Vaccinations have greatly reduced the prevalence of diseases and continue to be important for global health today. The low price of vaccines have made them especially attractive as a way to improve global health and vaccines reached billions of people around the world. All countries implement some kind of routine childhood vaccination program. For governments, non-governmental organisations (NGOs), and public health institutions there are clear benefits. The public health benefits are why some government pay all or part of the costs of vaccinations in national vaccination schedules. Similarly international organisations such as the World Health Organization (WHO) have initiated vaccination programs and more recently the public-private partnership Gavi (the Vaccine Alliance), established in 2000 aims to increase vaccination in poor countries with a donation of $1.5 billion from the Bill and Melinda Gates Foundation.
Note: There is a technical difference between vaccination and immunisation: “Vaccination means having a vaccine – that is actually getting the injection, or nasal spray or oral vaccine. Immunisation means both receiving a vaccine and then becoming immune to a disease”. However both terms are often used interchangeably across the academic literature and in media reporting and we will follow this convention in the post.
# Empirical View
# The history of vaccine innovation
Vaccine innovation has followed both scientific and political-economic developments. Bacterial culture techniques, saw the development in the early 1900s of bacterial vaccines for diphtheria, tetanus, and pertussis. The first and second world wars also prompted combined efforts by universities, government, and private companies. By the 1950s viral tissue culture techniques resulted in vaccines against polio, measles, mumps, rubella, and varicella (chickenpox). New technologies in molecular biology and advanced chemistry techniques have most recently led to vaccines against hepatitis B, flu, pneumococcus.
For some diseases it has been a relatively short timespan between when the infectious agent was linked to the disease and a vaccine was developed. The quickest was 10 years for measles, with the agent linked to the disease in 1953 and the vaccine licensed in the U.S. in 1963. Malaria is proving harder as it has been over 135 years since the agent was linked to the disease. A vaccine is in development –RTS,S is undergoing pilot trials in select countries after being approved by European regulators in 2015.
Vaccine innovation has both followed scientific and political-economic developments. Bacterial culture techniques, saw the development in the early 1900s of bacterial vaccines for diphtheria, tetanus, and pertussis.1 The first and second world wars also prompted combined efforts by universities, government, and private companies.2 By the 1950s viral tissue culture techniques resulted in vaccines against polio, measles, mumps, rubella, and varicella (chickenpox). New technologies in molecular biology and advanced chemistry techniques have most recently led to vaccines against hepatitis B, flu, pneumococcus (causing meningitis).3
Diseases prevented through immunization
The most common and serious vaccine-preventable diseases tracked by the World Health Organization (WHO) are the following:4
- Diptheria, tetanus, and pertussis (DTP3): All are bacterial diseases. Diptheria primarily infects the throat and upper airways and is fatal in 5 – 10% of cases. Tetanus is not passed person-to-person but through spores of a bacteria living in soil and animal intestinal tracts. Pertussis is a highly contagious disease of the respiratory tract. Children who contract pertussis tend to have coughing spells that last four to eight weeks. Vaccinating health workers and pregnant women is the most effective strategy for preventing disease in infants too young to be vaccinated.
- Haemophilus influenzae type b (Hib): is an infection that causes meningitis and pneumonia transmitted through the respiratory tract from infected to susceptible individuals.
- Hepatitis B (hepb): is a highly contagious viral infection that attacks the liver and is transmitted through contact with the blood or other body fluids of an infected person. It is estimated that about 780,000 people die each year due to consequences of hepatitis B. WHO recommends that all infants should receive their first dose of vaccine as soon as possible after birth, preferably within 24 hours.
- Poliomyelitis (Pol3): is a highly infectious viral disease. Once the poliovirus invades the nervous system it can cause irreversible paralysis in a matter of hours. No cure exists for polio, only treatment to alleviate symptoms.
- Measles, mumps, and rubella (MMR): All are viral diseases. Measles is a highly contagious major killer of young children globally, despite a safe and effective vaccine being available. Mumps infection occurs via direct human contact or by airborne droplets. It causes painful swelling at the side of the face under the ears (the parotid glands), fever, headache and muscle aches. Rubella 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.
- Meningococcal meningitis (meningitis ACWY): Can cause severe brain damage and is often deadly. Transmitted through contact with respiratory droplets or secretions.
