Pay-it-forward intervention increased pneumococcal vaccine uptake among older adults in China: a randomized controlled trial

TL;DR

A pay-it-forward cost-sharing program significantly increased pneumococcal and flu vaccine uptake among older adults in China compared to standard self-paid options.

Contribution

This study introduces and evaluates a novel pay-it-forward intervention to improve vaccine uptake in older adults.

Findings

The pay-it-forward group had a 70.9% pneumococcal vaccine uptake versus 13.5% in the standard-of-care group.

Participants in the pay-it-forward group showed higher vaccine confidence and lower economic cost per vaccination.

The intervention also increased influenza vaccine uptake and successful vaccine referrals.

Abstract

Pneumococcal vaccination reduces morbidity and mortality among older adults, yet coverage remains suboptimal in China. This study aimed to assess the effectiveness of a pay-it-forward intervention (covering two-thirds of the pneumococcal vaccination cost and offering the option to donate) in increasing pneumococcal vaccination among older adults (aged 60 years or older) in China, compared to standard-of-care self-paid vaccination.

We used block randomization (block size = 4) to assign participants to a pay-it-forward arm and a standard-of-care arm in a 1:1 ratio. The primary outcome was pneumococcal vaccination. Secondary outcomes included influenza vaccine uptake, vaccine confidence, successful vaccine referral, and cost-effectiveness. Logistic regression analysis was used to compare PPSV-23 and influenza vaccination coverage and vaccine confidence between the two groups. The cost-effectiveness of the interventions was assessed using a micro-costing approach from the healthcare provider’s perspective.

From January to September 2024, 221 older adults were randomized (110 in the pay-it-forward group and 111 in the standard-of-care group). Pneumococcal and influenza vaccine uptake were significantly higher in the pay-it-forward arm (70.9% and 30.0%) than in the standard-of-care arm (13.5% and 17.1%), with adjusted odds ratios of 17.20 (95% CI, 8.39–37.60) and 2.29 (95% CI, 1.17–4.65). The pay-it-forward group also exhibited greater confidence in the safety (4.29, 95% CI, 1.78–11.50), importance (5.15, 95% CI, 2.05–14.60), and effectiveness (7.14, 95% CI, 2.36–27.50) of the vaccine than that in the standard-of-care group. The pay-it-forward group had a higher successful vaccine referral rate (15.5% vs. 10.8%) and had a lower economic cost per person vaccinated (US $95.67 vs. US $278.56) compared with the standard-of-care arm.

Our findings demonstrate that the pay-it-forward intervention significantly enhances pneumococcal and influenza vaccination coverage and improves vaccine confidence among the older adults. This study highlights the potential of the pay-it-forward intervention as an effective means to boost health service utilization.

2024–01-03, Chinese Clinical Trial Registry, ChiCTR2400079410.

The online version contains supplementary material available at 10.1186/s12916-026-04624-2.

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