The long view of vaccination to secure the future

Abstract

“Whether this distribution of benefits will be attractive to finance ministers depends on many factors”—so state Chloe Puett and colleagues in their analysis of the long-term economic benefits of Shigella vaccination to prevent linear growth faltering (LGF) in The Lancet Global Health.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar The cost of vaccination can be a considerable deterrent in the introduction of a new vaccine, and has contributed to the low coverage rates of rotavirus vaccines and the human papillomavirus (HPV) vaccine, which, where it has been introduced, is only focused on girls and young women,2Bruni L Saura-Lázaro A Montoliu A et al.HPV vaccination introduction worldwide and WHO and UNICEF estimates of national HPV immunization coverage 2010–2019.Prev Med. 2021; 144106399Crossref Scopus (173) Google Scholar despite having been shown to be beneficial in men.3Stanley M HPV vaccination in boys and men.Hum Vaccin Immunother. 2014; 10: 2109-2111Crossref PubMed Scopus (28) Google Scholar The strength of the analysis by Puett and colleagues is the novel approach it takes in describing benefit–cost ratios (BCRs), calculating the enhanced future productivity of children who have received a Shigella vaccine, through the reduction of LGF.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar Assuming a retirement age of 64 years, they calculated that the income effect of the BCR in low-income countries (LICs) and lower-middle-income countries (LMICs) would be 11·60, compared with a BCR of 8·53 when upper-middle-income countries were included.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar These analyses could be extended to other vaccines, including those in the process of being introduced (eg, the HPV and rotavirus vaccines) and others in the pipeline or in early development (eg, vaccines for respiratory syncytial virus, other enteric diseases, and tuberculosis). However, Puett and colleagues’ estimates are highly conservative, as they do not include other potential cost-benefits of Shigella vaccines. Shigella is highly transmissible and requires only a small infective dose; it is increasingly becoming multidrug-resistant and can either be endemic or cause significant outbreaks.4Kotloff KL Shigella infection in children and adults: a formidable foe.Lancet Glob Health. 2017; 5: e1166-e1167Summary Full Text Full Text PDF PubMed Scopus (12) Google Scholar One can therefore intuit that, besides the cost-benefit in future productivity, a more immediate and medium-term cost-benefit would be seen, because of decreased transmission and herd immunity, diminished use of antimicrobials (particularly of new, expensive compounds), and reduced health-care consultations and hospitalisations (obviating the need for a public health response due to Shigella outbreaks and limiting the indirect costs on households by containing income losses while caring for sick children). Historically, the introduction of new vaccines has been based upon short-term economic decisions, such as health-care costs saved and the national impact of income losses prevented (due to parents caring for sick children), or alternatively on the number of disability-adjusted life years (DALYs) averted,5Deogaonkar R Hutubessy R van der Putten I Evers S Jit M Systematic review of studies evaluating the broader economic impact of vaccination in low and middle income countries.BMC Public Health. 2012; 12: 878Crossref PubMed Scopus (77) Google Scholar but a comprehensive analysis of the benefits of vaccines in the short, medium, and long term would be more realistic in delineating the true societal benefits. Income losses in LICs and LMICs due to LGF have been estimated at US$176·8 billion per birth cohort (or $616·5 billion at purchasing power parity rates), while lost educational attainment corresponds to 69·4 million years.6Fink G Peet E Danaei G et al.Schooling and wage income losses due to early-childhood growth faltering in developing countries: national, regional, and global estimates.Am J Clin Nutr. 2016; 104: 104-112Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar With improvements in the quality of water, sanitation, and hygiene (WaSH)—between 1990 and 2017, diarrhoeal deaths in children younger than 5 years decreased by a substantial 13·3% globally due to improved sanitation alone7GBD 2017 Diarrhoeal Disease CollaboratorsQuantifying risks and interventions that have affected the burden of diarrhoea among children younger than 5 years: an analysis of the Global Burden of Disease Study 2017.Lancet Infect Dis. 2020; 20: 37-59Summary Full Text Full Text PDF PubMed Scopus (72) Google Scholar—an even greater effect on LGF and productivity can be expected. Poor nutrition can impact childhood diarrhoea mortality, and accounted for the greatest number of deaths due to diarrhoea in this age group (69·3%) in the Global Enteric Multicenter Study; likewise, improving nutrition would also lead to a decrease in LGF.8Brander RL Pavlinac PB Walson JL et al.Determinants of linear growth faltering among children with moderate-to-severe diarrhea in the Global Enteric Multicenter Study.BMC Med. 2019; 17: 214Crossref PubMed Scopus (12) Google Scholar For a realistic overview, however, the true contribution of LGF needs to be appreciated in context. Recent evidence from combined data in birth cohort studies in six emerging economies indicates that the first 1000 days of life are particularly important for learning and development, and LGF might affect both schooling attainment and intelligence quotient (IQ) scores during this period.9Poveda NE Hartwig FP Victora CG et al.Patterns of growth in childhood in relation to adult schooling attainment and intelligence quotient in 6 birth cohorts in low- and middle-income countries: evidence from the Consortium of Health-Oriented Research in Transitioning Societies (COHORTS).J Nutr. 2021; 151: 2342-2352Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar However, the effect of early-life stature on schooling and adult IQ is attenuated when controlling for childhood IQ.10Stein AD Adair LS Donati G et al.Early-life stature, preschool cognitive development, schooling attainment, and cognitive functioning in adulthood: a prospective study in four birth cohorts.Lancet Glob Health. 2023; 11: e95-104Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar To realistically ensure that our future generations attain their full educational and economic potential, a multipronged approach that includes vaccination, timely and accurate diagnosis of disease, nutrition, WaSH, and promotion of cognitive stimulation is needed.1Puett C Anderson IV, JD Bagamian KH et al.Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling study.Lancet Glob Health. 2023; 11: e892-e902Summary Full Text Full Text PDF Google Scholar, 10Stein AD Adair LS Donati G et al.Early-life stature, preschool cognitive development, schooling attainment, and cognitive functioning in adulthood: a prospective study in four birth cohorts.Lancet Glob Health. 2023; 11: e95-104Summary Full Text Full Text PDF PubMed Scopus (2) Google Scholar Increasing life expectancy globally combined with a decreasing birth rate in many countries has resulted in a significant shift in the global age distribution from 1990 to 2020, changing the population pyramid into a shape resembling a bullet, and we risk having too few economically active individuals to support the global population of the future. Lest we shoot ourselves in the foot, perhaps we need to reconsider how we regard our children: not simply as the most vulnerable of our society, but to remind ourselves that they are the future health-care workers who will care for us, the engineers and scientists who will further develop new vaccines, WaSH, and diagnostic tools for infectious diseases, the educators and entrepreneurs who will ensure sustainability in economic productivity, and the leaders who would strive for a better world for all. We declare no competing interests. Projecting the long-term economic benefits of reducing Shigella-attributable linear growth faltering with a potential vaccine: a modelling studyLGF is a secondary outcome of Shigella infection and reduction in LGF is not often quantified as a health or economic benefit of vaccination. However, even under conservative assumptions, a Shigella vaccine only moderately effective against LGF could pay for itself from productivity gains alone in some regions. We recommend that LGF be considered in future models assessing the economic and health impacts of interventions preventing enteric infections. Further research is needed on vaccine efficacy against LGF to inform such models. Full-Text PDF Open Access