Evaluating the Long-Run Socioeconomic Effects of Childhood Vaccination

Project Information

Valvax

Grant agreement ID: 890475

DOI

10.3030/890475

Project terminated on 11 June 2022

EC signature date 4 March 2020

Start date 1 January 2021

End date 31 December 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 207 312,00

EU contribution

€ 207 312,00

Coordinated by

SYDDANSK UNIVERSITET
Denmark

Periodic Reporting for period 1 - Valvax (Evaluating the Long-Run Socioeconomic Effects of Childhood Vaccination)

Reporting period: 2021-01-01 to 2022-12-31

Summary of the context and overall objectives of the project

This MSCA research project “Quantifying the Long-Run Social Value of Childhood Vaccination” (Valvax) combines research in the fields of economics and clinical sciences to ask the overarching research question: What are the long-run social benefits attributable to early childhood access and experience with vaccines? To answer this question, I use the historical 1954 Salk polio vaccine trial and detailed individual-level microdata to study the socio-effects of childhood vaccination. With over 1.8 million child participants ages 6-10, the Salk trial is the largest medical trial ever conducted.

The development, procurement, and provision of vaccines rely on public investment and government support. Undervaluation of vaccines and their long-run socioeconomic effects could result in suboptimal investment in this crucial foundation of public health. Furthermore, lack of evidence regarding long-term non-specific effects is one of the main concerns among the growing number of “vaccine-skeptics.” Using the context of the 1954 Salk vaccine trial, this project explores how such temporary expansions in healthcare provision can reverberate across time and affect public health more broadly than just reducing the incidence of the targeted disease.

The goals of this project are to study how the Salk Vaccine trial of 1954 affects the provision of health services in a time and place where governments provide few if any healthcare services. This effort includes examining how a transitory vaccine trial influenced uptake in polio vaccines over the 1950s, the likelihood that places participating in the trial hosted vaccine clinics or organized large-scale public vaccination efforts, and the effects on mortality patterns.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

1) Overview of work performed
We have completed one project and have preliminary results for the second project undergoing review by the U.S. Census Bureau. The first project is currently being revised and is accepted at multiple conferences. We have also had success in my research uncovering archival records that can enhance the impact of the research. These archival records include the Salk Papers hosted at the University of California San Diego and Records Group 90 of the Public Health Service detailing the U.S.'s polio eradication campaign hosted at the National Archives at College Park, MD.

2) Research Undertaken
a. Project I: Mass Vaccination and Mortality: Evidence from the US’s Experience with the 1954 Salk Vaccine Trial

This project uses difference in differences to study how trial participation affects the evolution of mortality in U.S. counties that received the trial relative to those that did not receive the trial. I find statistically significant declines in all-cause mortality in trial counties relative to non-trial counties (counties with population between 50,000 and 200,000 residents) after 1955. These declines increase in 1963 with the passage of the Vaccine Assistance Act, which provided permanent federal funding for vaccine purchases and the licensing of the trivalent oral polio and measles vaccines. Evidence from newspapers and archives suggest that counties more proximate to trial counties were more likely to host public vaccine clinics during the 1955-1957 polio eradication campaign and in 1963/1964.

b. Project II: Effects of Trial Participation on Long Run Outcomes

This project links individuals by birthplace and date of birth to the Salk trial to study outcomes later in life. We use differences in differences to study how proximity to trial participation affects later life disability, income, educational attainment, and labor force participation. We compare persons who were more proximate to Salk trial participation in age (target group was 6-10) and geography (trial county verses counties with population between 50,000 and 200,000 residents that was not in trial.) I control of birth cohort and birthplace fixed effects, thus the identification comes from comparing persons slightly older and younger who were also born within the same county. Preliminary results suggest that there are large statistically significant reductions in reported disability and increases in income among women who were more likely to have participated in the trial.


3) Dissemination

Past invited presentations
- Western Economic Association International 2021 Economic History Association/Cliometric Society Sessions, 2021 online
- Pandemics in Economic History: Thu March 10th, Online World Economic History Congress Preconference online
- HEDG 11th annual growth workshop, Conflict and Development, Odense, April 28-29, 2022
- Ninth Center for Economic and Policy Research, Economic History Symposium, Odense June 9-10, 2022
- Economic History Association Annual Meeting 2022, La Crosse, Wisconsin, September 16-18, 2022.

Currently invited presentation

- Southern Economic Association Meetings, Economic History Association/Cliometric Society Sessions, November 19-22, 2022
- ASSA Annual meetings, Alliance for Social Science Associations, Economic History Association/Cliometric Society Sessions. January 6-8, 2023

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

What is the societal impact of large-scale vaccination efforts? Do transitory expansions in the public provision of health services expand future provision of public health services? While the direct benefits of herd immunity and reductions in infectious disease are well studied, researchers have not studied the potential long-run effects of increased vaccine coverage on socioeconomic outcomes. Furthermore, economic historians have not studied the Salk trial and its effects. Economists have established a strong connection between early childhood health and measures of economic wellbeing later in life. Clinical medical researchers have found that vaccines can broadly affect overall health.

Using historical expansion in vaccine access, this project highlights some of the potential long-run benefits of these logistical efforts and expansions in the provision of health services. We use the largest vaccine trial in human history, the 1954 Salk Inactivated Polio Vaccine (IPV) trial, to study how such vaccination efforts can influence the ability of governments to provide vaccines in the future. In the United States in the 1950s, governments provided limited public health services, and vaccines were the provided primarily through private purchases through personal family physicians.

By comparing areas that received the trial and those that did not, this investigation allows us to explore how a short-term expansion in vaccine access affects longer run public provision of vaccines and the uptake of said vaccines. This context also allows us to explore how expanded vaccine access broadly affects health patterns in a period before large scale Federal programs such as the Vaccine Assistance Act, Medicare, and Medicaid. This research project reveals that areas that participated in the Salk IPV trial were more likely to host public vaccination clinics and pursue mass vaccination efforts in the years after the trial that locations that did not participate. This research finds that states where more people participated in the trial had much greater per capita uptake of the IPV by 1960 than states with less participation. Finally, this project finds that trial participation is associated with reductions in all-cause and infant mortality, and these declines in mortality coincide with U.S. Federal funding for childhood vaccination.

Map of US Counties in 1954 Salk Polio Vaccine Trial: Author's Tabulation

Polio morbidity in the US: Author's Tabulation

Map of US Counties in 1954 Salk Polio Vaccine Trial: Author's Tabulation

Timeline of Key Health Events Surrounding the 1954 Salk Polio Vaccine Trial