SARS-CoV-2 RNA can persist in blood, tissue, may play role in long COVID, research suggests

News brief

SARS-CoV-2 viral fragments can remain in blood and tissue for more than a year after infection, which researchers at the University of California San Francisco (UCSF) say could contribute to long COVID.

In two studies, the researchers found SARS-CoV-2 RNA in the blood for up to 14 months post-infection and for more than 2 years in connective-tissue samples from 171 COVID-19 survivors without evidence of reinfection. The team obtained the samples from UCSF's Long COVID Tissue Bank, which houses samples donated by patients with and without long COVID.

The investigators presented the results at this week's Conference on Retroviruses and Opportunistic Infections in Denver.

Double the risk in severely ill patients

The probability of having persistent viral fragments was about double in hospitalized participants and in those who reported being very ill but weren't hospitalized. "As a clinician, these associations convince me that we are on to something, because it makes sense that someone who had been sicker with COVID would have more antigen that can stick around," Michael Peluso, MD, who led the studies, said in a UCSF news release.

These two studies provide some of the strongest evidence so far that COVID antigens can persist in some people, even though we think they have normal immune responses.

Because viral RNA was found in connective tissue where immune cells are located, the study authors said the RNA may have been causing an immune response. "These two studies provide some of the strongest evidence so far that COVID antigens can persist in some people, even though we think they have normal immune responses," Peluso said.

He added that more research is needed to determine whether the viral RNA contributes to long COVID and related events such as heart attack and stroke. His team is involved in clinical trials that are studying whether monoclonal antibodies or antiviral drugs can eliminate the RNA and benefit long-COVID patients. "There is a lot more work to be done, but I feel like we are making progress in really understanding the long-term consequences of this infection," Peluso said.

Chicago reports 2 measles cases

News brief

Lisa Schnirring

The Chicago Department of Public Health (CDPH) has reported two measles cases, one at a center for new migrants and another in a person who had interactions with domestic and international travelers, on a day that US officials raised the national tally to 45.

In an announcement today, the CDPH said the migrant center case involves a young child at a shelter in Pilsen. The child has recovered and is no longer infectious. Officials are asking all shelter residents to remain in place until they can determine if residents are vaccinated against measles. Unvaccinated people will be screened for symptoms and offered the measles, mumps, and rubella (MMR) vaccine.

Yesterday the CDPH announced another case, the city's first since 2019. So far, the source of the patient's infection isn't known. The patient had not traveled but had interactions with domestic and international travelers. No links have been found between the patient and a recent Indiana case who had visited Chicago in February.

The patient's infectious period ended on March 6, and he or she is recovering at home. The CDPH is tracking potential exposures at Swedish Hospital in Chicago and on a bus route.

CDC reports 4 more measles cases

In a weekly update today, the Centers for Disease Control and Prevention (CDC) reported 4 more measles cases, raising the national total this year to 45. It added 1 more affected jurisdiction, Illinois, which raises the number of affected locations to 17.

In January, the CDC urged clinicians to be alert for measles cases, given a steady rise in global cases amid drops in vaccine coverage.

In its background information, the CDC said measles outbreaks are occurring in every region of the world. The agency warned that outbreaks can happen in areas where people are unvaccinated or undervaccinated, including the United States.

Five African countries report more vaccine-derived polio cases

News brief

Lisa Schnirring

Five African countries reported more polio cases this week, all involving circulating vaccine-derived poliovirus type 2, according to the latest update from the Global Polio Eradication Initiative.

polio vax supplies — UN Photo/JC McIlwaine/Flickr cc

In West Africa, Guinea confirmed 1 case, which was reported from Kindia and is included in its total for 2023, which is now at 47. Mali reported 3 cases in Bamako, Menaka, and Kayes, lifting its 2023 total to 15. Nigeria reported 8 cases, including 3 to add to its 2023 total. Four cases were in Kano, with the others in Sokoto, Katsina, and Kebbi.

In Central Africa, Chad reported 1 case in Moyen Chari, which is counted with its 2023 total, which has now reached 55.

Meanwhile, in East Africa, Somalia reported three cases, which bring its 2023 total to eight. The latest patients are from Bay and Galgadud.

Indonesia donates polio vaccine to Afghanistan

In related news, Indonesia's international development agency has donated 10 million doses of polio vaccine to Afghanistan, one of the few countries where wild poliovirus type 1 is still detected.

The doses were made by Bio Farma, based in Indonesia, and the amount is enough to vaccinate 3.3 million children younger than 3 years old, according to Bernama, Malaysia's government news agency. UNICEF will partner with Afghani officials to help transport and distribute the vaccine.