A plain-language look at recent autism research and news, gathered from trustworthy sources.

In short: This edition covers a very large U.S. study on the timing of the MMR vaccine and autism, a newly proposed research definition of “profound autism” and why the label is contested, what the evidence says actually helps autistic adults, and early results from a new program for families planning the move into adulthood. We explain each in everyday language and link to the original sources so you can read more.

Not medical advice. This roundup shares research and news for general information only. It is not a diagnosis or treatment plan. For decisions about you or someone you support — including decisions about vaccines or any other medical care — talk with a qualified health professional who knows your situation.

A note on region: Autism Who Knew serves families in the USA and the Caribbean. Research findings reflect the country where the study was done. Where a study is based in one country or region, we say so, because services, costs, and diagnosis rates differ from place to place.

A very large U.S. study on MMR timing and autism

One of the questions families ask us most often is about vaccines. A study published online ahead of print in the Pediatric Infectious Disease Journal on July 28, 2026 looked at one specific version of that question in a very large group of American children.¹

The researchers used Cosmos, a nationwide U.S. electronic health record database, and followed 2,560,035 children who had records linked to a birth parent, up to age 8.¹ They asked whether the age at which a child got their first MMR (measles, mumps, rubella) shot — anywhere between 11.5 and 24 months — was linked to a later autism diagnosis.

What they found:

• Children who got their first MMR dose earlier in that window were no more likely to be diagnosed with autism than children who got it later. The adjusted hazard ratio was 0.97 (99% confidence interval 0.91 to 1.03) — in plain terms, no difference the study could detect.¹
• The same near-zero result held across every age window they tested.¹
• As a check on their own method, the researchers ran the identical analysis on a vaccine nobody has linked to autism — the pneumococcal booster given at 12 to 15 months. It gave a near-zero result too (1.01, 99% CI 0.99 to 1.04), which is what you would expect if the method is working rather than producing false reassurance.¹

Be clear about what this study did and did not test. It compared earlier versus later first doses within the recommended window. It did not compare vaccinated children with unvaccinated children. That separate question has been studied before — most notably in a Danish study of 657,461 children published in Annals of Internal Medicine in 2019, which compared MMR-vaccinated with MMR-unvaccinated children and found a hazard ratio of 0.93 (95% CI 0.85 to 1.02), again no increased risk.²

Why it matters: If you have wondered whether getting the shot “too early” matters, this is a very large U.S. study of that exact question, and it found nothing. It cannot tell you what is right for your own child — vaccine timing can depend on health conditions, travel, and local outbreaks — so bring the question to your child’s clinician. If you are newly navigating all of this, start with What Is Autism? A Plain-Language Guide.

If you look this up on the CDC’s website. CDC’s vaccine-safety page on autism was rewritten in July 2026 and now says the statement “vaccines do not cause autism” is “not an evidence-based claim.”³ Two things are worth knowing about that change. It was made under the Data Quality Act, a rule about how federal agencies word the information they publish, and the page points to no study finding that MMR causes autism. And in its own section on MMR, the same page says that reviews by the Institute of Medicine and the Agency for Healthcare Research and Quality “maintain with a high strength of evidence that there is no association with autism spectrum disorders based on observational evidence only.”³ The page’s broader argument is that no study can rule out the possibility that a vaccine causes autism in someone — which is true of almost any medical question. We report what the peer-reviewed studies above measured, and we link them so you can read them yourself.

“Profound autism”: a proposed research definition, and why the label is contested

You may have seen the term profound autism in the news. The term was first proposed in 2021 by a Lancet Commission, to draw attention to autistic people whose support needs are lifelong and round-the-clock; researchers then used widely varying criteria for it, which is why competing definitions exist at all.⁴ A paper in the open-access journal Molecular Autism (published June 30, 2026) proposed a standard definition for researchers to use.⁴

The authors ran a structured consensus process (a “modified Delphi” study) with more than 70 participants — researchers, caregivers, autistic people, and clinicians. After two rounds of voting, 76% agreed on this research definition: a person who is at least 8 years old, has an autism diagnosis, has adaptive functioning well below age level, requires adult supervision to ensure their physical and mental health, safety, and well-being, and has either an IQ score below 50 or does not communicate verbally beyond single words or fixed phrases used mainly to meet basic needs.⁴

Its authors include clinicians and researchers from Boston Children’s Hospital, UCLA, and Boston University, together with representatives of two organizations that advocate for the term: the Profound Autism Alliance and the Autism Science Foundation.⁴

The authors are explicit about the limits of their own work: the definition is meant for research, and differences in access to testing and services around the world “limit the utility of this definition outside research practices.” Their final round had 78 respondents (a 58% response rate) who were “overwhelmingly composed of respondents from the United States.”⁴

How many children does it describe?

