People who have long COVID symptoms—those that linger well after the initial SARS-CoV-2 infection—can display signs of abnormal immune-cell activation in many of their organs and tissues, as well as leftover SARS-CoV-2 RNA in the gut, for more than 2 years after infection, according to a small study this week in Science Translational Medicine.

University of California, San Francisco researchers analyzed data on 24 people after their initial COVID-19 illness who underwent whole-body positron emission tomography (PET) imaging at time points ranging from 27 to 910 days (about 2 and a half years) after their acute COVID-19 cases. Eighteen of the patients had long COVID. 

The team used a tracer during PET imaging that selectively tags activated T cells and found that people with long COVID had certain tissues that were enriched for activated T cells in comparison with never-infected people who did not have long COVID (prepandemic controls). 

Furthermore, this T-cell activation correlated with symptoms of long COVID. For example, people who reported persistent lung problems had stronger signs of T-cell immune activation in their lungs.

Viral RNA in gut tissue

In addition, because the gut was one of the sites of activated T-cell enrichment, the scientists analyzed colorectal biopsies from five of the patients with long COVID. All five of these samples contained SARS-CoV-2 RNA.

The authors wrote, "In this first-in-human T cell activation PET imaging study of individuals after SARS-CoV-2 infection, we found evidence of persistent T cell activation in a variety of tissues. In some individuals, this activity may persist for years after initial COVID-19 onset and be associated with systemic changes in immune activation as well as the presence of [long COVID] symptoms."

"Overall, these observations challenge the paradigm that COVID-19 is a transient acute infection, building on recent observations in blood," the authors concluded.

The public health department for Seattle and King County this week said it is investigating a measles case involving an adult who had recently traveled internationally and warned of possible exposures at multiple area locations that the patient visited before the illness was confirmed.

In a statement, officials said the patient was at sites in Bellevue, Seattle, and Woodinville while infectious and that anyone who was at the locations when the person was there from June 27 to July 2 may have been exposed to the virus.

In Ohio, the Butler County General Health District yesterday announced the confirmation of a measles case in a child younger than 1 year old who is a resident of the county.

Officials said the child contracted measles during international travel, returning to the United States at a Chicago airport and returning to Ohio by car.

159 US cases so far this year

Nationally, 159 measles cases from 23 jurisdictions have been reported in the United States this year, well above the 58 cases reported in 2023, according to the latest update on June 27 from the Centers for Disease Control and Prevention.

The bulk of this year's cases were linked to spread involving a migrant shelter in Chicago, though sporadic cases continue to be reported. Earlier this year, health officials warned of a heightened risk of measles spread tied to a rise in global activity.