Immunization coverage

Overview

While immunization is one of the most successful public health interventions, coverage has plateaued over the last decade. The COVID-19 pandemic and associated disruptions have strained health systems, with 25 million children missing out on vaccination in 2021, 5.9 million more than in 2019 and the highest number since 2009.

During 2021, about 81% of infants worldwide (105 million infants) received 3 doses of diphtheria-tetanus-pertussis (DTP3) vaccine, protecting them against infectious diseases that can cause serious illness and disability or be fatal.

Twenty five vaccine introductions were reported in 2021 (not including COVID-19 vaccine introductions). Although this is an increase from 17 introductions in 2020, it is well below the number of introductions of any year in the past two decades prior to 2020. This slowdown is likely to continue as countries focus on ongoing efforts to control the COVID-19 pandemic.

Global immunization coverage 2021

A summary of global vaccination coverage in 2021 follows.

Haemophilus influenzae type b (Hib) causes meningitis and pneumonia. Hib vaccine had been introduced in 192 Member States by the end of 2021. Global coverage with 3 doses of Hib vaccine is estimated at 71%. There is great variation between regions. The WHO Eastern Mediterranean Region and South-East Asia Region are each estimated to have 82% coverage, while it is only 29% in the WHO Western Pacific Region.

Hepatitis B is a viral infection that attacks the liver. Hepatitis B vaccine for infants had been introduced nationwide in 190 Member States by the end of 2021. Global coverage with 3 doses of hepatitis B vaccine is estimated at 80%. In addition, 111 Member States introduced nationwide 1 dose of hepatitis B vaccine to newborns within the first 24 hours of life. Global coverage is 42% and is as high as 78% in the WHO Western Pacific Region, while it is only estimated to be at 17% in the WHO African Region.

 Human papillomavirus (HPV) is the most common viral infection of the reproductive tract and can cause cervical cancer in women, other types of cancer, and genital warts in both men and women. Including 5 new introductions, 116 Member States have introduced HPV vaccine by the end of 2021. Since many large countries have not yet introduced the vaccine and vaccine coverage decreased in 2021 in many countries, global coverage with the first dose of HPV among girls is now estimated at 15%. This is a proportionally large reduction from 20% in 2019. 

Meningitis A is  an infection that is often deadly and leaves 1 in 5 affected individuals with long-term devastating sequelae. Before the introduction of MenAfriVac in 2010 – a revolutionary vaccine – meningitis serogroup A accounted for 80–85% of meningitis epidemics in the African meningitis belt. By the end of 2021, 350 million people in 24 out of the 26 countries in the meningitis belt had been vaccinated with MenAfriVac through campaigns. Thirteen countries had included MenAfriVac in their routine immunization schedule by 2021..

Measles is a highly contagious disease caused by a virus, which usually results in a high fever and rash, and can lead to blindness, encephalitis or death. By the end of 2021, 81% of children had received 1 dose of measles-containing vaccine by their second birthday, and 183 Member States had included a second dose as part of routine immunization and 71% of children received 2 doses of measles vaccine according to national immunization schedules.

Mumps is a highly contagious virus that causes painful swelling at the side of the face under the ears (the parotid glands), fever, headache and muscle aches. It can lead to viral meningitis. Mumps vaccine had been introduced nationwide in 123 Member States by the end of 2021.

Pneumococcal diseases include pneumonia, meningitis and febrile bacteraemia, as well as otitis media, sinusitis and bronchitis. Pneumococcal vaccine had been introduced in 154 Member States by the end of 2021, including 2 in some parts of the country, and global third dose coverage was estimated at 51%. There is great variation between regions. The WHO European Region is estimated to have 82% coverage, while it is only 19% in the WHO Western Pacific Region.

Polio is a highly infectious viral disease that can cause irreversible paralysis. In 2021, 80% of infants around the world received 3 doses of polio vaccine. In 2021, the coverage of infants receiving their first dose of inactivated polio vaccine (IPV) in countries that are still using oral polio vaccine (OPV) is estimated at 79%. Targeted for global eradication, polio has been stopped in all countries except for Afghanistan and Pakistan. Until poliovirus transmission is interrupted in these countries, all countries remain at risk of importation of polio, especially vulnerable countries with weak public health and immunization services and travel or trade links to endemic countries.

Rotaviruses are the most common cause of severe diarrhoeal disease in young children throughout the world. Rotavirus vaccine was introduced in 118 countries by the end of 2021, including 2 in some parts of the country. Global coverage was estimated at 49%.

Rubella is a viral disease which is usually mild in children, but infection during early pregnancy may cause fetal death or congenital rubella syndrome, which can lead to defects of the brain, heart, eyes and ears. Rubella vaccine was introduced nationwide in 173 Member States by the end of 2021, and global coverage was estimated at 66%.

Tetanus is caused by a bacterium which grows in the absence of oxygen, for example in dirty wounds or the umbilical cord if it is not kept clean. The spores of C. tetani are present in the environment irrespective of geographical location. It produces a toxin which can cause serious complications or death. Maternal and neonatal tetanus persist as public health problems in 12 countries, mainly in Africa and Asia.

Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes. As of 2021, yellow fever vaccine had been introduced in routine infant immunization programmes in 36 of the 40 countries and territories at risk for yellow fever in Africa and the Americas. In these 40 countries and territories, coverage is estimated at 47%.

Key challenges

In 2021, 18.2 million infants did not receive an initial dose of DTP vaccine, pointing to a lack of access to immunization and other health services, and an additional 6.8 million are partially vaccinated. Of the 25 million, more than 60% of these children live in 10 countries: Angola, Brazil, the Democratic Republic of the Congo, Ethiopia, India, Indonesia, Myanmar, Nigeria, Pakistan and the Philippines.

Monitoring data at subnational levels is critical to helping countries prioritize and tailor vaccination strategies and operational plans to address immunization gaps and reach every person with life-saving vaccines.

WHO response 

WHO is working with countries and partners to improve global vaccination coverage, including through these initiatives adopted by the World Health Assembly in August 2020.

Immunization Agenda 2030

IA2030 sets an ambitious, overarching global vision and strategy for vaccines and immunization for the decade 2021–2030. It was co-created with thousands of contributions from countries and organizations around the world. It draws on lessons from the past decade and acknowledges continuing and new challenges posed by infectious diseases (e.g. Ebola, COVID-19).

 The strategy has been designed to respond to the interests of every country and intends to inspire and align the activities of community, national, regional and global stakeholders towards achieving a world where everyone, everywhere fully benefits from vaccines for good health and well-being. IA2030 is operationalized through regional and national strategies and mechanisms to ensure ownership and accountability and a monitoring and evaluation framework to guide country implementation.

The global strategy towards eliminating cervical cancer as a public health problem

In 2020, the World Health Assembly adopted the global strategy towards eliminating cervical cancer.  In this strategy, the first of the 3 pillars requires the introduction of the HPV vaccine in all countries and has set a target of reaching 90% coverage. With introduction currently in 57% of Member States, large investments towards introduction in low and middle-income countries will be required in the next 10 years as well as programme improvements to reach the 90% coverage targets in low and high-income settings alike will be required to reach the 2030 targets.