Sweden probes severe influenza B cases in kids

News brief

Swedish health officials are investigating a cluster of severe influenza B infections in children and adolescents, some of whom had complications, including myocarditis and meningoencephalitis, the European Centre for Disease Prevention and Control (ECDC) said in its most recent weekly communicable disease update.

The cases have been reported in previously healthy kids, and some children have required intensive care unit (ICU) admission. Health officials are assessing if the pattern exceeds expected levels.

Sweden's Public Health Agency, in its latest weekly flu update, said the cases occurred in Orebro County, located in the central part of the country about 130 miles west of Stockholm.

Cases rising for a month

Influenza B activity typically picks up later in the flu season, and the ECDC said flu B viruses have been on the rise in Sweden since about the middle of February. Two suspected cases and one confirmed case have epidemiologic links. Sequencing suggests that the Victoria lineage virus is similar to those circulating in other parts of the world. It's not known how many kids were vaccinated against flu or had COVID-19 before they got sick with flu B.

The ECDC said reduced flu circulation and exposure to the virus in the past few seasons may have lowered population immunity. "So it is important to remain vigilant for signals of increased severity in different population groups," it said.

It is important to remain vigilant for signals of increased severity.

Influenza B infections are known to be more common in children and can cause complications, resulting in hospitalization or death. In 2019, an early-season spike in influenza B activity in Louisiana resulted in a number of hospitalizations, one of them fatal.

5,000 US COVID deaths may have been averted in winter 2022 under higher Paxlovid use

News brief

Mary Van Beusekom, MS

COVID patient in hospital — US Navy / Flickr cc

About 4,800 US lives could have been saved during the winter 2021-22 SARS-CoV-2 Omicron wave if 5% of COVID-19 patients had taken the antiviral drug Paxlovid, estimates a modeling study published late last week in JAMA Health Forum.

Brown University and Stanford University researchers modeled declines in hospitalizations and deaths under 5% Paxlovid uptake (the current rate) from December 2021 to March 2022. Paxlovid was authorized for use in high-risk adults and children 12 years and older in December 2021.

The team conducted sensitivity analyses by building models to estimate decreases in hospital admissions and deaths (models 2 and 3), subpopulation analyses (models 4 to 6), projections if even more patients had taken Paxlovid (models 7 and 8), and required tests and Paxlovid courses to avert severe outcomes (models 9 and 10).

Just 5% uptake may have cut deaths by 3%

Assuming 78% of infections requiring hospitalization were detected within 5 days, 5% Paxlovid uptake, effectiveness of 67% against hospitalization and 81% against death, 2.7% fewer hospitalizations and 3.2% fewer deaths may have occurred.

In sensitivity analyses, estimated COVID-19 hospitalizations declined 0.5% to 7.5%, and deaths fell 0.6% to 7.5%. In nursing homes, higher Paxlovid uptake may have lowered hospitalizations and deaths 7.7% and 9.3%, respectively (model 4).

If Paxlovid uptake were 40% (model 7), hospitalizations and deaths may have fallen 21% and 25%, respectively. If uptake were 80% (model 8), hospitalizations and deaths may have declined 42% and 51%, respectively.

If Paxlovid uptake were 40%, hospitalizations and deaths may have fallen 21% and 25%, respectively.

At 5% Paxlovid uptake (model 1), 4.8 million symptomatic tests and 2.5 million Paxlovid courses would have been needed to avert 2.7% of hospitalizations and 3.2% of deaths. At 80% uptake (model 8), 75.3 million tests and 39.8 million Paxlovid courses would have been needed to avert 41.8% of hospitalizations and 50.5% of deaths.

"We estimated that had current Paxlovid uptake been achieved in January 2022, 4.8 thousand deaths would have been averted," the authors wrote. "We provide a simple, flexible framework for understanding the resource requirements and benefits associated with future expansions of the test-to-treat initiative."

Study: Sharing of multidrug-resistant bacteria between people, pets rare

News brief

Chris Dall, MA

A study to be presented at next month's European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) suggests the sharing of multidrug-resistant organisms (MDROs) between pets and their owners can occur but is rare.

In a case-control study conducted at Charite University Hospital Berlin in Germany, researchers collected and analyzed nasal and rectal swabs from 2,891 hospital patients, including 1,184 patients with previous MDRO colonization and 1,707 newly admitted control patients.

Dog and cat playing — Eran Finkle / Flickr cc

Patients with pets were asked to collect nasal and rectal samples from their cats and dogs for analysis. The researchers also queried the patients about the number of household pets they owned, closeness of contact, pet medical history, and other potential risk factors for MDRO carriage, such as recent hospital stays or antibiotic use. Phenotypically matched MDROs were tested for genetic relatedness using whole-genome sequencing (WGS).

Of the patients, 30% tested positive for MDROs, and 70% tested negative. The rate of dog and cat ownership was 11% and 9% in MDRO-positive patients, respectively, and 13% and 13% in MDRO-negative patients. Of the 400 pets tested for MDRO carriage, 14.8% of dogs and 4.6% of cats were colonized.

Among 400 tested pairs of pets and owners, researchers identified four pairs of phenotypically matching MDROs and one pair of third-generation cephalosporin-resistant Enterobacterales that was genotypically identical based on WGS. Analysis of one pair of vancomycin-resistant Enterococci is still pending.

Carriers can shed bacteria into their environment for months.

"Our findings verify that the sharing of multidrug-resistant organisms between companion animals and their owners is possible," study author Carolin Hackmann, MD, said in an ECCMID press release. "Although the level of sharing between hospital patients and their pets in our study is very low, carriers can shed bacteria into their environment for months, and they can be a source of infection for other more vulnerable people in hospital such as those with a weak immune system and the very young or old."