A second study shows how hard that definition is to apply in the real world. In a report published in the Journal of the American Academy of Child and Adolescent Psychiatry on October 2, 2026, CDC researchers looked at 7,084 eight-year-olds with autism across 13 U.S. surveillance sites in 2022.⁵

The report applies what it calls the “updated (2025)” profound autism definition. Its criteria — an IQ below 50 or nonverbal/minimally verbal communication, plus adaptive functioning well below age level — match the research definition above, though the report does not cite the Molecular Autism paper by name.⁵

• The records needed to decide whether a child met the definition were missing almost half the time: IQ data was available for 61.1%, verbal status for 74.0%, and adaptive functioning scores for only 55.9%. All the needed pieces were there for just 54.4% of children.⁵
• After statistically filling in missing data, 16.5% of the children with autism met that definition, while 32.1% met one part of it but not the whole thing.⁵
• Across all 8-year-olds, that worked out to 5.4 per 1,000 children for profound autism and 27.5 per 1,000 for non-profound autism in 2022 — the authors’ headline conclusion is that non-profound autism was the more common of the two.⁵
• The count moved a great deal depending on which definition was used: 33.5% higher with the earlier 2021 definition, 70.9% higher with a higher IQ cutoff, and 33.3% lower using only communication and adaptive scores.⁵

The label is also contested. The Autistic Self Advocacy Network, a national organization run by and for autistic people, opposes it, arguing it repeats the harm of older “functioning labels”: “Functioning labels don’t help autistic people get what we need. They hurt us.”⁶

Why it matters: Three things are worth holding onto. First, this is a research label, not a new diagnosis a clinician can give you and not a rule about who qualifies for services. Second, any number you read about how common “profound autism” is depends entirely on which definition was used — so look for that detail before comparing figures. Third, autistic people and families disagree about the term itself, and that disagreement is part of the story rather than a footnote to it. For more on how language choices land, see Autistic Person or Person With Autism? How We Talk About Autism.

One regional note, stated carefully. This report covers 13 sites and does not name the surveillance program it comes from.⁵ For comparison, CDC’s long-running autism tracking network — the ADDM Network — funds 16 sites for the 2022 and 2024 tracking years, including, for the first time, Puerto Rico.⁷ We cannot tell you whether this report’s 13 sites include Puerto Rico. What we can tell you is that one of its authors works at the Puerto Rico Department of Health.⁵ Two things follow: figures in this report will not match totals you may see from the full 16-site network, and Caribbean data is beginning to enter U.S. autism counts — slowly, and not yet in a form that supports any specific statement about the island.

What the evidence says helps autistic adults

Most autism research has focused on children. A meta-analysis in the Journal of Consulting and Clinical Psychology (2026) pulled together 35 studies with 1,631 participants to ask what supports actually help autistic adults. It included only randomized controlled trials and similar comparison-group studies, so single-person and before-and-after studies were left out.⁸

Pooling the results, the reviewers found small-to-moderate benefits in three areas, compared with usual care or a waiting list:⁸

• Mental health — Hedges’ g = 0.35 (95% CI 0.19 to 0.51)
• Social understanding — g = 0.45 (95% CI 0.17 to 0.74)
• Quality of life — g = 0.64 (95% CI 0.14 to 1.15)

Results for behavioral, cognitive, daily-living, and employment outcomes were not statistically significant.⁸ Two honest limits: the studies varied a lot in what they measured and how (for quality of life, most of the variation between studies was not explained by chance), and the wide confidence intervals mean the true size of each benefit is still uncertain.⁸

Why it matters: “Not statistically significant” is not the same as “does not work.” For employment especially, it mostly reflects how few good studies exist — which is a gap in the research, not a verdict on any one program. If you are considering a service for yourself or an adult you support, a fair question to ask is: what outcome does your program measure, and compared with what? Programs that can answer that are the ones generating the evidence the rest of us need. Our September roundup covered the other half of this picture: what autistic adults themselves say they need from mental-health care, and what the research says about depression in autistic adults. Those studies describe needs and patterns; this one asks whether the supports on offer measurably help.

