Valuing vaccination

Many health interventions, including vaccinations, have been subjected to economic evaluation. Historically, economists have taken a narrow approach to valuing vaccination’s benefits by focusing strictly on a subset of the potential benefits, mainly averted health care spending. Some existing studies also capture those productivity gains that arise because vaccination protects people from losing productive time due to their own health care utilization or the need to provide or seek care for their children or other household members. These narrow sources of economic benefit associated with vaccination are closely linked to health care and, for most routinely recommended vaccinations, are large relative to the cost of vaccination (16). Nonetheless, failing to account for the full spectrum of benefits—including some important instrumental effects of vaccination on economic well-being—will result in an undervaluation of vaccination. The failure to measure the full benefits of vaccination could be especially important when evaluating the new generation of more expensive vaccines, at least some of which will require heavy ancillary investment in nonvaccine costs such as cold chain storage space and human resource capacity (17). To address this undervaluation bias, we argue for expanding the conceptualization of vaccination benefits, moving from a narrow to a broad (i.e., full benefits) approach (Table 1).

This broad approach considers the benefits that come from avoiding the long-term mental, physical, or cognitive impairments that many vaccine-preventable diseases can cause (22–26), for example, blindness resulting from measles infection (27, 28), hearing loss from mumps (29), or cognitive diminution from intrauterine rubella (30). Naturally, these health problems (and avoiding them via vaccination) can impact educational attainment, adult earnings, and social functioning (31–35). Thus, outcome-related productivity gains are benefits that follow on from improved health due to vaccination. The broad approach also considers behavior-related productivity gains, which result because reducing the burden of vaccine-preventable disease can lead to behavior change affecting productivity (36). For example, if a couple believes their children’s chances of survival have increased as a result of their being vaccinated against disease, the couple may decide to have fewer children and to invest more resources in each child (e.g., spending on health care and education) (37). These behaviors are presumed to improve household well-being and may spur economic growth through realization of a demographic dividend (15, 38).

Commonly, not only the people who receive a vaccination but also the unvaccinated derive benefits from widespread vaccination. Community health externalities include herd effects, whereby unvaccinated members of a community incur protection from disease through the vaccination of others (39–47). They also include reduced use of antibiotics to fight vaccine-preventable diseases and, as a consequence, slower development of antibiotic resistance (48, 49). Community economic externalities occur because high rates of vaccination and reduced disease transmission can make a country more desirable for domestic investment and FDI, as well as for tourism and immigration (14). Finally, vaccination reduces risk, and risk reduction implies lower need for ensuring against the future possibility of incurring a disease, as well as welfare gains due to reduced anxiety and worry. Along with the utilitarian value of health gains (i.e., those above and beyond their instrumental value for economic well-being), all these vaccination effects are valuable to individuals and the societies in which they live; ignoring these effects in economic evaluation studies will lead to systematic underestimation of the value of vaccination.

Despite the potential importance of the broad benefits of vaccination at the individual and population levels, recent reviews of the literature reveal that many of these benefits are typically neglected in economic evaluations of vaccination (18, 50, 51). The existing reviews on this topic contribute two major findings: First, only a small portion of existing economic evaluation studies takes a broad view of the benefits of vaccination, and even those that do are relatively confined in how far they go beyond the narrow benefit categories. For instance, Bärnighausen et al.’s review of the types of benefits that have been captured in existing benefit-cost analyses of Hib vaccination finds only one study each that accounts for outcome-related productivity gains and community externalities (18, 50, 51), whereas none of the other studies account for any benefits beyond the traditionally captured health care cost savings or care-related productivity gains. In another systematic review, Deogaonkar et al. searched the literature for economic evaluation studies of vaccinations in low- and middle-income settings that take a broader perspective and find that, of the 26 articles published between 1990 and 2011, 8 capture community health externalities and a separate 8 studies capture outcome-related productivity gains. No study takes into account behavior-related productivity gains or community economic externalities (50). In a third systematic review, Ozawa et al. examined economic evaluations of vaccinations in low- and middle-income countries (51) and conclude that “[t]here were little data on long-term and societal economic benefits such as morbidity-related productivity gains, averting catastrophic health expenditures, growth in gross domestic product (GDP), and economic implications of demographic changes resulting from vaccination” (51).

Second, the existing reviews demonstrate that new research is needed to produce more robust evidence on the full benefits of vaccination. A number of scholars around the world have started to conduct such studies (19, 31, 33, 50–55).

Table 2 provides an overview of the emerging research on the full benefits of vaccination. Some studies focus on individual vaccinations, whereas others focus on clusters or packages of vaccinations. Some focus on existing vaccinations, whereas others seek to understand the benefits of prospective vaccination (20, 55). Different studies also focus on various subsets of the full benefits framework. Notably, no study to date captures all sources of benefit from vaccination. However, the ones that do focus on measuring full benefits generally find them to be substantial in magnitude (18, 31, 33, 55). For example, many existing studies of the Hib vaccination show the vaccination costs to be below or to barely outweigh the benefits (20, 56). However, Bärnighausen et al. show that incorporating broad benefits of Hib vaccination would drive its benefit-cost ratios well above 1 in a range of studies, indicating that the vaccination should be included in national immunization programs because it is net beneficial to society to do so (18). A study by Canning et al. that analyzed antenatal tetanus vaccination in mothers of low socioeconomic status in Matlab, Bangladesh, demonstrates that, in addition to improving child survival and preventing cognitive impairment in children of vaccinated mothers, vaccination can also promote educational attainment and subsequent wage gains (on the order of 2.5%) in those children (31). The authors find that the benefits and costs of maternal tetanus vaccination compare favorably to other potential investments to improve educational attainment for children from low-income households. Similarly, a study that calculated the return on investment in a GAVI Alliance program to extend coverage of new and underused childhood vaccination in 75 low-income countries during 2005–2020 estimates that the rate of return would be 12% in the first year of the program and rise to 18% in year 15 (55). These estimated rates of return compare favorably with average rates of return to schooling, which is a well-known and potent driver of economic well-being. Notwithstanding these strong results, the authors argue that the figures are conservative because they did not account for additional benefits such as reduced pain and suffering among survivors or demographic dividend effects and that a full benefits approach would lead to even more favorable estimates of return on investment.

