Terrorist Attacks Against Vaccinators: A Review

Introduction

Vaccination has been a core public health strategy to prevent a wide range of infectious diseases for over 2 centuries. Mass vaccination has led to the eradication of smallpox and the elimination of polio in most parts of the world.^1,2 During outbreaks and pandemics, including the 2009 H1N1 influenza pandemic, vaccines have proven instrumental in curbing disease transmission and limiting their adverse impact on society.^3,4,5 It has been said that apart from clean water, vaccination has saved more lives than any other medical intervention. ⁶

Mass vaccination is operationally complex. ⁷ Vaccinators must be healthcare personnel trained to safely administer the vaccine and monitor for side effects. Recipients must be physically present to receive their dose, which introduces significant throughput and security challenges at large public events. Temperature-controlled supply chains are often required to preserve the effectiveness of the vaccine as it is distributed. ⁸ Additional support personnel are also necessary to ensure complete documentation and coordinate future vaccinations when more than 1 dose is needed to achieve durable immunity. In lower-income countries and conflict zones lacking a functional public health infrastructure, humanitarian aid workers play a crucial part in delivering vaccines to vulnerable populations, often in remote areas. ⁹ The logistical challenges associated with mass vaccination campaigns can render them highly visible and therefore vulnerable to attacks from those wishing to inflict harm on healthcare professionals and the communities they serve.

Unfortunately, vaccinators in many countries have become victims of targeted violence. The most striking example occurred in late 2012 when 9 polio vaccinators were killed by Taliban militants in Pakistan. ¹⁰ Attacks against vaccinators can have long-term, detrimental effects on a nation's efforts to promote public health. Understanding how and why vaccinators have been targeted in the past is an important first step to ensuring their future safety. This retrospective analysis describes terrorist attacks against vaccinators documented in the Global Terrorism Database (GTD).

Methods

The GTD is an open-source database maintained by the National Consortium for the Study of Terrorism and Responses to Terrorism (START), based in College Park, Maryland, that reports information on terrorist attacks occurring from 1970 to 2018. ¹¹ To be included in the GTD, an incident must be intentional, entail some level of violence or immediate threat of violence, and be perpetrated by subnational actors. Furthermore, an incident must meet at least 2 of the following 3 criteria: (1) the act must be aimed at attaining a political, economic, religious, or social goal; (2) there must be evidence of an intention to coerce, intimidate, or convey some other message to a larger audience than the immediate victims; and (3) the action must be outside the context of legitimate warfare activities. ¹¹

A search of the GTD was performed utilizing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard to identify terrorist attacks targeting vaccinators and vaccination campaigns. ¹² A total of 191,465 entries involving intentional global incidents spanning 48 years have been reported in the GTD. Using the search terms “hospital,” “healthcare,” “clinic,” “doctor,” “nurses,” “vaccinators,” and “vaccinations,” a smaller dataset of healthcare-specific incidents was created comprising 2,322 entries. This dataset was further refined to vaccination-related incidents applying the search terms “vaccinators,” “vaccinations,” and “vaccine,” resulting in a final set of 133 entries. To ensure that these entries accurately represented attacks against vaccinators, manual review of each entry confirmed appropriateness for inclusion.

This study was deemed to be exempt from review by the Washington University School of Medicine Human Research Protection Office.

Results

We identified a total of 133 articles in the GTD mentioning terrorist attacks involving vaccinators and staff supporting vaccination efforts. The first instance of a targeted attack occurred in 1980 in Rhodesia (now Zimbabwe). After 1980, there was not another attack on a vaccinator until 2000. Four attacks took place between 2000 and 2010. After 2010, every year had multiple attacks against vaccinators. The majority of attacks occurred between 2012 and 2015; the highest frequency of attacks per year was 42 attacks in 2014, followed by 33 attacks in 2013, and 16 attacks each in 2012 and 2015. Table 1 shows the full breakdown of attacks by year.

