Immunization strategies: What lessons can we learn from successful campaigns?

By Deliana InfanteReviewed by Lily Ramsey, LLM

Introduction 
Understanding immunization campaigns
Key elements of successful immunization campaigns
Case studies of successful campaigns
Challenges overcome in these campaigns
Lessons learned for future immunization efforts
The role of innovation in immunization strategies
Conclusion 
References 
Further reading

Immunization strategies have been instrumental in controlling and eradicating diseases on a global scale. By analyzing successful campaigns, valuable lessons can be learned to strengthen future efforts. Implementing effective communication, engaging communities, and overcoming vaccine hesitancy are key components that provide invaluable insight for optimizing immunization programs and ensuring global health security.

Introduction

Vaccines have long been utilized to combat diseases, saving millions of lives worldwide. Immunization stimulates the body's defense systems to generate a protective response against over 20 pathogens that cause diseases, preventing approximately 5 million deaths each year from illnesses such as influenza and tetanus.¹

To ensure the success of a vaccination campaign, it is necessary to implement certain strategies. These include collaborating with and educating communities through health providers, combating misinformation by debunking myths that cause doubts about the use of vaccines, and providing accurate information about the benefits of vaccination.²

Understanding immunization campaigns

The primary objective of immunization campaigns is to eliminate or control diseases and reduce their transmission to vulnerable populations. Additionally, mass vaccination can achieve herd immunity, which helps prevent disease outbreaks.^2-3

These campaigns aim to provide access to vaccines for all populations, regardless of location or socioeconomic status, while also dispelling myths and common misconceptions about vaccines.^2-3

There are various vaccination strategies, which can be implemented at the national or regional level. These strategies are mainly classified as Supplementary Immunization Campaigns/Activities (SIAs), Periodic Intensification of Routine Immunization (PIRI), and Outbreak response campaigns.^4-5

SIAs aim to raise the immunity of the population against any pathogen or disease and reduce the number of susceptible individuals to control or eliminate the threat, regardless of their vaccination history.^4-5 PIRI are intermittent or time-limited and aim to administer routine vaccines to unvaccinated populations while educating them about the benefits. ^4-5

Outbreak response campaigns are deployed in crisis situations, such as epidemics, with the goal of quickly protecting vulnerable populations by providing essential vaccines. This emergency response vaccination can prevent the spread of diseases and save lives.⁵

Key elements of successful immunization campaigns

Successful immunization campaigns require careful planning, execution, and community engagement to ensure high vaccine uptake and coverage.

Robust delivery strategies, such as SIAs and PIRIs, should be employed to quickly reach large numbers of individuals, particularly under-vaccinated populations, and raise awareness of vaccination benefits.^4-5

Quality improvement programs, such as Immunization Quality Improvement for Providers (IQIP) and Immunization Information Systems (IISs), are essential for tracking and improving vaccination rates within healthcare practices.⁶ The use of digital technologies, such as electronic immunization records, or smartphone applications can greatly support vaccination programs.⁶

Healthcare practices should promote a culture of immunization, working towards community engagement, which is essential for increasing routine immunization rates.⁶ This involves assessing barriers to vaccination, profile public perceptions, and involve health workers with community leaders and members in monitoring vaccination programs.^6-7

Case studies of successful campaigns

One of the most notable disease eradication efforts targeted the smallpox virus, a highly contagious and often deadly disease that had tormented populations for centuries.⁸

In 1966, the World Health Organization (WHO) initiated a campaign to control and immunize populations against smallpox, focusing primarily on ring vaccination. This strategy involved vaccinating close contacts of infected individuals and establishing efficient surveillance systems. By 1980, the concerted efforts of international cooperation and an effective vaccination program led to the official declaration of smallpox eradication.⁸

Another prominent campaign has been against the poliovirus, which can cause disability and sometimes fatal illness. The WHO launched an eradication effort for polio in 1988. While the campaign has succeeded in reducing the disease by 99%, sporadic outbreaks still occur. The Global Polio Eradication Initiative (GPEI) coordinates widespread vaccination campaigns, administering multiple doses of the polio vaccine to millions of children, while also working on improving access to clean water and sanitation infrastructures.⁹

Recently, the COVID-19 pandemic has promoted extraordinary global efforts to develop and distribute vaccines rapidly and effectively, with nearly 12 billion doses administered worldwide.¹⁰

Although the battle against COVID-19 persists, continuous promotion of vaccination plays a critical role in reducing hospitalizations and fatalities. An unprecedented collaboration among governments, scientific institutions, and pharmaceutical companies has facilitated the development, assessment, and production of COVID-19 vaccines at an unparalleled pace.¹⁰

Challenges overcome in these campaigns

There have been several challenges that have hindered immunization initiatives. For instance, during the smallpox eradication campaign, the primary issues faced included accessing remote areas, maintaining the cold chain, addressing failures in safety and efficacy assessments, and training healthcare workers in vaccine administration.⁸