- Tuberculosis (TB): is a bacterial disease transmitted by people infected with pulmonary (lung) TB. The BCG vaccination is only partially effective providing some protection against severe forms of TB in children but is unreliable against adult pulmonary TB.
- Yellow fever (YF): is a viral disease transmitted by infected mosquitoes. There are 42 countries and territories at risk for yellow fever in Africa and the Americas. In these 42 countries and territories, coverage is estimated at 45%.
# Progress against vaccine-preventable diseases over the long run
# Reduction of cases and deaths of vaccine-preventable diseases in the United States after the introduction of the vaccine
This table requires further explanation as, for example with measles case-fatality rates were falling in high income countries such as the US between 1900 and 1960. Improved living conditions and medical advancements meant that measles was less likely to be fatal, however disease incidence was virtually unchanged until after the measles vaccine was introduced.5
# Vaccine supply
Many vaccines are only provided by one or two suppliers. For newer vaccines there are less suppliers due to the high investment needed to develop a vaccine and also having patents attached but this can also lead to high profits. Prevnar, the brand name for the pneumococcal vaccine (PCV) was hugely profitable for the pharmaceutal company Wyeth (purchased by Pfizer in 2009), with sales in 2005 of $1.5 billion.
The WHO notes the more suppliers the more competitive environment there is to drive prices down.6 Only one vaccine for tetanus and diphtheria (td) in an adult/adolescent formulation has a large number of suppliers at 13 and 7 for td in the paediatric formation. Supply contraints have caused problems for country access to vaccination. Concerns about the supply of vaccines in an epidemic or pandemic have been raised. Supply of yellow fever vaccine was limited for the outbreak in Angola in 2016 leading to the recommendation of a fractional dose to extend existing supplies. Romania experienced a situation of parallel vaccine exports in 2016 where more vaccines were exported than was supplied to meet country needs.
# The cost of vaccines
Some vaccines for the same disease are more expensive. For example, the pertussis vaccine either comes in two versions: whole cell (wP) where the whole pertussis organism is contained or acellular (aP) where part of the pertussis organism is contained. The pertussis vaccine is combined with diptheira and tetanus to produce wither a DTwP or DTaP vaccine. DTaP is more expensive sometimes called ‘the painless vaccine’ because it cause less of a local reaction and pain but should not be given to children over the age of seven. However, DTwP has been shown to prevent the transmission and spread of disease to unvaccinated people and to thos with weak immunity.
# Vaccination coverage and decline of the disease burden globally
We provide detail on three vaccinations: DTP3, measles, and polio. These diseases were the original one targeted by the WHO for their Expanded Program on Immunization (EPI).
# Diphtheria, Tetanus, and Pertussis (DTP3) – global vaccination coverage and decline of the disease burden
Global increase in vaccination coverage and the global decline of DTP3
The WHO reports that about 86% of infants worldwide (116.5 million infants) received 3 doses of diphtheria-tetanus-pertussis (DTP3) vaccine. This includes 130 countries had reached at least 90% coverage of DTP3 vaccine.7
Vaccination Coverage against DTP3
The chart below shows the progress over time of DTP3 immunization coverage for children around the world. By clicking on any country you can see the change in that country over time.
Ukraine stands out as having particularly low DTP vaccination rates in 2015 of 23%, falling from 98% in 1999. Only Equatorial Guinea has lower rates at 16%.
# Measles – global vaccination coverage and decline of measles
Global increase in vaccination coverage and the global decline of measles
The WHO estimate that by the end of 2016, 85% of children had received one dose of measles vaccine by their second birthday, 164 countries had included a second dose as part of routine immunization and 64% of children received two doses of measles vaccine according to national immunization schedules.8 Two doses are needed for a higher level of protection.
Vaccination Coverage against measles
The world map shows the share of children vaccinated against measles.
You can switch to the ‘chart’ view to see the global coverage against vaccines. The measles vaccine was developed in 1963. In 1983 – the first year for which global data is available – only every second child was vaccinated against measles. In the latest data this share has increased to 85% globally.
Global decline of measles
Country by country you can see the change over time in this visualization here.
# Polio – global vaccination coverage and decline of polio
Global increase in vaccination coverage and the global decline of polio
Vaccination Coverage against polio
# Successes of vaccination
People in richer countries continue to benefit from the application of vaccinations. But the benefits might possibly be forgotten just because the diseases have lost their threat after the introduction of the vaccines.