The majority of attacks occurred in the Middle East, South Asia, and sub-Saharan Africa. Attacks on vaccinators affected a total of 12 countries: Afghanistan, Angola, Central African Republic, Greece, Nigeria, Pakistan, Philippines, Rhodesia/Zimbabwe, Somalia, Sudan, Syria, and Yemen. The overwhelming majority of attacks, totaling 107, occurred in Pakistan, followed by 12 in Afghanistan and 5 in Nigeria. The other countries experienced 1 attack each.

“Unknown” groups carried out the majority of attacks against vaccinators, with a total of 85 incidents. In these instances, either no group publicly claimed credit for the attacks or the GTD staff were unable to ascertain the group from their research. Of the terrorist groups identified, the most attacks were perpetrated by Tehrik-i-Taliban Pakistan (22), Boko Haram (5), Lashkar-e-Islam (5), Taliban (Afghanistan) (4), and Jundallah (Pakistan) (3). Table 2 lists all terrorist organizations responsible for targeting vaccinators.

A review of the modes of attack against vaccinators revealed that 75 attacks involved an armed assault, 35 attacks involved the use of explosives and bombings, 17 attacks involved hostage-taking, 5 attacks were on facilities/infrastructure, 3 attacks involved an unarmed assault, and 1 attack involved an unknown modality. Weapons used to target vaccinators included firearms in 83 attacks, explosives in 33 attacks, melee weapons in 5 attacks, incendiary devices in 2 attacks, sabotage equipment in 1 attack, and “other” in 1 attack; it is not known what weapons were used in the remaining 9 attacks.

A total of 135 vaccinators and security officers supporting vaccine efforts were killed and 130 more wounded during these attacks; 116 attacks (87%) were documented as specifically targeting polio vaccination efforts.

Discussion

Vaccinators are crucial to improving the overall health of their countries. In many lower- and middle-income countries, these healthcare personnel continue the mission of vaccinating people against diseases that have already been eradicated in higher-income countries. Mass vaccination against a communicable infectious disease can drastically improve the public health of a country. ¹³ Unfortunately, vaccinators have also been the victims of deliberate terrorist attacks.

As documented in the GTD, more than 200 vaccinators and staff supporting vaccination efforts were wounded or killed in terrorist attacks between 1970 and 2018. These attacks, however, appear to be a relatively recent phenomenon. Aside from an instance in 1980, all attacks identified in this study occurred after 2000 and with increasing frequency. A troubling trend has emerged in the past decade, with every year since 2011 recording multiple attacks. The most targeted violence against vaccinators occurred in 2014, with 42 events recorded. The increasing frequency of attacks against vaccinators and vaccination sites is concerning and raises the possibility that terrorist organizations are becomingly increasingly comfortable and confident in coordinating and executing attacks against vaccinators.

In addition to being a new phenomenon, terrorist attacks against vaccinators appear to be confined to certain regions of the world. Aside from 1 attack in Europe, 133 attacks against vaccinators recorded in the GTD occurred in the Middle East, South Asia, or sub-Saharan Africa. Pakistan has experienced 80% (n = 107) of the recorded attacks against vaccinators, the most of any country. The high rate of violence against vaccination workers in Pakistan is perhaps not surprising given the degree of political instability in certain regions and the local Taliban's ban on receiving polio vaccines. ¹⁴

Interestingly, nearly all of the terrorist organizations identified in the GTD as having conducted attacks against vaccinators are religious extremist organizations. Tehrik-i-Taliban, also known as the Pakistan Taliban, has carried out the most attacks against vaccinators, claiming 22 attacks. Boko Haram, Al-Shabaab, Lashkar-e-Islam, Jundallah (Pakistan), and the Taliban (Afghanistan) have also attacked vaccine workers. Only 3 terrorist organizations listed—the Baloch Liberation Front, the Front for the Liberation of the Enclave of Cabinda, and the Sudan's People's Liberation Army—are not religious extremist organizations. However, the fact that most attacks documented in the GTD were perpetrated by unknown terrorist organizations limits the conclusions that can be drawn from this pattern.

