Solveig A. Cunningham and Hadewijch Vandenheede
There are over 230 million international migrants worldwide, and this number continues to grow. Migrants tend to have limited access to and knowledge about resources and preventative care in their communities of reception, but nonetheless they are often in better health by many measures compared with native-born people in their communities of reception and with the people they left behind at their place of origin. With time since arrival, however, immigrants’ health advantages often dissipate and they experience increases in health problems, especially obesity and diabetes, which are chronic diseases that are increasingly prevalent in the overall population as well and are associated with multiple co-morbidities and limitations. It may be that immigrants have specific health endowments leading to these health patterns, or that the processes involved in migration, including exposure to new environments, behavioral change, and stress of migration may also affect risks of obesity and other chronic conditions. Understanding the health patterns of migrants can be useful in identifying their specific health needs, as well as contributing to our understanding of how specific environments, changes in environments, and individual health endowments interplay to shape the long-term health of populations.
Emily Q. Ahonen
Occupational health and safety concerns classically encompass conditions and hazards in workplaces which, with sufficient exposure, can lead to injury, distress, illness, or death. The ways in which work is organized and the arrangements under which people are employed have also been linked to worker health. Migrants are people who cross borders away from their usual place of residence, and about one in seven people worldwide is a migrant. Terms like “immigrant” and “emigrant” refer to the direction of that movement relative to the stance of the speaker. Any person who might be classified as a migrant and who works or seeks to work is an immigrant worker and may face challenges to safety, health, and well-being related to the work he or she does. The economic, legal, and social circumstances of migrant workers can place them into employment and working conditions that endanger their safety, health, or well-being. While action in support of migrant worker health must be based on systematic understanding of these individuals’ needs, full understanding the possible dangers to migrant worker health is limited by conceptual and practical challenges to public health surveillance and research about migrant workers. Furthermore, intervention in support of migrant worker health must balance tensions between high-risk and population-based approaches and need to address the broader, structural circumstances that pattern the health-related experiences of migrant workers. Considering the relationships between work and health that include but go beyond workplace hazards and occupational injury, and engaging with the ways in which structural influences act on health through work, are complex endeavors. Without more critically engaging with these issues, however, there is a risk of undermining the effectiveness of efforts to improve the lot of migrant workers by “othering” the workers or by failing to focus on what is causing the occupational safety and health concern in the first place—the characteristics of the work people do. Action in support of migrant workers should therefore aim to ameliorate structural factors that place migrants into disadvantageous conditions while working to improve conditions for all workers.
Peter McIntyre and Tony Walls
From the first vaccine (cowpox, developed by Edward Jenner in 1796), more than 100 years elapsed before additional vaccines for broad population use (diphtheria toxoid, tetanus toxoid, and whole cell pertussis) became available between 1920 and 1940. Then followed inactivated polio vaccine in the 1950s, and live attenuated vaccines for measles, mumps, rubella, and polio in the 1960s. In 1979, global elimination of smallpox was formally certified, with the last human case occurring in Somalia, almost 200 years after Jenner administered cowpox vaccine to James Phipps.
In 2019, global elimination is tantalizingly close for maternal and neonatal tetanus and polio. Despite recent outbreaks, elimination has also been achieved at country and regional levels for measles and rubella and, if achieved globally, will offer, as it has for smallpox, large reductions in child mortality and morbidity and in health system costs. Short of elimination, it is important to define the public health impact of vaccines broadly and at the population level. These broader impacts include benefits to families flowing from prevention of long-term sequelae of infection in children, and to populations and health systems from reduced transmission of infection. Importantly, well-delivered vaccination programs will have a substantial impact by improving equality in health outcomes across populations. Broader impacts include reductions in syndromic disease beyond laboratory-proven infection (e.g., diarrhea and pneumonia), indirect reductions in disease in those not immunized (within and beyond age cohorts targeted by vaccine programs), and improvements in other health services driven by the infrastructure for vaccine delivery. Measurement of these broader impacts can be challenging and must also acknowledge the potential for trade-offs, such as replacement disease due to non-vaccine strains, as documented for pneumococcal infection.
The realization of the benefits of vaccines globally for all children began with the Expanded Program on Immunization (EPI) initiated by the World Health Organization (WHO) in 1974. The EPI focused on improving coverage of six already available but grossly underutilized vaccines—diphtheria–tetanus–pertussis (DTP), polio, measles, and Bacille Calmette–Guerin (BCG). Through the EPI, estimated global coverage for 3 doses of DTP increased from around 20% to over 85%. Subsequent to the EPI, the Global Alliance for Vaccines and Immunization (GAVI), the Global Immunization Vision and Strategy (GIVS), and, most recently, the Global Vaccine Action Plan (GVAP) have aimed to improve access to additional vaccines in the poorest countries. These include Haemophilus influenzae type b (Hib), hepatitis B, pneumococcal conjugate, rotavirus, and human papillomavirus (HPV) vaccines, all introduced in high-income countries from the 1990s. In this chapter, the scope and methodological issues in measuring public health impact are reviewed, and estimates of the global public health impact of individual vaccines in children summarized, concluding with potential future benefits to global child health from expanded maternal vaccination and vaccines under development.