The country has reduced the number of children who had never been vaccinated by half, according to The Lancet.
Nepal has met the World Health Organisation's Immunisation Agenda 2030 by halving the number of zero-dose children -- those who have never received even a single dose of routine vaccines -- in 2023, seven years ahead of schedule.
According to a report published in The Lancet, a leading international medical journal, apart from reducing the number of zero-dose children by 50 percent, the country is also in line to achieve 90 percent coverage of diphtheria, pertussis and tetanus (DPT3), pneumococcal conjugate Vaccine (PCV3) and the second dose of the measles-containing vaccine.
Along with Nepal, Bangladesh in South Asia has also achieved the target.
Health officials credited Nepal's immunisation priority and repeated drive to find zero-dose children for the early success.
"We launched intensive campaigns to find zero-dose children, reached every household and made sure that no children missed routine vaccines," said Dr Abhiyan Gautam, chief of the Immunisation Section at the Family Welfare Division under the Department of Health Services.
"During the campaigns, we detected hundreds of children who had either not received a single dose of routine vaccines or had not received all vaccines in the routine list, and inoculated them."
The government has declared all seven provinces and 77 districts fully immunised.
The Health Ministry started declaring fully immunised villages about two decades ago as a pilot project to boost the coverage of routine vaccines.
Studies carried out in the past, including the Nepal Demographic and Health Survey-2022 conducted by the Ministry of Health and Population, showed that at least four percent of children aged 12 to 23 months had received no vaccine.
The country had also witnessed repeated measles outbreaks in 2023. Nineteen districts of six provinces -- Koshi, Madhesh, Bagmati, Lumbini, Karnali, and Sudurpaschim -- witnessed measles outbreaks in 2023. At least one child died, and 1,300 others were infected with the deadly virus at the time.
Most districts that saw measles outbreaks in 2023 had been declared fully immunised before the outbreaks. Health officials from the disease-hit districts admitted that gaps in vaccination were exposed only after the outbreaks occurred.
To address the resurgence of vaccine-preventable diseases, health authorities launched repeated nationwide campaigns and administered vaccines to the children who had not received or completed all required doses.
"The new report shows our progress on immunisation, but our job has not finished," said Gautam. "New challenges including financing have emerged. We have dealt with existing challenges and are working to address emerging ones."
Immunisation experts in Nepal also said that funding crunch poses a serious threat to Nepal's immunisation programme. At present the government provides only 42 percent of the total immunisation budget, meaning that the remaining 58 percent comes from donor agencies.
"We all know that external help is diminishing," said Dr Shyam Raj Upreti, an immunisation expert. "The government has to increase its own investment to protect the immunisation programme."
Upreti said that the reduction in the number of zero-dose children by 50 percent also means that Nepal has yet to identify the remaining 50 percent. Nepal's own goal is to administer all children with routine antigens.
Childhood immunisation is the number one priority of the government, under which 13 types of vaccines are administered free of cost against a range of diseases, including measles-rubella, pneumonia, tuberculosis, diphtheria, pertussis, tetanus, hepatitis B, rotavirus, Japanese encephalitis and typhoid.
Experts say floating populations, scattered slums, working-class people, internal and external migration, lack of awareness and lack of awareness continue to pose challenges to immunisation programmes.