The UK's Vaccine Catch-Up Gap Is a Recall Problem, Not Refusal

MMR coverage in England has not touched the 95% target at any milestone since 2020-21, and measles cases in 2026 have already overtaken the whole of 2025 with two children dead. Almost none of this traces back to parents refusing the vaccine — it traces back to a catch-up dose that was never rebooked once the child’s slot slipped past the recommended window.

Where MMR coverage in England actually sits

The most recent full-year figures from NHS England are not close to reassuring, and they were already the worst on record before this year’s measles surge made the consequence visible. MMR1 coverage at 24 months fell to 88.9% in 2023-24, the lowest level since 2009-10. MMR2 at age five, the dose that actually closes a child’s protection, fell further still, to 83.9% — again the lowest since 2009-10. Across all fourteen vaccine measures NHS England tracks, coverage moved in one direction that year: down.

The 95% figure isn’t a stretch target set by an optimistic committee. It’s the coverage level generally accepted as the point at which a highly transmissible disease such as measles struggles to find enough susceptible children to spread between them — below it, outbreaks stop being a hypothetical. NHS England’s own note on the 2023-24 release is blunt about how long the country has been under that line: no vaccine on the schedule met 95% that year, and the last one that did was the 5-in-1 at age five, back in 2020-21.

The gap tracks timing and geography, not straightforward refusal

One detail in the coverage figures is easy to skim past and it’s the one that matters most for a surgery deciding what to do about it: MMR1 coverage climbs from 88.9% at 24 months to 91.9% by age five. That’s not a new cohort of parents changing their minds three years later — it’s largely the same children, caught up late, after the window NHS guidance actually recommends had already closed. The gap between “on schedule” and “eventually done” is where a practice’s own effort either shows up or doesn’t.

That regional spread — 72.0% in London against 83.0% in the South West for the same monthly cohort — isn’t explained by vaccine hesitancy sorting itself neatly along a map. Population churn, families new to a practice’s list, appointment availability and how hard a surgery works its own overdue list all vary by area in ways refusal doesn’t. A borough with more families moving between GP registrations in their child’s first year is a borough where a recall letter posted to a last-known address has more chances to miss.

Measles is testing the theory in real time

The bet that a gap this size wouldn’t matter clinically has not paid off. UKHSA confirmed 801 laboratory-confirmed measles cases in England between 1 January and 22 June 2026 — already close to the 959 recorded across the whole of 2025 — and two of those cases were children who died. Sixty per cent of this year’s cases are in children aged ten and under, concentrated around London and the West Midlands, which lines up precisely with where first-dose coverage is weakest. The Health Secretary’s message alongside the June figures was that the MMR vaccine “remains the best protection” against the disease, and UKHSA’s advice for anyone who has “missed out on their measles vaccines” is that they can still catch up. Both statements are true. Neither one gets a specific overdue child rebooked.

NHS England has responded by confirming a 2026/27 vaccination catch-up campaign focused specifically on MMR, driven by this year’s outbreaks and the loss of the UK’s WHO measles elimination status. A national campaign sets the direction and the funding; it does not, on its own, look up which children on a given surgery’s list are overdue and get them a slot. That part still has to happen one patient at a time, inside the practice.

Why the recall list rarely gets worked the way guidance says it should

UKHSA’s own toolkit on immunisation inequities describes what effective catch-up outreach is supposed to look like: “systematic invitations and reminders, escalating contact where needed” — not a single letter and a shrug if nobody replies. That’s the standard. It’s also, in most surgeries, the first thing to slip when the same reception team is also answering the phone for same-day bookings, chasing prescription queries and working through everything else that lands on the desk that morning.

The practical result is a recall process that runs in bursts rather than continuously. A batch of letters goes out ahead of a school-entry check or a local outbreak; whoever calls back gets an appointment; whoever doesn’t hear back, or has moved house since the address on file was last updated, drops off the list until the next push. There’s rarely dose-level targeting in that approach — a family with one overdue jab and a family with three tend to get the same generic reminder, and a non-responder rarely gets a second attempt through a different channel before the list moves on to the next task.

None of that is a criticism of any individual practice. It’s what happens when a genuinely good policy — call and recall, run properly, is one of the best-evidenced ways to close a coverage gap — competes for the same finite reception hours as everything else a surgery has to do that day, and loses, because the parent ringing about a same-day appointment is the one actually on the phone right now.

The cost of that trade-off isn’t only the population-level outbreak risk described above, which sits above any single practice’s control. There’s a more immediate one, sitting quietly in the appointment book: a child who is overdue for MMR has usually also missed the developmental check, the growth review or the general conversation with a GP that would normally happen alongside it. A family that has drifted off the vaccination list is often a family drifting away from the practice relationship altogether, and by the time a stale recall list finally gets worked — ahead of a school-entry deadline, say, or after a local case makes the news — some of those families have moved house, changed number or registered elsewhere. The contact attempt fails before it starts, on top of the dose that was already missed. Every one of those slots is also, less dramatically, a bookable appointment that never gets booked — capacity the surgery already has, going unused because nobody reached the family in time to fill it.

What proactive recall looks like in a surgery

The fix doesn’t need a new clinical protocol. The schedule, the catch-up eligibility rules and the national campaign already exist. What’s missing is the follow-through — the unglamorous, repetitive, time-sensitive work of checking who’s overdue and closing the loop with that family before the gap widens into a missed year, not a missed month. That’s exactly the kind of continuous, high-volume outreach an AI voice and WhatsApp agent can run without waiting for a quiet afternoon that never quite arrives.

1. 1
   Flag overdue children automatically

   Cross-reference the practice list against the immunisation schedule by age and dose, not by whether a booking already exists — most overdue children have no appointment pending at all.

2. 2
   Make contact the same week the gap opens

   An AI agent places the call, sends the text or opens a WhatsApp message as soon as a child crosses into overdue territory, rather than waiting for the next scheduled recall round.

3. 3
   Offer a real slot straight away

   The message carries an actual bookable time against the surgery's live diary, so a parent can confirm on the spot instead of being asked to ring back during opening hours.

4. 4
   Confirm again closer to the date

   A reminder the day before cuts the risk that the newly booked catch-up appointment itself becomes a no-show.

5. 5
   Escalate anyone who stays quiet

   A family who doesn't respond to a text gets a call; a family who doesn't answer a call gets a WhatsApp message — instead of falling off the list after a single unanswered attempt.

None of this replaces clinical judgement — a GP or practice nurse still decides what’s appropriate for a given child, and the disclaimer below still applies in full. What changes is that the administrative half of catch-up, finding who’s behind and getting them back through the door, stops depending on whether reception happened to have a spare half hour that week. Arbol runs that outreach as a standing process across a surgery’s whole paediatric list: identifying who’s overdue against the schedule, contacting them by phone, text or WhatsApp, offering a bookable slot, confirming it nearer the date, and escalating anyone who goes quiet — the systematic, escalating contact UKHSA’s own guidance describes, running every week rather than in the occasional catch-up drive a stretched team can find time for.

If your surgery is trying to close this gap ahead of the 2026/27 catch-up campaign, the same operating model — proactive contact instead of a waiting room that only fills when a parent remembers — sits behind how Arbol works. Seeing the family, and the missed dose, before the outbreak does is the whole point.