To see how we are benefiting from vaccinations it is necessary to compare the suffering before and after the introduction of the vaccine. This is what Roush and Murphy did for the US, and we have visualized the reduction in mortality for vaccine-preventable diseases in the following graph (and also reprinted a table with more results just below the graph). The graph shows that the reduction in mortality is mostly 100% across multiple vaccine-preventable diseases. Shown here is Smallpox, which has now been eradicated and is the only human disease to ever have been eradicated through vaccination. Rinderpest is the other disease that affects cattle. There are diseases nearing eradication, such as Polio.
The same data can be viewed in a table here. (Note: Acute and paralytic polio are shown separately, and the same for Rubella and Congenital Rubella Syndrome).
# People do not know how well we actually do in global vaccination
The Gapminder Ignorance Project studied how wrong or right people are informed about global development.
One question asked was:
How many of the world’s 1-year-old children today have been vaccinated against some disease?
The answer is A. 80% but only 22% of the American public got this question right in 2013. They tended to be more pessimistic picking the lower percentages. Mass vaccination coverage expanded greatly through the Expanded Programme on Immunization (EPI). The EPI was initiated by the WHO in 1977 and by 2010 an estimated 85% of children under the age of one have been immmunized with at least three doses of the vaccine DPT3.10
The goal was universal immunization for and diseases. The first diseases targeted by the EPI were diphtheria, whooping cough, tetanus, measles, poliomyelitis and tuberculosis.
Visual: Barchart from Rosling’s Ignorance project
# Correlates, Determinants, and Consequences
How vaccines work
Vaccines typically cause acquired immunity via some agent inside the vaccine that resembles the disease-causing microorganism. The agent can be made of killed or weakened forms of the microorganism, its toxins or its surface proteins. More information about vaccines in general can be found at the Wikipedia page on vaccines.
Herd Immunity and why to care about broad vaccination coverage
There is a collective social benefit in more people vaccinating. The greater numbers who vaccinate the more people who cannot be vaccinated can be protected. Herd immunity provides a protective barrier, especially for those who cannot be vaccinated. These include vulnerable groups such babies too young to be vaccinated or immune-compromised children who are the first potential victims of low vaccination. Herd immunity is a community protection that is produced when a high percentage of the population is vaccinated, such that it is difficult for infectious diseases that are contagious to spread.11
If vaccination coverage is high than disease transmission can be stopped.
|Disease||Transmission||Basic reproduction number||Herd Immunity Threshold|
When a person is immune to a disease they can act as a barrier to slow down or prevent the transmission of disease to other people. When the number of people in a population that are immune against a disease is reached, such that a disease no longer persists in the population, this is called the herd immunity threshold (HIT). Measles and pertussis are very contagious airborne diseases and so have the highest HIT rates that need to be reached and so a higher number of people vaccinated to stop transmission.
# Determining impact: Why do vaccine schedules differ and what is the effect of vaccination compared with better hygiene?
# The chickenpox example
Chickenpox (varicella) is an example of a vaccine that some countries adopt into their routine childhood vaccination schedules, while others do not. The question that follows is why there is a difference in opinion for introducing widespread uptake of a vaccine or not. Japan was one of the first countries to adopt universal chickenpox vaccination, followed by Australia, Canada, Germany, Qatar, Republic of Korea, Saudi Arabia, Taiwan, Uruguay, U.S., Italy (Sicily only) and Spain (Madrid only).13
Most European countries do not vaccinate against chickenpox, except for ‘at risk’ groups. A main reason is cost, with the supporting justifications that it is usually a mild disease and the concern that it could cause an increase the risk of chickenpox and shingles in adults for reasons explained in this article, with the benefit of less cases of shingles weighed against more cases of chickenpox. When extreme cases of chickenpox have occurred there have been calls for the vaccine to become available for free through the National Health Service in the UK.
Chickenpox can also help answer the question often raised of whether hygiene or vaccination has reduced rates of disease. Although both are important, a more recently adopted vaccination such as chickenpox can demonstrate the effects of vaccination in reducing the rate of disease after the importance of hygiene was discovered and became a preventative measure against disease. The chickenpox vaccine was introduced later than when hygiene practices became widespread. The impact on disease rates demonstrate it is not hygiene but vaccination that reduced chickenpox so dramatically in the US.