This vaccine had been available for over a century; however, its production was largely unregulated, leading to concerns regarding vaccine safety.⁸ Despite these concerns, it remains the best example of a successful immunization campaign. The dedication of local leaders, and healthcare providers played a pivotal role in dispelling myths and addressing concerns about vaccination.⁸

On the other hand, efforts to eradicate polio encountered serious challenges, particularly in accessing high-risk communities, especially in low-income countries and areas with limited healthcare infrastructure.⁹ These challenges made it difficult to reach every child with the multiple doses of vaccine required.⁹

The polio vaccine did not provoke widespread rejection by the public. However, a tragic manufacturing error led to a bad batch of vaccines that caused deaths and paralysis. This incident temporarily halted the vaccination program.¹¹

Lastly, the COVID-19 vaccination campaign faced its own challenges. The rapid development of vaccines under "Operation Warp Speed," coupled with the spread of misinformation, has led to vaccine hesitancy.¹² Additionally, securing high vaccine uptake and ensuring efficacy against new variants of the virus have posed further challenges.¹⁰

In general, a common setback across all these campaigns has been data collection, particularly in middle- and low-income countries. Robust protocols for data collection and transparent record-keeping are critical for assessing the safety and efficacy of immunization programs.

Image Credit: PeopleImages.com - Yuri A/Shutterstock.com

Lessons learned for future immunization efforts

The eradication of smallpox, the ongoing battle against polio, and the rapid response to COVID-19 have unequivocally illustrated the significance of global cooperation and the pivotal role of international systems in addressing public health challenges.

These efforts have been bolstered by innovative solutions to navigate through conflicts, vaccine hesitancy, and the advent of new pathogens, underscoring the necessity for continuous vaccine development and strategic deployment. Such endeavors not only aim to expand vaccine portfolios for various populations and diseases but also to prepare for imminent outbreaks and pandemics.^13-14

Achieving herd immunity through vaccines that block both disease and infection is critical, as it offers indirect protection to the vulnerable and those who cannot be vaccinated.^13-14 The backbone of these efforts is a robust public health infrastructure that ensures effective surveillance and laboratory networking.^13-14

Furthermore, fostering public trust through education is key in dispelling misinformation and achieving high vaccine uptake.^13-14 Long-term planning and predictability are also essential for the sustained success of immunization programs.^13-14

The role of innovation in immunization strategies

The fight against emerging infectious diseases demands cutting-edge immunization technologies. mRNA vaccines, for example, hold promise for defending against various strains or diseases simultaneously.¹⁵ Moreover, the invention of thermostable vaccines, which bypass the need for refrigeration, could be a game-changer for reaching isolated regions.¹⁶

Innovative methods of vaccine administration, such as painless microneedle patches, nasal sprays, and even ingestible vaccines, have the potential to enhance public compliance and simplify the logistics of mass vaccination programs.^17-18

Conclusion

Critical for any vaccination initiative is the synergy of collaborative efforts, global partnerships that span governments, private sectors, and local communities. As the dynamics of infectious threats and vaccine hesitancy shift, vaccination campaigns must remain flexible to tackle these changes proactively. This adaptability, coupled with a commitment to innovation, can surmount existing and future hurdles.

Furthermore, the backbone of any successful immunization strategy lies in a competent healthcare workforce, reliable distribution networks, and adequate storage capabilities. Investment in these critical areas solidifies the infrastructure necessary for enduring vaccine campaign effectiveness and sets the stage for enduring public health victories.

