant women digitally while also keeping track of vaccine supply chains, and Mission Intensified Indhradhanush, where cycles of immunisation campaigns for routine vaccines are conducted, the government aims to intensify its Universal Immunisation Programme to help reach the WHO goals to halve the number of zero-dose children globally, by 2030.
The problem with UWIN, however, is that it requires smartphone access to provide OTPs and documentation, such as Aadhaar cards, which are often lacking, particularly in vulnerable communities, including migrant workers who may lack both. Adapting the UWIN technology in a way that the most vulnerable populations without phones and documentation are also included is crucial. Further, community engagement activities, partnering with local grassroots organisations, civil society organisations and school awareness programs are already underway and help in improving vaccine coverage.
“Vaccination should not be considered in a silo,” says Dr. Ghosh, who admits that while India is emerging as a global leader in vaccination and is probably in the last mile of its journey, the most challenging part is yet to come. “It is not about reaching the target indicators but sustaining them.”
Towards sustaining immunisation targets
Dr. Ghosh says that while many countries with strong immunisation programmes have reached their preferred targets, they have issues sustaining it. “This is because there is no appropriate awareness in the communities about the need for vaccination and once universal vaccination is achieved and these diseases disappear from public consciousness, people also forget why they are needed.”
According to Dr. Ghosh, immunisation is successfully sustained only when a community inherently understands the need for vaccination and generates a demand for vaccines. India must strive towards this goal. To achieve this, vaccination needs to be offered as an integrated package, alongside appropriate nutrition, sanitation, and access to other healthcare services, along with health education that fosters awareness. A holistic view of immunisation established in this way is what will help India sustain vaccination targets long after it achieves them.
Dr. Maharia is now considering whether getting vaccinated for measles, mumps, and rubella before planning a pregnancy is the right option for her. These diseases are known to carry significant risks for pregnant women with low immunity, including miscarriages, birth defects, and serious illnesses for the baby. Since live vaccines such as MMR are not recommended during pregnancy, Dr. Maharia may only be able to receive them before conceiving or after childbirth — a choice she now has because she has the knowledge and awareness to understand the importance of vaccinations. And this is the kind of demand for immunisation that India must hope to create in every community to sustain its immunisation targets.
(Dr. Christianez Ratna Kiruba is an internal medicine doctor with a passion for patient rights advocacy. christianezdennis@gmail.com)