The Centers for Disease Control and Prevention in the US ran the Varicella Active Surveillance Project (VASP) from 1995 through to 2010 to monitor the impact of the varicella vaccination program in two states: Antelope Valley, California, West Philadelphia, Pennsylvania, and Travis County, Texas. The coverage of the vaccine in Los Angeles County, rose from 37.9% in 1997 to 95.1% in 2010 and in Philadelphia from 41.2% in 1997, to 94.6% in 2010 (one-dose vaccinations for children between 19 and 35 months of age). By 2010, varicella incidence declined 98% in Antelope Valley, California and West Philadelphia, Pennsylvania compared with 1995. Outbreaks and hospitalizations also decreased rapidly. From 1995 to 1998, hospitalization rates ranged from 2.2 to 3.3 per 100,000 population but by 2006-2010, this had declined to 0.2 per 100,000 in Antelope Valley and 0.5 per 100,000 in Philadelphia.
# People who are not vaccinating
# Impact of vaccine resistance and controversies on coverage and disease outbreaks
Anti-vaccination opposition is as old as mass vaccination itself. The original anti-vaccination organisation ‘Anti-compulsory Vaccination League’ was established in the UK in 1866 as a protest against smallpox vaccination mandates. In the late 1880s and 1900s opposition to vaccines in the U.S was organised through the ‘Anti-Vaccination League of America’ and the ‘American Medical Liberty League’ (Wolfe & Sharp, 2002). At this time resistance could be attributed to concern about the safety and efficacy of vaccines, which were an unregulated industry along with a dislike for the extension of state powers.
Since then, the view of vaccine resistance has been split between higher and lower income countries. In higher income countries controversies have been attributed to fear and uncertainty about the side effects. In the 1970s and 1980s the DPT vaccine was questioned in connection with permanent brain injury or encephalopathy but studies would show no connection. In the late 1990s and early 2000s MMR was connected with bowel symptoms and autism by a 1998 paper authored by Andrew Wakefield and others. The paper was later retracted by the journal (The Lancet) and Wakefield struck off the UK medical register after results were found to be fraudulent.
In lower income countries opposition has been connected to in the 1950s Channai (Madras) India with a push-back to nationalist and the will of outside post-colonial forces. Since 1988 polio cases have fallen by over 99%, from an estimated more than 350 000 cases to 37 reported cases in 2016.14 Three countries have never been able to stop the transmission of polio: Afghanistan, Nigeria and Pakistan. Jonathan Kennedy and Domna Michailidou explain some of the political dynamics behind the low vaccination rates in Nigeria and Pakistan.15 In Nigeria reflected political events where a majority Muslim population in the North feared the intervention of the newly appointed Christian majority government. In Pakistan Pashtun communities resist the expansion of the Pakistani state and Pakistani Taliban hostility comes from the fake hepatitis vaccination campaign led by the CIA to try to gather DNA to help find Osama Bin Laden.
In Afghanistan it appears traditional supply problems persist in a post-conflict country where it is: “Geographical barriers and functional challenges” that impact upon outreach and coverage capacity.16
Researchers at the Vaccine Confidence Project have begun to measure scepticism of vaccination to track public beliefs and attitudes to vaccination across countries.
Important for children https://ourworldindata.org/grapher/share-disagrees-vaccines-are-important-for-children-to-have
Religious belief https://ourworldindata.org/grapher/share-that-disagrees-vaccines-compatible-with-their-religious-beliefs
Safety vs coverage https://ourworldindata.org/grapher/perception-of-the-safety-of-vaccines-vs-vaccine-coverage
Effectiveness vs importance https://ourworldindata.org/grapher/confidence-in-the-effectiveness-of-vaccines-vs-perception-of-importance
# Does it work to make vaccinations compulsory?
Countries vary in whether vaccination is compulsory, required (according to specific mandates) or voluntary. Which policy is taken has depended much on historical legacy or recent outbreaks and anti-vaccination activity. Many Eastern European countries introduced compulsory vaccination during the communist era. Vaccination was previously compulsory in Romania for example and after a drop in vaccination rates the country is going through the process of reintroducing compulsory vaccination. The same is true for Italy and also France, which had compulsory vaccination for three diseases but increased this number to 11 in 2017 in response to a drop in rates.
