CDC announces 10-state Listeria outbreak of unknown origin

News brief

The Centers for Disease Control and Prevention (CDC) said this week that at least 11 people have been sickened and 10 hospitalized in a multistate outbreak linked to Listeria going back several years, but officials have not yet zeroed in a specific food culprit.

Outbreak patients tend to be older, but no deaths have been recorded. Sick people range in age from 47 to 88 years, with a median age of 73, and 8 of the 11 are women. Samples from case-patients were collected from July 3, 2018, to January 31, 2023.

Michigan reported two cases, while the other affected states had one each. They are Arkansas, California, Colorado, Missouri, New York, North Carolina, Pennsylvania, South Dakota, and Washington.

Listeriosis can cause a variety of symptoms, such as fever and diarrhea, similar to other foodborne pathogens. Symptoms usually start within 2 weeks after eating food contaminated with Listeria but may start as early as the same day or as late as 10 weeks after. It can be especially serious and even deadly in pregnant women, seniors, and those with weakened immune systems.

"Public health officials are interviewing people in this outbreak to find out what foods they ate before getting sick," the CDC said. "Investigators are collecting as much information as they can to solve this outbreak."

Black, Hispanic people may be more likely to have long COVID but not be diagnosed

News brief

Woman with headacheBlack and Hispanic COVID-19 survivors are more likely to have persistent symptoms and health problems than their White peers but are less likely to receive a diagnosis, and the single available medical code for long COVID may not capture the wide variation in symptoms and severity, suggest two new studies from the National Health Institute's (NIH's) Researching COVID to Enhance Recovery (RECOVER) Initiative.

In one study, published in the Journal of General Internal Medicine, a team led by Weill Cornell Medicine researchers analyzed the health records of 62,339 adults who tested positive for COVID-19 in New York City from March 2020 to October 2021. The researchers monitored participants' health for 1 to 6 months and compared their outcomes to those of COVID-naïve adults.

One in four of the 13,106 hospitalized COVID-19 patients were Black or Hispanic, compared with 1 in 7 White patients. Non-White patients had very different long-COVID conditions and symptoms than their White counterparts.

Identifying potential racial and ethnic disparities in long COVID is an important step toward making sure we have an equitable response.

"Identifying potential racial and ethnic disparities in long COVID is an important step toward making sure we have an equitable response to the long-term consequences of coronavirus infection," lead author Dhruv Khullar, MD, MPP, said in a Cornell news release.

Long COVID may have many subtypes

The second study, led by University of North Carolina researchers, was published in BMC Medicine. The team analyzed the health records of 33,782 COVID patients of all ages at 34 US medical centers from October 2021 to May 2022.

The patients tended to be White, female, and non-Hispanic and lived in low-poverty communities and had greater healthcare access. The pattern suggests that not all long-COVID patients are being diagnosed, the authors said.

The symptoms could also be grouped into clusters of conditions and by age, suggesting that the only available medical code, "U09.9, post COVID-19 condition, unspecified," is insufficient. "It is likely that subtypes of long COVID exist, and such subtypes may correlate with specific underlying mechanisms that should be targeted by different interventions," they wrote.

It is likely that subtypes of long COVID exist.

Original mRNA COVID vaccines protect young kids against Omicron, but efficacy wanes

News brief

Omicron infection for US children 3 to 5 years old, but it is considerably higher 1 to 2 months after vaccination compared with 3 to 4 months, according to a study today in Morbidity and Mortality Weekly Report.

The Centers for Disease Control and Prevention's (CDC's) Advisory Committee on Immunization Practices recommended on June 18, 2022, that children 6 months to 5 years old receive either two doses of the Moderna or three doses of the Pfizer-BioNTech vaccine as a complete series. Both were monovalent (single-strain) vaccines, as the new bivalent (two-strain) booster that contains an Omicron variant component was not yet available.

