As the COVID-19 pandemic enters its third year and the Omicron variant looms, the consequences of inequitable global vaccine distribution and delivery weigh heavily. “It’s a disturbing reflection on the state of the world when the availability of potentially life-saving vaccines is divided between those that have a lot of it and those that don’t even have a drop,” says Muhammad Pate, a Harvard University public health expert, and former Global Director for Health, Nutrition, and Population at the World Bank.
In many lower- and middle-income countries, vaccine stocks are low, placing the jab out of reach for many eager to get it. In higher-income nations with ample vaccine supplies, vaccine hesitancy has set in. Cheryl Cohen, an epidemiologist at the University of the Witwatersrand in South Africa, notes that South Africa now has ready access to COVID-19 shots, but as of late November, only 34% adults were fully vaccinated. “The challenge now is much more hesitancy than availability,” she says.
While there are many explanations for these situations, one is often overlooked: the concept of value. Whether for COVID-19 vaccines, or influenza, measles, and other illnesses, the global public health community has not agreed on a standard by which to value the total economic and social benefit of vaccines. Mark Jit, an epidemiologist at the London School of Hygiene and Tropical Medicine, says that with COVID-19, “It's very clear that the benefits of a vaccine are not purely health. They allow countries to relax some of these measures that have a big impact on the economy, but also on people's ability to live normal lives.”
Jit and other researchers worldwide are working to develop metrics that take into account the broader socioeconomic, regional and global benefits of vaccination. Given that most policy decisions involve some form of cost-benefit analysis, revaluing vaccines could raise their priority in the global public health agenda, and thus boost their development, distribution and uptake worldwide.
Not just a matter of life and death
The impact of infectious diseases are most commonly measured by deaths and hospitalizations, and the perceived success of a vaccine is largely dependent on how it reduces those numbers. But deaths and hospitalizations alone do not capture the full burden of an infectious disease. Non-lethal infections carry costly consequences as well. In South Africa, Cohen notes, roughly 20% of the population develops symptomatic flu every season. “With all of those mild infections, there is absenteeism from work and school, and there are people who are unemployed, but taken away from whatever activity they might be doing to contribute to the family well-being,” she says.
By overlooking the combined consequences of milder cases, standard measures can understate the real impact of a disease—and the value of a vaccine to mitigate it. That, in turn, can influence decisions about which vaccines to invest in, and how and where to deploy them.
Quantifying the broader impacts of vaccination can be challenging, but Maddalena Ferranna at Harvard School of Public Health sees clear indicators of benefit. “Typically, vaccinated children have better educational attainment; they attend school more frequently, and they perform better on tests,” she says. Caring for sick children, she adds, also puts a burden on families, including missed work and the potential for parents to get sick themselves.
Beyond individual households, vaccinated adults can remain active in the workforce, and contribute to broader herd immunity for those who have not received shots. COVID-19 has demonstrated the economic and social impact of a pandemic and the countermeasures meant to combat it. It has caused business closures and unemployment, economic stagnation in certain nations, decreases in collective mental health, and global supply chain disruption—little of which is quantified accurately with standard measures.
With better metrics, better decisions
Several research groups are now looking into alternative metrics that capture the full value of vaccines. Ferranna and her collaborator David Bloom, for example, are employing a methodology called social welfare analysis. “The first step is to determine the impact of vaccination on individual well-being,” says Ferranna; the researchers then pool individual results to produce “an aggregate measure of how vaccination improves the overall well-being of a society.”
This entails assigning monetary value to quantitative and qualitative indicators relating to health, education, work productivity, and overall quality of life. Such an approach could help policymakers and funders to draw direct comparisons between a given vaccine and other public health measures or interventions as well as define clearer value proposition for new vaccine research.
While the notion of a broader impacts assessment is decades old, Ferranna notes that “this type of approach hasn't yet taken off from a policy-making perspective.” Until that happens, policy decisions are likely to underestimate the potential benefits of vaccines. To that end, the WHO has recently proposed a framework for such assessments designed to focus on the agenda of all stakeholders, including low- and middle-income countries, rather than emphasize the return on investment for donors, as has been done in the past. “It’s proposing a way of looking at vaccines which isn’t purely reducing everything to a number, but instead takes a multifaceted look at the different benefits of the vaccine and how we assign value to that,” Jit says.
Lacking an understanding of the full value of vaccines can lead to missed opportunities to optimally invest in health and economic development. Pate points to funding delays that impeded the COVID-19 Vaccines Global Access (COVAX) facility, a public-private partnership whose mission is to support worldwide vaccine manufacturing and distribution. Wealthier nations delayed for more than eight months before investing the initial $6 billion needed to begin to secure and deliver vaccines to low- and middle-income countries.
The rapid spread of the Omicron variant, like Delta before it, shows that until the benefits of vaccines are extended to all, no individual nation will fully benefit from vaccination. In the face of this global threat and future ones, Pate says he hopes that funders will recognize vaccines’ profound socioeconomic impact and invest accordingly. “When you’re financing a global public good, it’s for everyone—not necessarily tied to each country,” he says.