Choose a fallback time that works for your practice.
What is changing?
From 23rd September, you'll be able to send individual patient messages via the NHS App, as well as SMS and email.
This is a highly requested feature, built with the NHS over the past 18 months. It gives patients all their healthcare messages in one place, and gives practices the chance to reduce SMS fragment costs.
Not all patients use the NHS App yet, so there's a safety net: if a patient doesn't have the app downloaded or notifications turned on, the message goes straight to SMS. If they do have the app but haven't read the message within your chosen fallback time (e.g. 15 minutes), we'll automatically send it as a text too.
Admins can set the fallback time (15, 30, 45, or 60 minutes) to suit how the practice works and what's best for your patients.
Choosing your fallback time
There's no single "right" fallback time - it depends on what matters more for your practice and your patients:
If your practice relies on fast turnaround for time-sensitive messages (e.g. same-day bookings, urgent triage responses), a shorter fallback time reduces the risk of a delayed response, at the cost of lower fragment savings.
If cost savings are the priority and your messages aren't time-critical, a longer fallback time gives patients more opportunity to read and act on the NHS App message before an SMS is sent.
Admins can enable the feature and set fallback time from workspace settings - see Accurx Desktop: Sending individual messages via the NHS App for how to change this.
This article sets out the pilot results, so you can make an informed choice when deciding whether to enable the feature and how to set your fallback time.
Individual messages: Response Rates
We ran a 12-week pilot across 1,211 practices, comparing a control group (SMS only) against a treatment group (NHS App, with SMS fallback at a fixed 60 minutes).
The graphs below isolate the patients who actually received their message via the NHS App (roughly a third of patients in the treatment group had the NHS App downloaded with notifications on) and compares them against SMS.
Note: This excludes patients whose messages fell back to SMS immediately because they didn't have the NHS App or notifications on - those patients are counted against SMS, not the NHS App, since their experience is identical to SMS-only.
Each bar shows the response rate over one hour, at which point messages that have not been read fall back to NHS.
What this shows:
Between 15 - 60 mins, the response rate slows over time, with control and treatment following the same trend.
In the first hour, SMS consistently gets a faster response than the NHS App.
We also saw response rates recover after the fallback SMS was sent at 60 minutes for all message types.
NHS App read rate over time
Separately from the message-specific response rates above, we also measured how quickly patients read their message once it reached the NHS App.
Fragment cost savings
What the pilot measured, at 60 minutes
During the pilot (with a fixed 60-minute fallback), 8.3% of individual messages were successfully delivered and read via the NHS App before a fallback SMS was needed — meaning no fallback fragment cost was incurred for those messages.
This was an average saving of £95 per practice over the 12-week pilot.
Projected annually, that's approximately £412 per practice per year.
Modelled estimate at alternative fallback times
How we worked this out
This is a modeled estimate, based on:
How quickly patients read messages in the NHS App (from the pilot)
How many patients currently have the App with notifications on (31%)
How many individual message fragments practices send in England each year (around 467 million)
Fragment cost of £0.0225
We used these to estimate what share of messages get read via the App before a fallback SMS would be needed, then worked out the fragment cost saved from those messages - split across England's 6,220 practices to get a per-practice figure.
FAQs
Does this data apply to Batch Messages and Appointment Reminders too? No - this pilot and the figures in this article are specific to individual messages. Batch Messages and Appointment Reminders already route via the NHS App by default, with no fallback-time choice.
Why is the longest fallback option 60 minutes? The range of fallback times was informed by how quickly patients read and responded to messages during the pilot.
Across Self-Book, Message with Reply and Questionnaires, the majority of patients who respond do so within the first 15 minutes, with response rates declining sharply thereafter. NHS App read rates follow the same pattern: 37.5% of messages are read within 15 minutes, but by the 45–60 minute mark, each additional 15 minutes adds only around 3% more reads, falling below 1% per 15-minute window after 2 hours. A significantly longer fallback would therefore capture relatively few additional patients - it would primarily extend the wait for those who were unlikely to see the NHS App message.
If you have any further questions or feedback, please get in touch with our support team using the message bubble in the bottom right-hand corner of this page 👉