The biggest immunisation decline in a generation shows why we need to get ahead of escalating infectious diseases

25 million children hadn’t received essential vaccinations in 2021, according to the latest data from the World Health Organization (WHO) and UNICEF. That’s 2 million more than in 2020 and 6 million more than 2019.

In the Ampasimandrorona district, Madagascar, a doctor speaks to the grandmother and mother of twins about the importance of vaccinating the infants.

In the Ampasimandrorona district, Madagascar, Dr Koné Foussen speaks to the grandmother and mother of twins about the importance of vaccinating the infants.


WHO / Henitsoa Rafalia

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Charlie Weller

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The biggest immunisation decline in a generation shows why we need to get ahead of escalating infectious diseases
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The data for immunisation coverage in 2020 and now 2021 show in sobering detail what happens when an infectious disease like Covid-19 is not controlled or contained and escalates out of control on a global scale. But it also points to cracks and challenges that existed before the pandemic and how these issues get compounded.

This is an important reminder that we must shift from responding to outbreaks when they happen to preventing another situation like Covid-19 from escalating.

How do we prevent disease escalation? 

Three key messages jumped out to me from reading the latest immunisation coverage rates.

None of these are new challenges – but they require an urgent shift from responding to pandemics when they arise to preventing another situation like Covid-19 from escalating.

1. We need global collective action on infectious disease 

This is the biggest continued backslide in vaccinations in 30 years and it’s disproportionately affecting the most vulnerable.

Just ten countries account for the six in ten children who miss out on access to all life-saving vaccines. Roughly the same countries also account for six in ten of the children missing out on a measles vaccine.

With outbreaks already being reported in Africa and the Eastern Mediterranean, the huge numbers of children missing out on vaccination is a real and immediate threat that can create dangerous conditions for deadly diseases to escalate. For vaccines to work, coverage must be high.

2. We need to act early, predict and prevent  

Measles is often described as ‘the canary in the coal-mine’.

It’s the first outbreak we see when immunisation rates are low and an indication of dangerous things to come. Measles outbreaks come first because it’s so infectious and measles vaccines need very high coverage to be effective.

While action was taken when Covid-19 infections rose above an R-rate of 1, measles has a staggering R rate of 12-18. That means an average of 15 people are infected from just one case.

With a drop in coverage and outbreaks spreading once again, measles is offering a warning sign that we need to take action. But waiting for outbreaks to begin isn’t the best way to protect the most lives and keep infectious disease under control.

For prediction and prevention to work best, we need strong, robust global surveillance systems with the capacity to measure and map the sources and drivers for all infectious diseases, using the best technologies from genomic surveillance to citizen-generated data.

3. Access is key to preventing escalation 

The path from research to licensure is not enough.

Vaccines only work when they are given to the people who need them. But, as the data shows, while it’s brilliant that the number of new vaccines being introduced in different countries is increasing, coverage levels for existing vaccines are struggling to keep up.

More needs to be done to make sure vaccines are easy to access and that people know how, when and why to get them.

This is not just essential for immunisations to address current infectious diseases but also for ensuring we have resilient infrastructure for the introduction of future vaccines like TB, Dengue and Respiratory Syncytial Virus (RSV).

Part of the solution is a set of practical interventions to make it simple for people to book and keep appointments. But there are also still research gaps that need filling to give us more robust evidence around what’s causing low coverage and the solutions for better predicting and preventing future escalation of infectious diseases. The gaps are often context specific.

This means working closely with those in the areas disproportionately affected and most vulnerable to future threats and bringing together expertise from a range of disciplines, keeping equitable access at the heart of everything we do.

What needs to happen now? 

Fortunately, Immunisation Agenda 2030 (IA2030) offers a clear strategy and a committed global partnership whose mission is to tackle this crisis. Wellcome’s focus on escalating infectious disease means we shall continue to play our part too.

But, for us to succeed we need all governments, funders, civil society and wider immunisation partners to take the following collective action:

  • Leverage and increase investment in research to develop and improve new and existing vaccines and immunisation services that can achieve community needs and deliver on IA2030 goals. 
  • Prioritise health information and disease surveillance systems strengthening to provide the data and monitoring needed for programmes to have maximum impact.  
  • Ensure current pandemic preparedness and response and the global health architecture strengthening efforts lead to investment in primary health care (PHC) services, with explicit support to strengthen and sustain essential immunisation. 
  • Ensure political commitment from national governments and increase domestic resource allocation to strengthen and sustain immunization within PHC. 
  • Implement evidence-based, people-centred, and tailored strategies to build trust in vaccines and immunisation, counter misinformation and increase vaccine uptake particularly among vulnerable communities. 
  • Intensify efforts for catch-up vaccination to address backsliding on routine immunisation, and expand outreach services in underserved areas to reach missed children and implement campaigns to prevent outbreaks. 

The time to act is now. 

We’re funding research to better understand what causes and drives infectious diseases to escalate and the solutions to control their impact. Explore our current funding call(s):

Strengthening health and disease modelling for public health decision making in Africa