How do I check if I've had two MMR doses as an adult?

The Australian Immunisation Register (AIR) holds your vaccination history and is accessible via myGov under the Medicare section. It records vaccinations given since the mid-1990s. If your AIR record shows only one MMR dose, or no record at all, speak with your GP about catch-up vaccination. Adults born before 1966 are generally considered immune through prior natural infection. Adults born between 1966 and 1992 are the cohort most likely to have received only one childhood dose before the two-dose schedule was introduced. If you are unsure, your GP can request a measles serology blood test to confirm your immunity status before vaccinating.

Can I receive the MMR vaccine as an adult if I missed a second dose?

Yes. Catch-up MMR vaccination is available through your GP at any age if you have not received two documented doses. The MMR vaccine is a live vaccine and cannot be given during pregnancy — if you are planning a pregnancy, checking and completing your vaccination status beforehand is worth doing. Two doses of MMR provide around 97% protection against measles. There is no harm in receiving an additional dose if you are uncertain about your history.

Measles 2026: NSW outbreak alert and the adults who missed a dose

What just happened

NSW Health has issued an outbreak alert for measles in inner Sydney — covering Potts Point, Darlinghurst, and the Sydney CBD — with Port Macquarie Base Hospital subsequently identified as an exposure location. The alerts, reported by Medical Republic on 25 June 2026, come as Australia records a significant escalation: 112 measles cases in 2026 to date, a trajectory that puts this year on course to surpass the 2025 record.

This is a follow-up to Australia’s measles resurgence: the post-COVID vaccination gap, published 5 June 2026. That post covered the general resurgence picture and the childhood vaccination gap. This post focuses on the specific 2026 NSW outbreak alert and the less-discussed adult cohort under-immunisation problem.

Australia’s national vaccination coverage for one-year-olds has now dropped to an average of 91.54% — well below the 95% two-dose MMR threshold required for herd immunity. Western Australia records the lowest two-year-old coverage nationally at 89.78%. Five-year-old coverage sits at 93.17%. Every metric is below where it needs to be.

Three factors are driving this, per Professor Adrian Esterman, an epidemiologist who has been tracking the 2026 surge: international travel concentrated through Southeast Asia (34 of 60 NSW cases between January and March 2026 were acquired overseas, nearly all in the region); declining childhood vaccination rates linked to appointment delay and hesitancy; and an under-immunised adult cohort — those aged roughly 20 to 49 — who received only a single MMR dose before Australia introduced the two-dose schedule in 1992.

That third factor tends to receive the least attention. It is worth examining.

The both-and

The adult cohort gap is real and specific

Adults born between approximately 1966 and 1992 are in a particular epidemiological position that most of them do not know about. Before 1992, Australia’s childhood immunisation schedule included a single dose of measles-containing vaccine at 12 months. That year, the schedule moved to two doses — a second MMR was added at 18 months (later revised to 18 months after being four years) — because a single dose left a residual 5% failure rate at the population level that, in a highly contagious virus, is enough to sustain transmission.

One dose of MMR provides around 95% protection against measles. Two doses provide around 97%. The difference sounds small. In the context of a virus with an R0 of 12 to 18 — meaning a single infectious person in a fully susceptible population could infect 12 to 18 contacts — a 2% immunity gap at the individual level translates into meaningful population vulnerability when millions of adults are in that situation simultaneously.

This cohort — now aged roughly 34 to 60 — has not been targeted by the immunisation reminder systems that capture children and pregnant women. They received their one dose decades ago and have had no subsequent immunisation touchpoint to prompt a review. Many of them believe, reasonably, that childhood vaccination covered them. In most cases it did. In a meaningful minority it provided partial but not complete protection — and without checking the Australian Immunisation Register, there is no way to know which group you are in.

The Australian Immunisation Handbook is clear on catch-up: adults without evidence of two MMR doses, documented natural infection, or confirmed immunity on serology are candidates for catch-up vaccination.

Why the outbreak geography matters

Inner Sydney is not a low-density exposure environment. Potts Point, Darlinghurst, and the Sydney CBD are high-footfall areas with significant transient populations — travellers, tourists, event attendees, hostel guests from high-prevalence regions. A hospital exposure site introduces a different category of risk: healthcare workers, patients with compromised immunity from other conditions, and people attending for unrelated care who may have sub-optimal measles protection.

The travel link remains dominant — Southeast Asia has sustained measles circulation, and the RACGP has flagged the travel pattern as the primary import pathway. But the presence of inner-Sydney community exposure sites means the virus is not only arriving at airports; it is moving through local networks where immunity is sufficient to slow but not stop spread.

Dr Vicky Sheppeard’s note to GPs captures the practical point: “If a patient appears with a fever, cough, conjunctivitis, a rash beginning from the face down, the first thing GPs could ask is if they’ve been overseas.” The symptom triad matters because measles is clinically contagious for four days before the rash appears — the window when exposure happens before anyone knows to isolate.

What the data cannot resolve

The three-pronged analysis is epidemiologically sound. What it cannot guarantee is that coverage improvement solves an active outbreak quickly. Coverage improvement works on the scale of months to years, through GP encounters, school programmes, and outreach to families who have fallen out of contact with regular health services. It is a structural intervention, not a rapid-response one.

The active outbreak response is a different pathway: contact tracing, exposure site notifications, and post-exposure prophylaxis (MMR within 72 hours of exposure, or immunoglobulin for immune-compromised contacts). Your GP or the NSW Health line can advise if you believe you have been at an exposure site.

2 cents

If you were born between 1966 and 1992 and are not sure how many MMR doses you received as a child: check your Australian Immunisation Register record via myGov under the Medicare section. If it shows one dose or no record, speak with your GP about catch-up. The vaccine is safe and the conversation is brief.

For parents of children under five: the two-dose schedule is at 12 months and 18 months. If either dose was delayed or missed during the pandemic period, catch-up through your GP is straightforward.

If you have recently been in any of the named inner-Sydney exposure locations, or have returned from travel through Southeast Asia in the past three weeks: be alert for the symptom triad — fever, cough, runny nose, red eyes, then rash beginning at the face and spreading downward. If those symptoms develop, phone ahead before attending a clinic or emergency department. Measles requires infection control precautions that need to be in place before your arrival.

Verdict: yes — worth knowing about.

Sources cited

Medical Republic — Measles outbreaks a three-pronged problem. 25 June 2026. https://www.medicalrepublic.com.au/measles-outbreaks-a-three-pronged-problem/126790
Australian Immunisation Handbook — Measles chapter. https://immunisationhandbook.health.gov.au/contents/vaccine-preventable-diseases/measles
RACGP newsGP — Warning issued as measles cases surge. https://www1.racgp.org.au/newsgp/clinical/warning-issued-as-measles-cases-surge
Services Australia — Australian Immunisation Register. https://www.servicesaustralia.gov.au/australian-immunisation-register