Our findings highlight a need to protect vaccinators and the staff that support them, especially when operating in certain regions of the world. The dangers facing humanitarian and aid workers in conflict zones has been well documented.^15-17 Vaccinators in higher-income countries operate in similar environments but there are important differences in how they have been attacked. A 20-year review by Morokuma et al ¹⁸ found that the most common method of attack against aid workers was bombing followed by gun attacks. In our study, however, terrorists who attacked vaccinators were more likely to use firearms than bombs. This is noteworthy because firearms increase the exposure of the attacker due to their need to be physically close to the victim, whereas bombs limit exposure and are therefore usually preferred by terrorist organizations. The fact that terrorists overwhelmingly chose firearms to attack vaccinators suggests they were not concerned about exposure. Another indication that vaccinators were inadequately protected during their work is that 17 instances involved vaccinators being taken hostage. This suggests that terrorist organizations were able to defeat any security presence and capture vaccinators. The use of firearms lends further credence to the idea that vaccination sites are intrinsically more vulnerable than other targets.

Terrorist organizations have used brazen and brutal methods of attack when targeting vaccination efforts. These attacks appear to be confined to certain parts of the world, but their increasing frequency is concerning as it may indicate a rise in violence against this group of healthcare workers. Thus, government and security officials should take proactive steps now to protect vaccination workers and stem this violence to prevent its further expansion.

The question of how best to protect vaccinators is crucial to ensuring the success of future mass vaccination initiatives. In addition to increasing physical protection for vaccinators, governments and public health organizations need to engage their populations to emphasize the health benefits of vaccination. These same organizations should work to ensure the vaccination process remains apolitical and counter misinformation that may incite anger or fear. Ultimately, these strategies need to be tailored to meet the specific needs of the local population.^19,20

Increasing physical security around vaccinators, however, may have unintended, detrimental effects on their work. For a mass vaccination drive to be successful, it must be highly visible, welcoming, and easily accessible to the public.^21,22 Increasing security around the workers and the physical location may discourage members of the community from participating. ²³ The addition of security measures such as physical barriers or armed personnel must be carefully balanced against the need to welcome members of the public into the vaccination clinic.

One important question our findings raise is the motivation for these attacks, which is not captured in data compiled in the GTD. While the motives are likely as diverse as the terrorist organizations themselves, understanding the basis for these attacks is also important. Reasons for this violence may vary by geographic location but often center on distrust of the vaccine's benefit and the vaccinator's intentions. ²⁴ In addition to increasing protection for the workers, governments and other health and security organizations must counter false narratives regarding vaccines.^25,26 Further research exploring the underpinning rationale for these terrorist attacks is needed but will be challenging to conduct.

This analysis was a retrospective, University of Maryland-sponsored, government-funded database search of unclassified terrorist attacks. The sources of data include government and private partnerships as well as media. There is a limited means to confirm or verify these data and to determine the extent of underreporting. Additionally, the database itself does not include foiled or failed plots, attacks in which violence is threatened as a means of coercion, incidents reported from low-quality sources, or attacks in conflict zones where the combatant may be “national” and fall outside of the inclusion criteria of the GTD. Due to limited high-quality sources in certain geographic areas, documentation of attacks in those areas may be conservative. There is also a gap in data collection from 1993 as the handwritten report cards were lost, although some data were later recovered. ¹¹ Because terrorism is a public safety and national security issue, there is a theoretical concern that the true nature, mechanism, and extent of some attacks could have been altered to avoid providing terrorists the means to incorporate evidence-based data into their attack planning. All of these factors may mean that the true incidence of terrorist attacks targeting vaccinators is underreported or misreported. Due to the retrospective design, no statements of causality can be made. Finally, it is not possible to abstract information about the motives of the terrorist organizations from the existing database. The inability to fully understand why vaccinators were targeted is certainly detrimental to preparation efforts.

Conclusion

Vaccinators play a crucial role in promoting the health of their communities and their countries. Unfortunately, in certain parts of the world, terrorists have used violence to disrupt their work. Protecting vaccinators and the staff that support their lifesaving work should be a top priority for all nations.