A new program for families planning the move into adulthood

In our last roundup we covered research on what caregivers of autistic teens and young adults worry about most. A paper published online in the Journal of Pediatric Psychology on October 10, 2026 reports early results for a program built to address exactly that.⁹

Families FORWARD was developed in two phases. First, researchers interviewed 31 people — autistic young people, parents and caregivers, and professionals — about transition experiences and service gaps. Then 14 families tried the program, delivered remotely by community-based coaches, with a community advisory board of autistic young adults, parents, and professionals guiding the work.⁹

The program teaches four skills: family communication, collaborative goal-setting, problem solving, and systems navigation. In the pilot, every benchmark the researchers set in advance for feasibility, acceptability, and early promise was met, and families’ exit interviews pointed to better communication and more youth-centered planning.⁹

An honest limit: 14 families, with no comparison group. This is a pilot designed to show the program is workable and worth testing properly — not evidence that it works better than what families are doing already. It is also a research program, not a service you can sign up for today.⁹

Why it matters: You do not need to wait for a program to start on the four skills it teaches. Planning together with the young person rather than for them, writing down goals, and keeping your own record of who you spoke to and when are all things families can do now. Two of our guides may help: How to Get an IEP: A Step-by-Step Guide for Families and Caregiver Burnout: How to Spot It and What Helps. If asking for help is the hard part, see Boundaries and Support: How Caregivers Can Ask for Help.

Sources

1. Burstain TL, Jacques D, Burstain JM. “Association Between First MMR Vaccination Before Age 2 Years and Childhood Autism in a U.S. EHR Cohort of 2.5 Million Children.” Pediatric Infectious Disease Journal, published online July 28, 2026. doi:10.1097/INF.0000000000005349. PubMed 42520244.
2. Hviid A, Hansen JV, Frisch M, Melbye M. “Measles, Mumps, Rubella Vaccination and Autism: A Nationwide Cohort Study.” Annals of Internal Medicine 2019;170(8):513-520. doi:10.7326/M18-2101. PubMed 30831578.
3. Centers for Disease Control and Prevention. “Autism and Vaccines.” Vaccine safety, page date July 22, 2026. cdc.gov Autism and Vaccines.
4. Siegel M, Lord CL, Tager-Flusberg H, Ursitti J, Halladay A, Singer AT. “Developing a consensus research definition for profound autism using a modified Delphi method.” Molecular Autism 2026;17(1):28. doi:10.1186/s13229-026-00727-y. PMC13326320.
5. Shaw KA, Russell LA, DiRienzo M, et al. “Profound Autism Prevalence and Assessment Practices in a Population-Based Study.” Journal of the American Academy of Child and Adolescent Psychiatry, published online October 2, 2026. doi:10.1016/j.jaac.2026.09.019. PubMed 42826765.
6. Autistic Self Advocacy Network. “The ‘Profound Autism’ Label Hurts Autistic People” (toolkit). autisticadvocacy.org toolkit.
7. Centers for Disease Control and Prevention. “ADDM Network Sites.” Page date May 28, 2025. cdc.gov ADDM Network Sites.
8. Smith IC, Holmes LG, White SW. “Interventions for autistic adults: A meta-analysis.” Journal of Consulting and Clinical Psychology 2026;94(3):159-172. doi:10.1037/ccp0001003. PubMed 41926193.
9. Long KA, Suswaram S, Adebogun MB, et al. “Development and non-randomized pilot trial of Families FORWARD: a new program for families of autistic youth transitioning to adulthood.” Journal of Pediatric Psychology, published online October 10, 2026. doi:10.1093/jpepsy/jsag069. PubMed 42859903.