The Long-Term Success of Mandatory Vaccination Laws After Implementing the First Vaccination Campaign in 19th Century Rural Finland

Abstract

In high income countries, childhood infections are on the rise, a phenomenon in part attributed to persistent hesitancy towards vaccines. To combat vaccine hesitancy, several countries recently made vaccinating children mandatory, but the effect of such vaccination laws on vaccination coverage remains debated and the long-term consequences are unknown. Here we quantified the consequences of vaccination laws on the vaccination coverage monitoring for a period of 63 years (1837–1899) rural Finland’s first vaccination campaign against the highly lethal childhood infection smallpox. We found that annual vaccination campaigns were focussed on children up to 1 year old, but that their vaccination coverage was low and declined with time until the start of the vaccination law, which stopped the declining trend and was associated with an abrupt coverage increase of 20 % to cover >80 % of all children. Our results indicate that vaccination laws had a long-term beneficial effect at increasing the vaccination coverage and will help public health practitioners to make informed decisions on how to act against vaccine hesitancy and optimise the impact of vaccination programmes.

Grandmother presence improved grandchild survival against childhood infections but not vaccination coverage in historical Finns

“…For the purpose of this study, we combined two datasets: (i) a large multigenerational demographic dataset of pre-industrial Finnish families [18] and (ii) vaccination records manually digitized from church records held in Finnish national and provincial archives [36]. The large multigenerational dataset of pre-industrial Finnish families was previously used to identify the beneficial effects associated with grandmother presence on grandchild survival [5,18].…”

“…In brief, the vaccination campaign started in Finland in 1802, but consistent collection of vaccination records with details on the vaccinated individuals became more common around the 1840s, depending on the parish. Although the vaccination campaign faced high hesitancy, the vaccination coverage of children was on average 80% (interannual SD: 22%) during our study period [36]. However, large smallpox epidemics occurred until the mandatory vaccination law was introduced in 1883 after which smallpox prevalence decreased until the last Finnish case was diagnosed in 1941.…”

“…Most individuals were vaccinated within the first 2 or 3 years after birth, with no records of vaccinations of children older than 8 years old. For further details on Finland's vaccination campaign against smallpox, see Ukonaho et al [36]. In brief, the vaccination campaign started in Finland in 1802, but consistent collection of vaccination records with details on the vaccinated individuals became more common around the 1840s, depending on the parish.…”

The epidemic dynamics of three childhood infections and the impact of first vaccination in 18thand 19thcentury Finland

“…For example, mortality due to childhood infections is a driving force behind human reproductive rates and the associated demographic transition (7,8). More recently, historical pandemics, such as the 1918 influenza pandemic, provided lessons for Covid-19 interventions (9) and studying historical vaccination laws can inform the optimization of vaccine implementation in the face of high vaccine hesitancy (10).…”

“…First, we provide a detailed description of the historical epidemic dynamics of three childhood infections smallpox, pertussis and measles in a pre-demographic transition society. Second, Finland introduced annual vaccination against smallpox in 1802, with a strong bias towards children and a coverage starting from approximately 50% in 1812 and rising to 75% in 1850 (10, 13). We use the roll-out of this vaccination programme to test five theoretically expected impacts of vaccination: (i) decreasing mortality, (ii) increasing age at infection, (iii) increasing time between epidemics, (iv) increasing fade-outs, which all result from (v) decreased pathogen transmission (14, 15).…”