The US has mandates for vaccination where vaccination is required to enter state school or daycare. An early case in the US paved the way for state jurisdiction to protect public health in light of personal liberty.17 Jacobson v. Massachusetts (1905) led to the Supreme Court ruling that states have the authority to require vaccination against smallpox during a smallpox epidemic. Since then the United States has had a history of school vaccination requirements. The compulsory school attendance law led to a huge increase in the number of children in public schools and an increased the risk of smallpox outbreaks.
Similarly in Australia two policies penalise parents for not vaccinating their children. The ‘No jab no play’ policy removed state-sponsored childcare. The 2016 ‘No jab no pay’ policy removes state welfare by not providing the universal ‘Family Allowance’ welfare payments for parents who are conscientious objectors of vaccination. Some countries where vaccination is voluntary had early pushback against vaccination, as with the UK and the Netherlands. In 1853 a law was passed in England and Wales requiring universal vaccination against smallpox but opposition from anti-vaccinationists led to laws being passed to allow for conscientious objection.18
For countries in Africa and South America where yellow fever is endemic or where the mosquito vector is present a certificate of proof of vaccination is required. Only then will the country issue a visa or upon entry to that country to prevent such importation of the disease (this is particularly if travellers come from, or have visited yellow fever endemic areas).19 In past centuries (17th to 19th), yellow fever was transported to North America and Europe, causing large outbreaks that disrupted economies, development and in some cases decimated populations. Throughout the 18th and 19th century, yellow fever was among the most feared diseases in the ports of the Old and New World. Only Saudi Arabia required the additional vaccinations of meningococcal disease and polio for pilgrims visiting Mecca.
The U.S. is one country where states decide on what exemptions are allowed for the mandate for children to receive vaccinations to access education and daycare. Exemptions are granted for medical reasons but many states also allow for philosophical, personal belief or religious exemptions. Only Mississippi, West Virginia, and California only allow for medical exemption. Californian immunization rates have increased following a new Senate Bill SB 277 in 2015 to remove non-medical exemptions to vaccination.
# Prosperity and vaccination coverage
Shown is the correlation of vaccine coverage against the level of prosperity of a country. The shown vaccine coverage against diphtheria, pertussis (whooping cough), and tetanus is a good marker of strength in a country’s immunization programmes since several administrations are required. Rich countries have vaccination coverage rates of more than 90%.
Countries in which a large share of the population is living in extreme poverty often – but not always – have lower immunization rates, as this chart shows.
# Measurement, Data Quality & Definition
# Calculating coverage
The coverage is calculated as the proportion of persons in a target age group who received a vaccine dose. Dates of vaccination are either taken from a child’s home-based record, recorded based on caregiver recall or from health facility records.
While appearing straightforward enough, the methodological problems of household survey respondent data on vaccination has been well documented. Questions have arisen about how accurately parent can recall child immunisation history and the limitations of phone calls to collect data.
Even accurately estimating target populations in low-income settings can be difficult and discrepancies have been found when comparing country-reported figures to independent surveys.20
Furthermore, childhood vaccinations are rarely considered altogether. The vaccination ‘DTP3’, which is Diptheria, Tuberculosis and Pertussis, tends to be the vaccination most often used as a marker of strength in a country’s immunisation programmes, since three administrations of the vaccination are required. (Other vaccines measured by the WHO and UNICEF are HepB3, Hib3, MCV and PAB).
# National and subnational coverage
National coverage rates are what is focused upon, but even when national coverage are high, subnational coverage can reveal inequities, which is why the WHO and UNICEF are increasing efforts to gather high quality subnational coverage data.21
In 2015 coverage estimates at the district level were only reported for 158 of the 194 WHO Member States. National data only provides part of the picture of immunization coverage. Different levels of coverage data, including at sub-national or district level is useful for gaining an understanding of where there might be clusters of under- or un-vaccinated children.
# Data Sources
# World Health Organization – Immunization surveillance, assessment and monitoring
- Data: Immunization coverage, system indicators and schedule, and disease incidence
- Geographical coverage: WHO member nations
- Time span: 1980-2014 for many countries
- Available at: Online here
- Data: Percent of one-year-olds immunized
- Geographical coverage: UN member nations
- Time span: 1980-2014 for many countries
- Available at: Online from UNICEF here. Also available via Gapminder here (search “vaccine” to find the data).