To achieve and sustain high vaccine coverage, countries and communities will need to make progress in multiple areas.
Explore this diagram to understand the factors that contribute to vaccine coverage.
Delivering vaccines to all who need them means:
- Building strong delivery systems
Health systems need the capacity to tailor delivery strategies to community needs and reach under-served populations. - Involving communities
Communities need to understand the value of vaccines and to see—and demand—them as an essential health service. - Sustaining coverage in spite of challenges and threats
Health systems must be resilient and adaptable to changing contexts.
Building strong delivery systems
To achieve high vaccine coverage, health systems need to account for barriers to immunization in each community, tailoring service delivery to meet local needs. At the same time, they need to devise strategies that can target under-served communities: remote rural populations, mobile populations, cultural minorities, and disadvantaged people and groups.
Vaccine delivery strategies often include providing services within communities: at schools and markets (e.g. shopping centers), for example. These can be regular vaccination clinics (known as “outreach vaccination”) or periodic “child health weeks” that deliver a full package of child health services. Vaccination campaigns that rapidly immunize many people at once also play an important role in preventing and controlling disease outbreaks. Efficiently reaching everyone with the right vaccines at the right time means balancing routine primary health care vaccine delivery programs and special strategies such as vaccination campaigns.
In many places, private-sector providers play an important role in health care. These providers, including non-governmental organizations and for-profit providers, should partner closely with the public health care system to support access to immunization, ensure quality of care, and monitor coverage.
Vaccination programs should not be static—they need to evolve with updated recommendations for the use of existing vaccines and as new vaccines become available. For instance, WHO has recommended additional doses of measles and DTP vaccines after infancy to expand and prolong protection. Human papillomavirus vaccine is now recommended for all adolescent girls to protect them against many types of cancers, and reaching and protecting school-age girls requires new strategies and partnership with education systems. Emerging and future vaccines—for malaria and human immunodeficiency virus (HIV), for example—will target different ages and risk groups and require tailored approaches for delivery. Delivery systems will need to adapt to these changes to realize the full benefits of immunization.
Engaging communities
When communities understand the value of vaccines, their members actively seek out immunization as an essential health service. Making this happen requires a public understanding of the value of vaccination that is built on sound and credible evidence related to the risks of disease, benefits of vaccination, and vaccine safety. Effective communication must be tailored to its audiences and address community attitudes; for example, education systems can play an important role in improving vaccine awareness and building social norms around immunization.
In addition to building trust and encouraging greater use of services, public awareness of the value of vaccines can help boost social and political commitments to strong, comprehensive health systems. Community advocacy and collective action can hold leaders accountable for quality of services, creating a virtuous cycle that improves delivery systems, vaccine coverage, and health outcomes.
Today, as trust in vaccines is being undermined by the spread of incorrect information about their safety and value, it is especially important to counter misinformation. (Misinformation has real consequences: in some communities, it has started to erode progress against preventable diseases such as measles.) Active community engagement is needed to address concerns and to build confidence and trust.
Sustaining progress
Immunization systems need to be resilient if they are to sustain coverage in the face of challenges and threats, including:
- Declines in development assistance
Development assistance has helped increase immunization coverage in most low- and lower middle-income countries. But as they grow wealthier, many of these countries will have less access to financial and technical assistance; as a result, they will need to rely more on domestic resources to sustain their immunization systems. - Population movement
Whether driven by conflict or climate change or by more benign processes such as urbanization, migration creates new populations which can be difficult to track and serve. Dense urban populations and displaced-persons settlements warrant special attention, since they can be particularly vulnerable to outbreaks of disease. - Conflict, violence and natural disasters
Armed conflict and natural disasters such as earthquakes and tsunamis damage civil infrastructure and health systems, making it more difficult to deliver essential health services. At the same time, they can increase the risk of infectious diseases by reducing access to clean water, sanitation, and hygiene and causing drops in vaccine coverage. - Disease outbreaks
Emerging infections such as Ebola and vaccine-preventable diseases such as diphtheria, measles, meningitis and yellow fever disrupt societies and health systems. Preparing to detect and respond to these outbreaks will limit their impact.