References

1. Vaccines and immunization. (2019). [Online]. Available at: https://www.who.int/health-topics/vaccines-and-immunization#tab=tab_1
2. Strategies effective in optimising COVID19 vaccine uptake. (n.d.). Australian Journal of General Practice. [Online]. Available at: https://www1.racgp.org.au/ajgp/2022/september/strategies-effective-in-optimising-covid19-vaccine
3. What CDC is Doing in Global Immunization. (2023). Centers for Disease Control and Prevention. [Online]. Available at: https://www.cdc.gov/globalhealth/immunization/framework/index.html
4. Immunization campaigns. (n.d.). WHO. [Online]. Available at: https://www.who.int/teams/immunization-vaccines-and-biologicals/essential-programme-on-immunization/implementation/immunization-campaigns#:~:text=Planning%20and%20Implementing%20High%2DQuality%20Supplementary%20Immunization%20Activities%20%28SIAs%29%20for%20Injectable%20Vaccines%20Periodic%20Intensification%20of%20Routine%20Immunization%20%28PIRI%29%2C%20is%20a%20term%20that%20describes%20a%20spectrum%20of%20time%2Dlimited%2C%20intermittent%20activities/campaigns%20used%20to%20administer%20routine%20vaccinations%20to%20under%2Dvaccinated%20populations%20and/or%20raise%20awareness
5. Immunization strategies. (n.d.). MSF Medical Guidelines. [Online]. Available at: https://medicalguidelines.msf.org/en/viewport/mme/english/2-3-immunization-strategies-32407842.html
6. Pinkbook | Immunization Strategies | Epidemiology of VPDs | CDC. (n.d.). [Online]. Available at: https://www.cdc.gov/vaccines/pubs/pinkbook/strat.html#:~:text=Standards%20for%20Child%2C%20Adolescent%2C%20and%20Adult%20Immunization%20Practices
7. Tripathi  S, et al. (2022). Designing appropriate, acceptable and feasible community-engagement approaches to improve routine immunisation outcomes in low- and middle-income countries: A synthesis of 3ie-supported formative evaluations. PLOS ONE, 17(10), e0275278. https://doi.org/10.1371/journal.pone.0275278
8. Smallpox was defeated, but it wasn’t easy. Here’s how it’s relevant to COVID-19. (n.d.). BrandeisNOW. [Online]. Available at: https://www.brandeis.edu/now/2020/may/smallpox-and-coronavirus-willrich.html#:~:text=The%20smallpox%20vaccine%20had%20been%20around%20for%20more%20than%20a%20century%20by%20this%20time%2C%20but%20vaccines%20were%20mostly%20produced%20by%20unregulated%20commercial%20enterprises
9. Lessons we can learn from polio vaccination campaigns. (2021). National Centre for Epidemiology and Population Health. [Online]. Available at: https://nceph.anu.edu.au/news-events/news/lessons-we-can-learn-polio-vaccination-campaigns
10. Aneja & Arora. (2024). Lessons from One of the World’s Most Successful, Yet Unusual, COVID-19 Vaccination Campaigns. O’Neill. [Online]. Available at: https://oneill.law.georgetown.edu/lessons-from-one-of-the-worlds-most-successful-yet-unusual-covid-19-vaccination-campaigns/
11. Schumaker, E. (2021). How COVID-19 vaccine rollout compares to smallpox, polio and others in the past. ABC News. [Online]. Available at: https://abcnews.go.com/Health/covid-19-vaccine-rollout-compares-smallpox-polio-past/story?id=75489514#:~:text=Polio%2C%20a%20contagious%20disease%20that%20can%20cause%20nerve%20damage%2C%20paralysis%20and%20death%2C%20and%20which%20mainly%20affects%20children%20younger%20than%205%2C%20terrified%20parents
12. Operation Warp Speed: Accelerated COVID-19 Vaccine Development Status and Efforts to Address Manufacturing Challenges. (2021). U.S. GAO. [Online]. Available at: https://www.gao.gov/products/gao-21-319
13. Vaccine Investment Strategy 2024. (n.d.). [Online]. Available at: https://www.gavi.org/our-alliance/strategy/vaccine-investment-strategy-2024#:~:text=The%20VIS%20operates%20on%20a%20five%2Dyear%20cycle%20to%20provide%20Gavi%20implementing%20countries%2C%20manufacturers%2C%20donors%20and%20other%20partners%20with%20predictability%20and%20information%20to%20support%20long%2Dterm%20strategic%20planning%20of%20immunisation%20programmes%2C%20as%20well%20as%20our%20upcoming%20strategic%20period
14. Bristol, N. (2023). Smallpox Eradication: A Model for Global Cooperation. [Online]. Available at: https://www.csis.org/analysis/smallpox-eradication-model-global-cooperation#:~:text=Smallpox%20eradication%20represented%20a%20common%20goal%20that%20served%20both%20countries%E2%80%99%20domestic%20interests%20in%20eliminating%20imported%20smallpox%20cases
15. Massaro, L. (2024). Vaccines to Watch in 2024. Drug Topics. [Online]. Available at: https://www.drugtopics.com/view/vaccines-to-watch-in-2024
16. Hosangadi D, et al. (2021). Supporting use of thermostable vaccines during public health emergencies: Considerations and recommendations for the future. Vaccine, 39(48), 6972–6974. https://doi.org/10.1016/j.vaccine.2021.10.065
17. Goodson & Rota (2022). Innovations in vaccine delivery: increasing access, coverage, and equity and lessons learnt from measles and rubella elimination. Drug Delivery and Translational Research, 12(5), 959–967. https://doi.org/10.1007/s13346-022-01130-9
18. Vaccine Administration Route and Site | CDC. (n.d.). [Online]. Available at: https://www.cdc.gov/vaccines/hcp/admin/administer-vaccines.html

Further reading 

• What are the Different Types of Vaccines?
• What are the Main Causes of Vaccine Hesitancy?
• An Overview of the COVID-19 Vaccines