For the study, CDC researchers assessed vaccine efficacy from July 2022 through February 2023, when the Omicron variant was predominant. The Moderna group comprised kids 3 to 5 years old, while Pfizer recipients were 3 to 4 years old.

From 60% protection early on to 36%

The Moderna group received a nucleic acid amplification test (NAAT) from August 1, 2022, through February 5, 2023. In that group, vaccine effectiveness (VE) against symptomatic Omicron infection was 60% (95% confidence interval [CI], 49% to 68%) 2 weeks to 2 months after the second dose and 36% (95% CI, 15% to 52%) 3 to 4 months after the second dose.

Children receiving the Pfizer vaccine were tested with a NAAT from September 9, 2022, to February 5, 2023. VE of three doses against symptomatic Omicron was 31% (95% CI, 7% to 49%) from 2 weeks to 4 months after receipt of the third dose. Both groups also included unvaccinated same-aged children.

Those who are eligible should receive a bivalent vaccine dose.

The authors conclude, "Children should stay up to date with COVID-19 vaccines, including completing the primary series; those who are eligible should receive a bivalent vaccine dose." The CDC expanded its recommendations for the use of bivalent vaccines to children aged 6 months or older on December 9, 2022.

US flu activity declines further; flu subtypes show some shifts

News brief

The nation's flu indicators showed more signs of decline, including fewer hospitalizations and deaths, but the percentage of 2009 H1N1 and influenza B viruses are showing small rises in a season that started early and was dominated by the H3N2 strain, the Centers for Disease Control and Prevention (CDC) said today in its weekly update.

The percentage of outpatient visits for flulike illness remained just above the national baseline of 2.5%, though 7 of 10 regions are below their baselines. Only three jurisdictions are reporting high flu activity: New York City, the District of Columbia, and New Mexico.

At public health labs, 89.6% of samples that were positive for flu were influenza A, and 10.4% were influenza B, up from 5.2% the week before. Proportions of influenza B viruses typically rise in the latter months of the flu season. Of subtyped influenza A viruses, 2009 H1N1 has nosed ahead of H3N2, making up 56% of samples.

Five more pediatric flu deaths were reported, raising the season's total to 111 for the season. All were due to influenza A, and the one subtyped virus was H3N2.

Shigellosis outbreak reported in travelers returning from Cabo Verde

News brief

ShigellaThe European Centre for Disease Prevention and Control (ECDC) said today that more than 250 shigellosis cases among travelers returning from Cabo Verde have been reported in an outbreak that began in November 2022.

In a rapid risk assessment, the ECDC said there have been 221 confirmed Shigella sonnei infections and 37 possible cases from the European Union/European Economic Area (EU/EEA), United Kingdom, and United States with links to Cabo Verde, an archipelago and island country off the western coast of Africa. Many of the case-patients are reported to have stayed in all-inclusive hotels located in the region of Santa Maria on the island of Sal. The most recent cases were reported in Sweden on Jan 19.

Shigellosis is a gastrointestinal condition caused by one of the four species of Shigella bacteria: Shigella sonnei, S flexneri, S boydii, or S dysenteriae. Symptoms range from mild diarrhea to severe dysentery. Shigella infection is commonly associated with exposure to food or water that has been contaminated by human feces, but transmission can also occur through direct person-to-person contact.

The ECDC says the most likely source of the outbreak is food, though it has not ruled out person-to-person transmission. Sequencing of 106 isolates shows a genetically compact cluster, which indicates a common source of infection. Co-infections with other gastrointestinal pathogens, including Salmonella and Escherichia coli, have also been reported.

The S sonnei strains identified among case-patients have predicted resistance to trimethoprim and streptomycin, with some isolates exhibiting multidrug resistance.

The ECDC says it is in regular contact with officials in Cabo Verde to support investigations into the source of the outbreak and is encouraging public health authorities in the EU/EEA to increase awareness among health professionals on Shigella infections among people who recently traveled to the islands.

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