The UK Health Security Agency (HSA) recently posted an initial risk assessment of the BA.2.86 Omicron subvariant, which said the rapid appearance in multiple countries in people without travel histories suggests established international transmission.

The newly identified variant has many genetic mutations and is distant from BA.2, its likely ancestor, and currently circulating XBB variants. The similarity of the sequences so far—six samples from four countries—suggests relatively recent emergence and rapid growth, but the HSA said it has low confidence in that assessment, pending the examination of further sequences.

Though predictions of the combined effect of such a large number of mutations would be unreliable now, there is enough information to expect antigenic change. The HSA also said there are mutations in the spike protein that may be associated with changes in other viral properties.

Recent UK case

Identification of a recent UK case also suggests community transmission. The clinical site where the virus was found sequenced data rapidly, and surveillance data from the time that the specimen was collected may shed more light on UK transmission over 1 or 2 weeks.

Currently, it's not possible to gauge severity based on the sample from the UK patient, but the HSA said it would share data from surveillance systems, estimates of growth rates, and virus characterization when available.

COVID-19 infections among 2,400 vaccinated transplant recipients were common (19.7%) during SARS-CoV-2 Omicron variant predominance in the United States, but only 7.5% needed hospitalization, estimates a study published late last week in JAMA Network Open.

Researchers at New York University and Johns Hopkins University surveyed participants in a national cohort who reported receiving at least one COVID-19 vaccine dose from January 2021 through December 2022. The team sent follow-up surveys in January and June 2022.

Lung recipients hospitalized more often

Among 2,461 transplant recipients, 19.7% reported a COVID-19 infection, including 15 reinfections. The case incidence per 1 million person-days was 90 before the Delta variant era (January to May 2021), 304 during Delta (June to December 2021), 1,292 during Omicron BA.1 (January to March 2022), 1,051 during BA.2 (April to June 2022), and 1,066 amid BA.4, BA.5, and BQ.1 (July to December 2022).

COVID-19 incidence was lower among participants 60 years or older than among younger participants (420.2 vs 605.0, respectively) and similar if less than 2 years had elapsed since transplant (vs more than 2 years; 599.6 vs 485.7) and in lung versus nonlung recipients (572.8 vs 500.4). The incidence among transplant recipients followed a similar trajectory as among the general population, peaking during Omicron BA.1.

Among 464 infected participants, 7.5% were hospitalized. Hospitalized participants more often reported receiving stronger immunosuppressive regimens (56.8% vs 36.5%) and lung transplant (24.3% vs 9.5%). Hospitalization rates per 100 infections ranged from 14.1 pre-Delta to 2.3 amid BA.2.

The findings can guide counseling regarding the benefits of vaccination, and provide an evidence-based framing of risk and risk behaviors for populations most vulnerable to COVID.

The hospitalization rate was comparable among participants 60 years or older and younger participants (8.3 vs 7.4) but higher in lung than nonlung recipients (18.4 vs 6.6). Of 16 deaths, 5 were related to COVID-19.

The findings "can guide counseling regarding the benefits of vaccination, and provide an evidence-based framing of risk and risk behaviors for populations most vulnerable to COVID, such as transplant patients," senior author William Werbel, MD, PhD, said in a Johns Hopkins news release.

A systematic review and meta-analysis found that rapid point-of-care testing for respiratory pathogens does not reduce the antibiotic prescribing rate, Finnish researchers reported late last week in Open Forum Infectious Diseases.

Out of 754 abstracts screened, the researchers analyzed 10 randomized controlled studies involving 7,323 patients that compared the impact of rapid point-of-care viral and/or bacterial polymerase chain reaction (PCR) tests on antibiotic prescribing for acute respiratory infections regardless of the blinding and comparator. Four of the studies analyzed influenza and respiratory syncytial virus (RSV) tests, and six analyzed multiplex (viral and/or bacterial) tests. The primary outcome was the antibiotic prescribing rate.

Overall, the antibiotic prescribing rate was 52.7% in the testing group and 54.6% in the control group (risk ratio [RR], 0.99; 95% confidence interval [CI], 0.96 to 1.01), with evidence quality ranked as moderate. When the researchers analyzed the influenza + RSV testing group, the prescribing rate was 48.2%, compared with 48.7% in the control group (RR, 0.97; 95% CI, 0.92 to 1.02). The prescribing rate in the multiplex testing group compared with the control group was 54.3% versus 57.3% (RR, 1.00; 95% CI, 0.96 to 1.04).

In an age-stratified analysis of the three studies that included children and five adults-only studies, the antibiotic prescribing rates showed no evidence of a difference (children RR, 1.03; 95% CI 0.81 to 1.30; adults RR, 0.98; 95% CI, 0.96 to 1.01). Analysis of five studies that compared antibiotic duration found no evidence that duration was shorter in the testing group.

Non-medical factors may play a role

The study authors say the findings are consistent with previous studies and suggest that non-medical factors, such as patient preference and physician attitude, may also play a role in antibiotic prescribing for respiratory illnesses.

"Further strategies and studies are needed to provide evidence-based interventions for antibiotic prescription reduction," they wrote.

The Centers for Disease Control and Prevention (CDC) has announced a Salmonella outbreak linked to small pet turtles that has so far sickened at least 26 people in 11 states, with 9 people hospitalized, but no deaths reported.

Illness onsets began in October 2022, and two outbreak strains are involved. Salmonella Stanley was identified in 24 infections, and Salmonella Pomona was detected in 2 patients. Most people recover without medical care, so the true number of sick people is likely much higher than reported cases. The latest illness onset is July 19, and roughly one third of the patients are younger than 5 years old.

PulseNet, the CDC's genetic subtyping network, has identified illnesses that may be part of the outbreak, and whole-genome sequencing suggests that the bacteria from sick people are genetically related.

80% reported contact with turtles

State and local health officials interviewed people about their contacts with animal in the week before symptoms began, which revealed that of 20 people with available information, 16 (80%) had contact with pet turtles, mostly small ones with shells smaller than 4 inches long. Of 13 patients with purchase information, 6 got them from online retailers, 5 from stores, and 1 from a reptile show.

In July, the Tennessee Department of Health obtained samples from two turtles—bought from a pet store—and their tank in a sick patient's home, and the samples closely matched samples from other sick people.

Small turtles have been linked to several Salmonella outbreaks in the past, including one in 2022 that was linked to at least 28 infections in 16 states. Federal law bans the sale of small turtles, but they can sometimes be found online or through other outlets. The CDC has warned people to avoid having small turtles for pets.