Implementing an economic evaluation of a vaccination intervention that adopts a full-benefits approach requires attention to five key items.

The emergence of new ideas, theoretical models, and empirical evidence on the economic benefits of health has added health interventions to the arsenal of major instruments for promoting economic well-being. For some health interventions, outcome-related productivity gains, community health externalities, community economic externalities, and the value of pure health gains have been explored (51, 60–63) but studies like these are more the exception than the rule. By contrast, economic evaluations of education typically adopt a broad approach, commonly focusing on outcome-related productivity gains—education’s impact on work participation, productivity, and earnings throughout the life course (64). Some studies have also highlighted other broad benefits, including spillovers of education on political stability, poverty reduction, and crime (65, 66), although the literature has yet to capture the full benefits of education in a single pecuniary measure.

By routinely failing to account for the full spectrum of benefits of health interventions, economists have unwittingly undervalued many health interventions (18, 20, 21). The ensuing biases are likely to be especially large in the case of vaccination. First, vaccinations are commonly given in early life phases, and the returns on vaccination investments, such as improved school attainment, economic productivity, and social functioning, are reaped throughout the life course (31–33). Second, vaccinations often disrupt transmission chains of infectious diseases throughout the community, leading to multiplier effects for the broader economic and social benefits of vaccination (20, 39–44, 67). Third, the child survival benefits of vaccinations typically catalyze or accelerate fertility decline and create potentially sizable opportunities for economic growth.

Overall, the studies reviewed herein suggest that important and large vaccination benefits have been routinely ignored in economic evaluation studies. Although the resulting undervaluation bias may not have had important practical implications for well-established and low-cost vaccinations, such as those in the World Health Organization (WHO)’s Expanded Program on Immunization, it will likely guide policy makers toward underinvestment in expanding coverage with a new generation of more costly vaccinations, such as those against rotavirus, pneumococcal disease, and HPV—to the peril of the populations whose health and welfare these vaccinations could improve. A harder to estimate but potentially even more detrimental effect of systematic vaccination undervaluation is underinvestment in discovery and development of new vaccines (68). Potential market size is an important motivator for private industry to develop new products (69–71); adoption of vaccinations into national immunization plans will thus be a powerful signal to industry that could influence research investment decisions (68).

Three general recommendations flow from our arguments and related synthesis of existing evidence on broad benefits of vaccination. First, many economic evaluation studies of vaccinations should be redone to capture the full benefits generated by the vaccination in question. Second, the evidence to date on the full value of vaccination has been focused on measuring the total social benefits generated. It would also be useful to explore the distribution of vaccination’s benefits among different possible beneficiaries. Third, the primary empirical evidence on broad vaccination benefits will need to be considerably expanded and improved (72). Although many studies have shown that these types of benefits can be substantial, for many benefit categories, the evidence base has not been firmly established. For instance, it seems highly plausible that dengue vaccination could increase tourism flows in dengue-endemic countries, such as Brazil and Malaysia. Dengue outbreaks are typically highly visible in the international media, and tourists may decide to avoid travel to countries experiencing an outbreak (58, 59, 73, 74). Although a dengue vaccine is not yet available, promising candidates are under development (75). Studies are needed of the causal effect of dengue outbreaks on tourism streams and revenues to test the claim that dengue vaccination can generate positive community economic externalities by reducing the frequency and intensity of outbreaks.

One largely unexploited strategy holds particular promise for providing rigorous evidence on broad vaccination benefits. Modern vaccinations have routinely been investigated in RCTs, but these trials have mostly focused on safety, immunogenicity, and efficacy end points and have ignored the impacts of vaccination on educational, economic, and social outcomes. Follow-up studies in the trial populations to assess impacts on broad outcomes could produce a compelling body of new evidence, although this approach may be limited by the ethical obligation to deliver successful interventions to control groups once efficacy is established. The fact that in the case of many such trials long periods of time will have passed since the original exposure assignment might pose challenges for ensuring good follow-up of the trial populations. On the other hand, with respect to the goal of establishing broad vaccination benefits, a long time between exposure assignment and outcome assessment will likely be an advantage, because many of the broad benefits, such as school attainment and labor market outcomes, will only manifest themselves over longer periods of time. Collecting economic and social indicators as part of vaccination RCTs, or after the main trial has been completed, offers a promising and practical approach for guarding against the undervaluation bias that has plagued economic evaluation of vaccinations for decades (31, 72). Observational studies can also be informative, especially insofar as they adjust statistically for nonrandom vaccination status using, for example, propensity score analysis or instrumental variables, or focus on within-family differences in vaccination status and related outcomes (33, 55, 57).

Insofar as biomedical advances hold great promise with regard to the introduction of new and improved vaccines, building a body of objective evidence on the full benefits and costs of vaccination will be essential to assessing the desirability of pursuing these innovations.

The authors thank Elizabeth Mitgang and Alyssa Shiraishi Lubet for helpful research assistance and the referees and editor for helpful comments.