Immunization: How it started, how it's going – what we’ve achieved through 50 years of vaccination programmes

Immunization is one of the most effective health interventions we can make.

Every year vaccination programmes save millions of lives. They have helped eradicate diseases like smallpox – a deadly virus that has killed hundreds of millions of people. They were key to turning the tide of infections during the COVID-19 pandemic. And day-to-day they are protecting vulnerable babies and children from diseases like measles, meningitis and tuberculosis.

The benefits extend beyond individual health as well. By preventing the spread of infectious diseases, vaccines reduce the burden on healthcare systems, lower healthcare costs, and enhance productivity by averting illness-related absenteeism. Furthermore, immunization contributes to socioeconomic development by preserving human capital and promoting economic stability, particularly in resource-limited settings where disease outbreaks can have devastating consequences.

It’s been 50 years since the launch of the World Health Organization’s (WHO) Expanded Programme on Immunization (EPI) – a drive to provide universal access to life-saving vaccines for children worldwide – and this year’s World Immunization Week will recognize the collective efforts behind it.

A lot has changed since the EPI was launched in 1974. Today, every country has a national immunization programme and many diseases have become far less common and deadly than they once were. But, in recent years, progress on immunization has slipped. Millions of children are missing out on life-saving vaccinations because of growing conflicts, economic downturns and vaccine hesitancy.

So now is an opportune time to review what we have achieved in the past 50 years, and what more we can do to ensure that people do not die from vaccine-preventable diseases.

The WHO describes the eradication of smallpox as a “monumental triumph in the history of immunization” – and with good reason. The decline in smallpox deaths in the 20th century alone is extraordinary. Between 1900 and its eradication in 1980, the disease is estimated to have killed more than 300 million people.

A vaccine against the highly infectious variola virus that causes the disease was first discovered in 1796. In the following decades, several countries introduced mandatory vaccination policies. Although, at the turn of the century, the disease was still endemic in many countries, by the time the WHO's Intensified Smallpox Eradication Program was launched in 1966 it had been all but eliminated in Europe, North America and Australia. Coordinated programmes helped extinguish infections entirely by 1980.

We are now on the verge of eradicating polio, having first developed a vaccine against it in 1955. As a result of mass vaccination programmes in countries including India and Pakistan, cases of wild polio have decreased by 99% since 1988 when the World Health Assembly adopted a resolution to end the disease.

The EPI was initially focused on six childhood diseases. This list has now expanded to include 13 universally recommended vaccines and an additional 17 depending on context.

The list of vaccine-preventable diseases continues to grow and malaria is a recent notable addition to it. After successful trials in Ghana, Malawi and Kenya in 2019, the first malaria vaccine was recommended for use by the WHO in 2021. There are now two approved malaria vaccines the WHO recommends using to prevent malaria in endemic areas.

Millions of children have been reached through vaccination programmes and deaths from the disease in young children have been cut by 13%. With malaria remaining one of the leading causes of child mortality, reaching more people with these life-saving vaccines is a top priority.

Another crucial vaccine breakthrough has been the development of a vaccine for the human papillomavirus (HPV). It is responsible for the majority of cervical cancers, which are the fourth most common cancers in women. The vaccines also protect against other cancers including vaginal and anal.

Around 125 countries have introduced HPV vaccines since they were first licensed in 2006, and there are efforts to encourage other countries to introduce them into their routine immunization programmes.

This year, Nigeria became the first country in the world to roll out a new vaccine for meningitis, which protects people against five strains of the meningococcus bacteria. It is one of 26 countries in Africa where meningitis is hyper-endemic and last year the number of meningitis cases in Africa jumped by half.

Away from childhood immunization programmes, mass and targeted immunization interventions have also been crucial to curbing infections and deaths from several other diseases.

Ebola outbreaks, for example, can now be more quickly and effectively controlled by vaccinating those most at risk through “ring vaccination” strategies. The disease is relatively rare and unpredictable but also has a high death toll associated with it. A global stockpile of ebola vaccines has been established to help improve the response in the face of an outbreak.

The COVID-19 pandemic is another example of where rapid development of vaccines allowed the outbreak to be downgraded from one of global concern by limiting the spread and severity of the illness.

Through human ingenuity we can now prevent – and possibly end altogether – some of the world’s most deadly diseases. However, a challenge remains in ensuring these life-saving interventions are universally accessible.

Initiatives like the World Economic Forum’s Regionalized Vaccine Manufacturing Collaborative are vital to expanding vaccine production across the globe and preventing vaccine disparity across regions. By combining forces governments, pharmaceutical companies and investors can help prevent future pandemics and accelerate vaccine innovation.

These collaborations are also crucial to supporting the development and targeted funding needed to develop vaccines for the diseases we don’t yet have covered.

And, despite the overwhelming evidence supporting the safety and efficacy of vaccines, misinformation and misconceptions persist, leading to vaccine hesitancy and reluctance. Addressing these misconceptions requires comprehensive public health campaigns that prioritize education, transparency, and trust-building. Healthcare providers, policymakers, and community leaders play crucial roles in dispelling myths, providing accurate information, and fostering vaccine confidence among the population.