How the COVID-19 pandemic and cost-of-living crisis shaped reach and engagement in the ECAIL trial targeting socially disadvantaged families: an interdisciplinary implementation study

This interdisciplinary implementation study demonstrates that the ECAIL childhood obesity prevention trial successfully maintained its reach and acceptability among socially disadvantaged families in France despite the disruptions of the COVID-19 pandemic and cost-of-living crisis, thanks to adaptive strategies like the rapid resumption of home-based visits and flexible implementation approaches.

The Gist

Imagine the ECAIL trial as a specialized support club for expectant mothers in France who are facing tough times financially or socially. The club's goal is to help these families build healthy habits for their babies before they are even born and during their first two years of life. The "coaches" for this club are dietitians who visit the families right in their own homes.

However, just as the club was getting into a rhythm, two massive storms hit: the COVID-19 pandemic (which forced a six-month shutdown) and the cost-of-living crisis (which made food and rent much more expensive).

This paper is like a report card on how the club survived these storms. Here is what happened, explained simply:

1. The "Eligibility" Pool Got Bigger (The Storm Made More People Need Help)

Before the pandemic, about 30% of the pregnant women screened for the club qualified because they were struggling. After the pandemic and the cost-of-living crisis hit, that number jumped to 33.6%.

• The Analogy: Think of the eligibility criteria as a lifeboat. Before the storm, the lifeboat was full of people who were already in rough waters. When the hurricane (pandemic) and the rising tide (inflation) hit, more people found themselves in the water, so the lifeboat had to take on more passengers. The study found that more families were struggling with things like not having a steady job, feeling socially isolated, or finding it hard to pay for food and rent.

2. The "Sign-Up" Rate Stayed Steady (The Club Didn't Lose Its Members)

Even though the world was chaotic and the families were under more pressure, the percentage of eligible women who actually said "yes" to joining the club stayed exactly the same (about 24.6%) before and after the shutdown.

• The Analogy: Imagine a gym that closes for six months due to a lockdown. When it reopens, you might expect people to be too tired or too busy to come back. But in this case, the "gym" (the home visits) was so valuable that the same number of people signed up as before. In fact, the women who signed up after the pandemic were often even more eager because they were lonely and missed the social connection.

3. The "Coaches" Adapted Their Game Plan

When the club reopened, the dietitians (the coaches) had to wear masks and check for COVID symptoms before visiting. They also started calling ahead to make sure no one was sick before driving to a house.

• The Analogy: Think of the dietitians as delivery drivers. Before the storm, they just dropped off a package. After the storm, they had to wear hazmat suits and check the weather report before driving. Surprisingly, these new rules didn't scare people away. In fact, the new "check-in" calls actually reduced the number of times the dietitians drove to a house only to find no one there. It was like a GPS update that saved them from wasted trips.

4. The "Home Visit" Was the Secret Weapon

The study found that the most important thing was that the dietitians kept visiting families in their homes. They didn't switch to video calls or phone-only check-ins.

• The Analogy: During the lockdown, families felt trapped in their apartments, isolated from the world. When the dietitians finally came back to knock on the door, it wasn't just about nutrition advice; it was a lifeline. The dietitians reported that the mothers were "glad to see people again." The home visit acted like a warm blanket for families who were feeling cold and isolated.

5. The "Hard-to-Reach" Families Were Actually Reached

One of the biggest challenges in public health is finding and keeping "hard-to-reach" people (those who are very poor, isolated, or unstable). The study showed that even though the world was falling apart, this specific program managed to keep its reach strong.

• The Analogy: Usually, when a storm hits, the people on the edge of the cliff (the most vulnerable) are the first to fall off. But this program built a sturdy railing. By keeping the human connection (face-to-face visits) and being flexible with the rules, they kept the most vulnerable families safe and engaged.

The Bottom Line

The paper concludes that when you have a program that is built on trust and flexibility, it can survive even the biggest disruptions. The pandemic and the cost-of-living crisis made life harder for these families, but they didn't stop the program from working. In fact, the program became even more important because it provided a rare moment of human connection and stability in a very unstable world.

What the paper does NOT say:

• It does not claim that this program cured obesity or fixed poverty. It only looked at whether families could join and stay in the program during the crisis.
• It does not suggest that all medical trials should be done this way, only that this specific, co-designed approach worked well for this specific group of people.

Technical Summary

Technical Summary: How the COVID-19 Pandemic and Cost-of-Living Crisis Shaped Reach and Engagement in the ECAIL Trial

Problem Statement
Public health interventions targeting socially disadvantaged populations often face challenges in reach, engagement, and retention. These challenges are exacerbated during periods of major contextual disruption, such as the COVID-19 pandemic and the subsequent cost-of-living crisis. While numerous studies have documented the pandemic's impact on health behaviors and obesity, there is a critical gap in understanding how such large-scale disruptions affect the implementation of ongoing public health interventions, particularly regarding reach, adoption, and fidelity. The ECAIL trial (prEgnanCy and eArly Childhood nutrItion triaL), a multicomponent childhood obesity prevention program targeting socially vulnerable families in northern France, experienced a six-month suspension in 2020 due to national lockdowns. This study investigates how eligibility, participation, and implementation processes were shaped by the pandemic and the ensuing economic crisis.

