Childhood vaccination is one of the most cost-effective and safe health policy interventions to reduce disease burden of the population, preventing around 4.4 million deaths every year worldwide (Carter et al., 2023[1]). However, in 2023 there were 14.5 million children missing out on any vaccination globally (WHO, 2024[2]).
All countries and territories in Asia-Pacific have established vaccination programmes including a minimum number of routine vaccines (i.e. against polio, diphtheria, tetanus, pertussis, measles); additional vaccines (i.e. against pneumococcus, rotavirus, Japanese encephalitis and human papilloma virus) are included at national or subnational level based on local morbidity, mortality and cost-effectiveness analysis.
Diphtheria, tetanus toxoid and pertussis, measles and hepatitis B vaccines are taken as example here as they represent, in timing and frequency of vaccination, the full spectrum of organisational challenges related to routine vaccination for children.
Pertussis, known as whooping cough, is a respiratory infection caused by bacteria. Three doses of pertussis vaccine, together with diphtheria and tetanus toxoid reduces the risk of their infections and severe symptoms among infants. WHO recommends the first dose at 6 weeks of age, subsequent doses at age 10‑14 weeks and age 14‑18 weeks, as well as a booster dose, preferably at age 2 years (WHO, 2024[3]).
Measles is a highly contagious viral disease. The measles vaccine is not only safe and effective, but also inexpensive. Although vaccination prevented about 57 million deaths between 2000 and 2022 globally, measles is still common (WHO, 2024[4]). In the WHO Western Pacific Region, measles incidence increased by more than 2.5‑fold between 2022 and 2023 (WHO, 2024[5]). This is likely be due to the decline in measles vaccination coverage during the COVID‑19 pandemic, as well as the increased population movements and improved disease surveillance after the pandemic (WHO, 2024[5]), pointing to the importance of vaccination against measles outbreaks. WHO recommends two doses of measles vaccine, alone or in combined with in rubella, mumps, and/or varicella in national childhood immunisation programmes (WHO, 2024[6]).
With regards to hepatitis B, vaccination is considered effective in preventing infection and its chronic consequences, such as cirrhosis and liver cancer. Yet, in 2022, hepatitis B resulted in approximately 1.1 million deaths. Globally, WHO Western Pacific Region is the region with the most infections in the world, with 97 million people chronically infected, and in WHO South-East Asia Region, 61 million people were infected. Recommended hepatitis B vaccination is first dose as soon as possible after birth, ideally within 24 hours, followed by two or three doses at least four weeks apart (WHO, 2024[7]).
In 2023, the overall vaccination of children against pertussis (provided through combined vaccines containing diphtheria and tetanus), measles and hepatitis B was high in most Asia-Pacific countries. In most high- and upper-middle-income Asia-Pacific countries, almost all children received the recommended DTP3, measles and Hepatitis B vaccination, and most high-income countries met the WHO’s minimum threshold of 95% to avoid vaccine‑preventable diseases outbreaks. On the contrary, the average vaccination rate for these diseases was around 75% in lower-middle- and low-income Asia-Pacific countries, which is insufficient to ensure interruption of disease transmission and protection of the whole population (Figure 7.1, Figure 7.2 and Figure 7.3).
Vaccination coverage rates for DTP3, measles and hepatitis B were mostly similar for each Asia-Pacific country. Brunei Darussalam and Sri Lanka had the highest rate in Asia-Pacific at 99% against all of them. However, in DPRK and Papua New Guinea, less than one in two children were vaccinated with all three (Figure 7.1, Figure 7.2 and Figure 7.3). While many countries and territories in Asia-Pacific have maintained high vaccination rates during the pandemic, some lower-middle- and low-income countries have seen a decline in childhood vaccination rates in recent years. In DPRK, the vaccination rates for DTP3, measles and Hepatitis B have declined substantially since 2019, from over 97% to 16% in 2023. In Myanmar, these rates decreased sharply from 80‑94% in 2020 to 37‑42% in 2021, due to the political situation, although it has increased again since 2021 (Poe et al., 2024[8]; WHO, 2024[9]).
