News Scan for May 17, 2021

News brief

CDC wraps up latest queso fresco Listeria outbreak investigation

An investigation into a Listeria moncytogenes outbreak linked to a New Jersey company's queso fresco cheese has ended, with 14 cases reported in four states, the US Centers for Disease Control and Prevention (CDC) said May 14 in a final update.

The final total reflects the addition of two more cases since the CDC's last update on Mar 1. The most recent illness onset was Mar 17. Twelve people were hospitalized, and one person died. Most of the patients were Hispanic, and half were female. Four were sick during their pregnancies; two lost their babies, one baby was born early, and one woman is still pregnant after recovering from her infection.

Of 11 people interviewed, 8 had eaten queso fresco, including 4 who named brands made by El Abuelito, based in New Jersey. Tests on cheese samples from a store in Connecticut identified a strain that closely resembles the one that made people sick. The company recalled all queso fresco products on Feb 17, then a week later recalled all products made or packaged at the same facility.

The CDC urged people—especially those at high risk for complications, such as pregnant women—to avoid eating soft cheeses like queso fresco unless they are labeled as made with pasteurized milk. It warned, however, that even Hispanic fresh and soft cheeses made with pasteurized milk can become contaminated with Listeria if they are produced in unsanitary conditions.
May 14 CDC food safety alert

 

Irrigation water spotlighted as likely red onion Salmonella outbreak source

A Food and Drug Administration (FDA) investigation into a large Salmonella Newport outbreak linked to red onions from California's Southern San Joaquin and Imperial Valley growing regions found several contributing factors, with the main hypothesis that contaminated irrigation water may have been the source.

The outbreak was unusual, because it was the nation's largest in more than a decade, with hundreds of related cases reported in Canada, and it involved red onions, which hadn't been linked to earlier foodborne illness outbreaks. The event that unfolded in 2020 sickened 1,127 people in the United States and 515 in Canada.

In an investigation report posted on May 13, the FDA said genetic evidence of the outbreak strain wasn't found in extensive sampling, but evidence of Salmonella Newport was found in a small number of sediment and water samples from one of the growing fields, leading to the main hypothesis that contaminated irrigation water may have been the source.

Visual observations found other possibilities, including sheep grazing on adjacent land, signs of animal intrusion, and packing house factors.

The FDA said genetic findings in some of the sediment and water showed links to earlier Salmonella Muenchen and Montevideo outbreaks linked to sprouts, hinting at pathogen persistence in the growing region that could pose a risk to a range of produce.
May 13 FDA investigation report

COVID-19 Scan for May 17, 2021

News brief

Comorbidities, racial disparity found in homeless hospital COVID patients

Almost two thirds of homeless patients hospitalized for COVID-19 were of non-White descent and more than 80% had at least one comorbidity, according to a descriptive study in The Journal of Infectious Diseases yesterday.

The researchers analyzed 199 COVID-hospitalized adults who were experiencing homelessness out of the 2,872 (30.2%) patients in the COVID-NET database with homelessness status from Mar 1 to May 31, 2020. The cohort was 82.9% men, had a median age of 53 years, and were mostly non-White (63.3%).

When analyzing the patient data, the researchers used weighted percentages (WPs) to reflect what the population estimates would be if every medical record they pulled had homelessness information. For instance, in the cohort, almost 1 in 5 patients had a mental illness (38, 19.1%), but weighting changed the proportion to 1 in 12 (8.4%).

Most patients had at least one underlying health condition (155; WP, 83.0%), with the most common being high blood pressure (77; WP, 43.9%), cardiovascular disease (36; WP, 24.9%), obesity (59; WP, 23.6%), and chronic lung disease (43; WP, 22.3%). Most were also current smokers (105; WP, 45.9%), and 70 (WP, 33.7%) abused alcohol.

The median length of hospital stay was 4 days, and 37 were admitted to the intensive care unit (ICU; WP, 16.9%). Eighteen people needed invasive mechanical ventilation (WP, 11.3%), while 27 (WP, 15.0%) needed any type of respiratory support. Six patients died (WP, 1.1%).

Compared with a COVID-NET study of the general adult population in Clinical Infectious Diseases in July 2020, this study similarly shows a high prevalence of comorbidities. The current study group, however, had a younger median age (53 vs 62 years) and a higher proportion of minorities and current smokers.

Additionally, the 2020 study revealed that mechanical ventilation procedures did not vary by race and ethnicity and that White patients had a higher prevalence of in-hospital death. This study's results indicated that Hispanic and Black people accounted for most instances of mechanical ventilation or in-hospital death.
May 16 J Infect Dis study

 

COVID-19 reinfection found in 2% of university students

In the spring 2021 semester, 2.2% of Clemson University, South Carolina, students previously infected with COVID-19 were diagnosed as having been reinfected, according to a study published yesterday in Clinical Infectious Diseases.

The researchers looked at 16,101 students 17 to 24 years old from Aug 19 to Oct 5, 2020, as those after may have lingering viral RNA during weekly spring semester testing. Going into the spring semester, 12.6% of the cohort were considered to have a previous COVID-19 infection.

The university conducted mandatory weekly saliva tests during the spring 2021 semester, with a compliance rate of 83%. Overall, 44 students were reinfected (2.2% of the previously infected cohort), compared with 12.1% of students who had their first COVID-19 infection during the spring 2021 semester. The researchers estimate that protection from reinfection was 84% (95% confidence interval, 78% to 88%).

The reinfected students had a median age of 20.3 years. Most were female (51.4%) and didn't live in the dorms (66.2%) The median time to reinfection was 129 days, and the researchers say the Kaplan-Meier probability estimate of no reinfection for at least 8 months is 97.2%.

"Since 16% of this population remains susceptible to reinfection, precautions should still be employed by previously infected individuals (e.g., face coverings)," the researchers write. (The article was received by the journal Apr 17, 2021, before the CDC's revised mask guidelines May 13.) "As natural protection is not guaranteed, these findings strongly support vaccination of those previously infected with SARS-CoV-2. However, individuals without previous SARS-CoV-2 infections could be given prioritization when vaccines are in short supply."
May 16 Clin Infect Dis study

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