Implementing Germ Defence digital behaviour change intervention via all primary care practices in England to reduce respiratory infections during the COVID-19 pandemic: an efficient cluster randomised controlled trial using the OpenSAFELY platform

Table 2 Controlled interrupted time-series estimates assessing intervention-related changes

	1. Change at time of intervention		2. Change in trend following intervention
Outcome	Rate ratio (95% CI)	p-value	Rate ratio (95% CI)	p-value
RTIs	1.02 (1.00, 1.05)	0.10	0.97 (0.93, 1.02)	0.24
Acute RTIs	1.02 (1.00, 1.05)	0.09	0.98 (0.93, 1.02)	0.26
Gastrointestinal infections	1.06 (0.96, 1.17)	0.28	0.95 (0.80, 1.13)	0.57
COVID diagnoses	1.03 (0.99, 1.08)	0.14	1.11 (1.02, 1.20)	0.02
COVID symptoms (sensitive)	1.00 (0.95, 1.05)	0.98	1.04 (0.96, 1.13)	0.32
COVID symptoms (specific)	1.03 (0.94, 1.13)	0.46	0.98 (0.84, 1.13)	0.82
Antibiotic use	1.00 (0.99, 1.01)	0.66	1.01 (0.99, 1.03)	0.22
Hospital admissions	1.00 (0.99, 1.01)	0.62	1.00 (0.98, 1.01)	0.64

Estimates for changes in trend represent relative change in rate over the 17-week post-intervention period compared to the pre-intervention period. Both estimate types adjusted for any background changes in the control group

ISSN: 1748-5908