Viet Nam launched its Expanded Programme on Immunisation in 1981, aiming to make vaccines available to children in every region. Over more than four decades, the programme has achieved several major milestones: eradicating smallpox and polio in 2000, eliminating neonatal tetanus in 2005, and significantly reducing the incidence of many infectious diseases, including measles, diphtheria, whooping cough and Japanese encephalitis.
A missed dose can leave a gap in protection
The COVID-19 pandemic disrupted routine immunisation, leaving some children without their scheduled vaccinations. In the years that followed, the health sector focused on restoring coverage, particularly in hard-to-reach areas, and these efforts have yielded clear results.
According to the World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF), Viet Nam achieved 99% coverage for the first dose of the diphtheria-tetanus-pertussis (DTP) vaccine in 2024, up from 80% in 2023. The proportion of children who received all three DTP doses reached 97%, while coverage of the first measles dose rose from 82% to 98%. Notably, the number of zero-dose children – those who had not received any routine vaccine – fell from about 274,000 in 2023 to 13,000 in 2024.
These figures show that the immunisation system has made a strong recovery from the pandemic. However, high coverage does not mean that immunity gaps have disappeared.
Immunisation schedules are set around specific ages and intervals so that children develop immunity as early as possible. In practice, a child may have to postpone a vaccination because of illness. Parents may then become preoccupied, forget the appointment or assume that a slight delay in one dose does not matter. In other cases, families may be swayed by inaccurate information about vaccines circulating on social media.
According to Dr Nguyen Quoc Thai, Deputy Head of the General Infectious Diseases Department at the Institute of Tropical Medicine of Bach Mai Hospital, immunity gaps can arise for several reasons, including families’ awareness, the reliability of vaccine supplies and the ability of immunisation services to respond to cases requiring special counselling and monitoring.
If a missed dose is not made up, the child remains unprotected for longer. When this happens to many children, the risk extends beyond the individual to the whole community.
A case in Ha Noi illustrates the devastating consequences of missed vaccinations. A 44-month-old girl in Nam Tu Liem died of measles in March 2025. According to the Ha Noi Centre for Disease Control (CDC Ha Noi), the child had never received a measles vaccine. She fell ill on March 10 and subsequently developed severe disease, with pneumonia and multiple organ failure.
Despite intensive treatment at the National Children’s Hospital, she could not be saved. Tragically, local authorities had urged the family on several occasions to have the child vaccinated, but the family had not done so.
This case also shows that immunity gaps are not an abstract concept confined to statistical tables. For an unprotected child, such a gap can become a real threat when the virus circulates in the community.
That said, vaccines are not an absolute shield: vaccinated people can still contract a disease. One of their most important benefits is that they reduce the risk of severe illness. For example, CDC Ha Noi said children vaccinated against whooping cough can still contract the disease, but their symptoms are generally milder and they recover more quickly than unvaccinated children.
Vaccines therefore reduce the risk of severe illness for individuals, while high vaccination coverage limits the chances of viruses continuing to spread in the community.
Associate Professor Dr Pham Quang Thai, Head of the Northern Regional Office of the Expanded Programme on Immunisation at the National Institute of Hygiene and Epidemiology, said the continued outbreaks are linked to community immunity that has not always been strong enough, with some people unvaccinated or only partially vaccinated.
Community immunity is therefore not an achievement that can be secured once and for all. It must be continually reinforced through timely vaccination, completion of the required doses and prompt catch-up vaccination for those who have missed appointments.
Broader policies, improved access
Maintaining high vaccination coverage depends in part on ensuring that vaccines are available and that people can obtain them at an affordable price.
Under the 2026–2028 immunisation plan, the Expanded Programme on Immunisation provides vaccines against 13 diseases for children and pregnant women, covering hepatitis B, tuberculosis, diphtheria, whooping cough, tetanus, polio, Haemophilus influenzae type b (Hib), measles, rubella, Japanese encephalitis, rotavirus, pneumococcal disease and human papillomavirus (HPV).
Rotavirus vaccines have been provided free of charge nationwide since 2026, while pneumococcal and HPV vaccines are being introduced into the programme under a phased roadmap. For HPV vaccination, the initial phase targets 12-year-old girls in selected localities.
The Ministry of Health has also designated 14 diseases for which vaccines and biological products must be used under the Expanded Programme on Immunisation, and set out rules for the management of vaccine recipients, routine immunisation, catch-up vaccination, campaign-based vaccination and outbreak-response vaccination.
The challenge now is not simply to deliver vaccines to vaccination sites but, more importantly, to track who has been vaccinated, who has missed a dose and who needs catch-up vaccination, and to ensure that hard-to-reach groups are not left outside the system.
The target for 2030 is to maintain coverage of at least 95% for vaccines under the programme. This remains challenging, given that Viet Nam still has geographically remote areas, a mobile population and groups with limited access to accurate health information.
Sustainable vaccine coverage also depends on reliable supplies. If vaccines are in short supply or supplies are erratic, people may have to postpone vaccinations even when they are willing to be vaccinated.
Viet Nam has been developing its domestic vaccine manufacturing capacity for many years. Local research and manufacturing facilities have helped supply a number of vaccines for the Expanded Programme on Immunisation and continue to invest in new technologies.
The programme to ensure vaccine supplies through 2030 aims for Viet Nam to master the technologies to manufacture 15 types of vaccines, with domestically produced vaccines meeting international standards.
This approach matters not only for technological development but also for health security. The pandemic showed that excessive dependence on external supplies can disrupt immunisation when international markets are volatile.
In addition to established domestic manufacturers, the VNVC Vaccine and Biological Products Factory in Tay Ninh broke ground in May 2025 under a technology-transfer partnership with a French company. The factory is expected to begin operations in late 2027 and produce its first vaccines in 2028.
These developments show that Viet Nam’s vaccine strategy rests on two pillars: expanding access and strengthening self-reliance in vaccine supply.
According to Associate Professor Dr Tran Dac Phu, a leading epidemiologist in Viet Nam, vaccines deliver their full benefits only when administered at the right time.
Maintaining high coverage therefore starts with practical steps: parents should keep track of their children’s vaccination schedules, contact healthcare facilities promptly for advice on catch-up vaccination if a dose is missed, and seek information from official sources.
“The health sector’s responsibility is to ensure that vaccines are available in sufficient quantities and are safe and convenient to access; to strengthen systems for monitoring, reminders and catch-up vaccination; and to provide thorough counselling for cases requiring special monitoring,” Phu said.
He added: “More broadly, local authorities need to ensure adequate resources and access in disadvantaged areas; the health sector must continue to monitor vaccine safety and detect immunity gaps early; and manufacturers must invest in vaccine technology and quality.”
A single vaccination protects one person first and foremost, but when millions of people are protected, that protection becomes a safeguard for the entire community.
