Behavioural interventions to increase test uptake and self-isolation compliance during Covid-19 community test pilots in the Netherlands: four population-level randomised control trials.

At the start of 2021, the Dutch Ministry of Health, Welfare and Sport (VWS) set out to assess the implementability, scalability, and uses of open-access community-wide Covid-19 testing of asymptomatic individuals in addition to symptomatic individuals. This approach was piloted in collaboration with regional preventative healthcare services (GGD Flevoland and GGDrU) and two local councils (Bunschoten and Dronten) respectively. As part of these pilots we evaluated the effectiveness of behavioural interventions on test uptake and self-isolation compliance in four randomised controlled trials. For participants in all conditions access to regular care remains. Intervention conditions only offer additional care. If residents do not wish to participate in research, they receive care in accordance with national guidelines.

To increase test uptake, we set out to compare two types of invitation and reminder letters. One incorporating behavioural determinants of Covid-19 testing, the other developed by each local council. We also varied ease of access to testing sites by mobility (Bunschoten), locality (Dronten) and availability of drop in (both). We evaluate their effectiveness by assessing (a)symptomatic test uptake during the 6-week period of the community pilot using a randomised controlled design in both test sites. In addition, all residents of Dronten and Bunschoten were invited to complete a short survey to reasons for partaking, after trial completion.

To increase self-isolation compliance, we examined whether active (requesting consent to hand over their phone number) or passive referral (offering the phone number) to a local wellbeing and support service affected quarantining or self-isolation compliance for (suspected) Covid-19 patients in one site (Bunschoten). In the other site (Dronten), we examined whether a conversation about vs. referral to a self-isolation coping plan identifying barriers for effective self-isolation affected quarantining or self-isolation compliance for (suspected) Covid-19 patients. Both interventions were set out using a randomised controlled design. In addition, the latter site offered a ‘Homestay Sack’ to patients during the first 3 weeks of the intervention period, containing locally relevant information, a locally sourced gift, a symptom-countdown calendar, and other relevant resources to ease the isolation period. All participants were asked to report on their isolation period in a survey after 10 days.

Testing trials:

1. We expect to see a main effect of time on number
a) of tests completed
b) of persons who get tested
c) of tests per person

2. We expect to see a main effect of letter condition. Specifically, we expect that the intervention letter (stressing the importance of testing) compared to the control letter (developed by local council) increase the total number
a) of tests completed
b) of persons who get tested
c) of tests per person

3. We expect to see an interaction effect between the effect of the letters and pilot week, where the difference between intervention and control letters on of
a) of tests completed
b) of persons who get tested
c) of tests per person
changes over time.

4. In Dronten, we expect to see a main effect of test location. To be more precise, we expect that a comparison between two suburban areas Swifterband and Biddinghuizen, where Swifterband (with a local test facility) compared to the Biddinghuizen (without a local test facility) increases the total number
a) of tests completed
b) of persons who get tested
c) of tests per person

5. In Bunschoten, we expect to see an interaction effect between two suburban areas and testweek with alternating presence of a mobile testing facility to show that presence of a mobile testing facility, compared to absence of testing facility increases the total number
a) of tests completed
b) of persons who get tested
c) of tests per person

Self-Isolation support trials:

Bunschoten:
6. We expect to see a difference between referral approaches. Specifically, we expect that active (request to patients to hand phone numbers to the support service, who call) vs passive referral (patients are suggested to call the local support service themselves):
a) Increases the number of conversations between patients and local support service
b) Reduces the number of times patients left the house (excluding for medical needs)
c) Reduces the number of times patients received visitors (excluding for medical needs)

Dronten:
7. We expect to see a main effect of the coping plan referral approach. Specifically, we expect that active walk-through (step-by-step identification of barriers and solutions to the isolation period) vs passive referral (patients are informed of the plan):
a) Reduces the number of times patients left the house (excluding for medical needs)
b) Reduces the number of times patients received visitors (excluding for medical needs).

8. We expect to see a main effect of the Home-Stay bag. We expect to see a trend break between the first and last 3 weeks of the trial period, in
a) Number of times patients left the house (excluding for medical needs)
b) Number of times patients received visitors (excluding for medical needs).
in favour of patients who received the Home stay bag.

Isolation adherence: Day 1, Day 5, Day 10.

1. RCT 1 Test Dronten -
a) IV1: Locality of test sites, two levels: participants have a local testing facility (Swifterbant, intervention) or not (Biddinghuizen, control).
b) IV2: Invitation and reminder letters, two levels: participants receive a letter written by the local council (control letter) or adjusted to reflect behavioural determinants (intervention).

2. RCT 2 Test Bunschoten -
a) IV1: Locality and mobility of test site using a testbus between two boroughs, two levels: mobile testing facility absent (control), mobile testing facility present (intervention).
b) IV2: Invitation and reminder letters, two levels: participants receive a letter written by the local council (control letter) or adjusted to reflect behavioural determinants (intervention).

3. RCT 3 Self Isolation Dronten -
a) IV1: Coping plans to identify potential barriers during self-isolation, two levels: participants receive an email about the coping plan (control) or discuss the coping plan over the phone (intervention).
b) IV2: A Stay-At-Home bag developed to address determinants of self-isolation, two levels: participants are not offered (control) or are offered the bag (intervention).

4. RCT 4 Self isolation Bunschoten -
a) IV1: Referral to local support services, two levels: participants are informed of the service (control) or called by the service (intervention).