Morning Rounds: August 17-23

We saw significant movement this week in Alzheimer disease diagnostics, substance use epidemiology, and vaccine policy advocacy. News spans 2 new FDA-cleared blood tests, fresh data on infection-linked mood disorders and shifting substance use patterns, and a large coalition of medical groups pushing back on federal vaccine guidance.

Pharmaceutical Updates

FDA Clears Blood Test to Aid Evaluation for Alzheimer Disease

The US Food and Drug Administration (FDA) cleared PrecivityAD2 for marketing, a blood-based diagnostic test developed by C2N Diagnostics using technology invented at Washington University School of Medicine in St. Louis.¹ The test uses high-resolution mass spectrometry to measure amyloid beta 42 and 40 and 2 forms of tau protein—p-tau217 and total tau217—to detect amyloid pathology associated with Alzheimer disease. Previous validation studies found PrecivityAD2 diagnoses amyloid pathology with more than 90% accuracy, performing comparably to cerebrospinal fluid testing and brain imaging even in patients with mild cognitive symptoms. FDA clearance broadens marketing access beyond the existing physician-ordering pathway and may facilitate insurance coverage, improving affordability for patients undergoing Alzheimer disease evaluation. The test offers a less invasive option for evaluating patients presenting with early cognitive symptoms, potentially shortening the path to diagnosis and earlier treatment initiation.

Elecsys pTau217 Blood Test Cleared by FDA for Alzheimer Amyloid Assessment

The FDA cleared Roche's Elecsys Phospho-Tau (217P) Plasma test, a single-biomarker blood test developed to aid in identifying amyloid pathology in patients 55 years and older with signs or symptoms of cognitive decline.² The assay is the first and only FDA-cleared single-biomarker blood test that supports both rule-in and rule-out assessment of amyloid pathology using the same validated clinical cutoffs across primary and specialty care settings. Results are stratified into positive, intermediate, and negative categories and are intended to be interpreted alongside clinical history and other diagnostic findings rather than as a stand-alone test. The clearance adds a single-draw option for narrowing which patients with cognitive complaints warrant referral for confirmatory positron emission tomography imaging or cerebrospinal fluid testing.

Clinical Research

Community-Acquired Infections Linked to Higher Risk of Depression and Anxiety

A nationwide matched cohort study using Clalit Health Services registries in Israel found that community-acquired infections were associated with an increased risk of developing depression or anxiety, but not schizophrenia or bipolar disorder.³ Researchers followed 35,020 individuals with a history of cytomegalovirus, herpesviruses, hepatitis, influenza, or toxoplasma gondii infection, matched against an equal number of unexposed individuals, through 2024. Risk increased with infection burden, rising from a hazard ratio of 1.08 after 1 infection to 1.19 after 2 infections and 1.81 after 3 or more infections within the first 5 years post-infection. The associations were stronger in females, older individuals, and those from larger families. The findings suggest clinicians might consider infection history as a modifiable risk marker when assessing vulnerability to mood and anxiety disorders, particularly in young adult patients.

Cannabis Use Disorder Rises as Alcohol Use Disorder Falls Among US Adults

A cross-sectional study of 186,823 adults using National Survey on Drug Use and Health data from 2021 to 2024 found that cannabis use disorder (CUD) prevalence rose significantly among both men and women while alcohol use disorder (AUD) declined or held steady.⁴ Among men, past-year CUD increased from 7.3% to 9.3%, with moderate-to-severe CUD rising from 3.1% to 4.1%; among women, past-year CUD rose from 4.5% to 5.6%, with moderate-to-severe CUD increasing from 1.7% to 2.5%. Over the same period, the number of US adults with AUD fell from an estimated 28.8 million to 27.1 million. The trends were most pronounced among middle-aged and older adults, a pattern researchers linked to rising cannabis potency and broader legal access. The shift underscores a potential need for routine cannabis screening in clinical workflows similar to existing alcohol and tobacco assessment, particularly as patients increasingly perceive cannabis as a lower-risk substitute for alcohol.

Policy & Legislation

Medical and Health Groups Oppose Executive Order on Childhood Vaccines As Conversations Around Autism Continue

The American Psychiatric Association joined more than 210 medical, health, and patient advocacy organizations—including the American Academy of Pediatrics, American Medical Association, and American College of Obstetricians and Gynecologists—in a joint statement opposing a White House Executive Order that advises reducing and spacing out recommended childhood vaccines.⁵ The organizations stated the order lacks supporting evidence and undermines confidence in childhood vaccination as measles cases surge nationally and respiratory virus season approaches. The statement noted that although the order does not address autism, administration officials' remarks accompanying its release elevated debunked claims linking vaccines to autism, which the groups said diverts resources from legitimate autism research. The coalition urged parents and caregivers with vaccine questions to consult their child's clinician rather than the order's guidance.

References

1. FDA clears blood test to aid evaluation for Alzheimer's disease. Press release. August 21, 2026. Accessed August 24, 2026. https://medicine.washu.edu/news/fda-clears-blood-test-to-aid-evaluation-for-alzheimers-disease/

2. Roche receives FDA clearance for Elecsys pTau217, advancing Alzheimer's disease assessment across primary and specialty care. Press release. August 24, 2026. Accessed August 24, 2026. https://diagnostics.roche.com/us/en/news-listing/2026/fda-elecsys-ptau217-alzheimers-blood-test.html

3. Kramer A, Weinstein O, Givon-Lavi N, et al. Community-based infections and its association with mental disorder onset: a nationwide matched cohort study. Transl Psychiatry. 2026.

4. Han B, Compton WM, Hobin JA, et al. Trends in the prevalence and severity of alcohol and cannabis use disorders among US adults. JAMA Psychiatry. 2026.

5. More than 210 leading medical, health and patient advocacy groups oppose recent executive order on childhood vaccines. Press release. August 17, 2026. Accessed August 24, 2026. https://www.psychiatry.org/News-room/News-Releases/More-than-210-Leading-Medical-Health-and-Patient-A