Methodology
The study employed an interdisciplinary implementation science approach, utilizing a mixed-methods design based on the RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) framework.

• Quantitative Component: The authors analyzed data from 5,744 eligibility questionnaires distributed at the Lille University Hospital maternity ward between March 2017 and April 2023. The analysis compared two distinct periods: the prepandemic phase (P0: March 2017–March 2020) and the post-resumption phase (P1–P3: September 2020–April 2023). Key metrics included eligibility rates, participation rates, distribution of social vulnerability indicators (e.g., receipt of benefits, financial hardship, precarious housing, social isolation), and follow-up completion rates (skipped vs. failed visits). Statistical comparisons were made using two-sided $\chi^2$ tests.
• Qualitative Component: To capture implementation experiences, a focus group was conducted in May 2023 with six dietitians who delivered the intervention. The session was recorded, transcribed, and analyzed thematically to explore adaptations, stakeholder engagement, and perceived mechanisms influencing reach and acceptability during and after the crisis.
• Intervention Context: The ECAIL trial involves screening pregnant women for social vulnerability, followed by home-based nutritional counseling and facilitated access to healthy foods until the child's second birthday. During the pandemic, the protocol was adapted to include pre-visit telephonic COVID-19 risk assessments, mandatory mask-wearing, and strict hygiene protocols, while maintaining in-person home visits rather than shifting to remote delivery.

Key Results

• Eligibility and Reach: The eligibility rate increased significantly from 29.7% in the prepandemic period to 33.6% post-resumption ($P=0.002$). The distribution of social vulnerability criteria remained largely consistent, though the proportion of women reporting that employment was not the main household income source was highest immediately post-resumption (P1). Notably, women ineligible for the trial despite meeting vulnerability criteria showed worsening housing instability and social isolation post-resumption.
• Participation: Participation rates among eligible women remained stable overall (24.6%) across both periods. However, participation fluctuated slightly, rising in P1 and P2 before declining in P3 to levels below the prepandemic baseline. Women who participated were more likely to report perceived financial hardship and to have received study information in person rather than by telephone.
• Implementation and Follow-up: The rate of skipped visits remained low (2.0%) and unchanged between periods. Crucially, the rate of failed visits (dietitians arriving to find no one home) decreased significantly post-resumption (1.7%) compared to prepandemic (4.9%). Qualitative data attributed this improvement to the introduction of pre-visit telephone screening for COVID-19 symptoms.
• Stakeholder Engagement: Qualitative findings revealed that dietitians maintained "proactive relational continuity" via phone and newsletters during the suspension, which facilitated immediate re-engagement upon resumption. Both dietitians and participants expressed relief and enthusiasm at the return of home visits, which were perceived as vital for alleviating social isolation. The hospital prioritized the ECAIL trial over other studies due to the vulnerability of its target population.

Key Contributions

1. Resilience of Home-Based Interventions: The study demonstrates that a complex, home-based intervention targeting socially disadvantaged families can maintain reach and acceptability despite major contextual disruptions, provided that adaptive implementation strategies (e.g., pre-visit screening, maintaining relational contact) are employed.
2. Impact of Crises on Vulnerability: The research provides empirical evidence that successive health and economic crises expand the pool of eligible individuals for social support interventions, reflecting a deepening of pre-existing vulnerabilities (e.g., housing precarity, financial hardship) rather than a fundamental shift in the nature of the target population.
3. Implementation Mechanisms: The study highlights the critical role of "relational work" (maintaining contact during suspension) and face-to-face information delivery in sustaining engagement with "hard-to-reach" populations. It also identifies the utility of pre-visit risk assessments in reducing logistical failures (missed appointments).
4. Methodological Triangulation: By combining quantitative implementation metrics with qualitative insights from frontline staff, the study offers a comprehensive view of how external shocks influence intervention delivery, moving beyond effectiveness outcomes to examine the processes of reach and adoption.

Significance and Claims
The authors claim that their findings illustrate the robustness of co-created, context-sensitive interventions when supported by flexible implementation strategies. The study suggests that the "second health emergency" (the cost-of-living crisis) has intensified social vulnerabilities, necessitating resilient intervention designs.

The paper posits that the collaborative foundations of the ECAIL project allowed for sustained engagement by healthcare providers (HCPs) and participants despite increased workloads and organizational strain. It concludes that home visits and one-to-one interactions are not only effective for reaching vulnerable families but also serve as a mechanism to mitigate social isolation. The authors emphasize that these insights are particularly relevant in a global context of rising poverty and geopolitical instability, arguing that interventions designed with stakeholders and target populations can remain effective even under severe external pressure. The study does not claim to have solved the issues of poverty or obesity but rather provides evidence on how to maintain the delivery of such programs during crises.