China has reported two more human H9N2 avian flu cases, which involve children in two different provinces, Hong Kong’s Centre for Health Protection (CHP) said today in its weekly avian flu update.

Both patients are 1-year-old girls. The first, from Guizhou province in southern China, became ill on October 28. The other, from neighboring Guangxi province, became ill on November 18.

The report did not note the patients' conditions or exposure to the virus.

H9N2 is known to circulate in poultry in the region, where sporadic infections are reported, especially in children, who typically experience mild disease following exposure to poultry. The new cases raise China’s H9N2 total for the year to 15 cases.

A paper published yesterday in the American Journal of Infection Control describes a small cluster of extensively drug-resistant (XDR) Shigella cases in California.

The three cases of XDR Shigella sonnei were identified in men who have sex with men (MSM) in Los Angeles who all presented with symptoms within 3 months of one another in 2023. All three men had reported histories of high-risk sexual behavior, and one was HIV-positive. Stool tests confirmed S sonnei infection, and antimicrobial susceptibility testing results showed resistance to azithromycin, ciprofloxacin, ceftriaxone, trimethoprim-sulfamethoxazole, and ampicillin, meeting the Centers for Disease Control and Prevention definition of XDR.

Because the temporal proximity of the cases prompted concerns for a potential outbreak, whole-genome sequencing of S sonnei isolates from the patients was performed. The results showed all three cases were highly genetically related, carried similar antimicrobial resistance genes (including bla_CTX-M-15), and belonged to an S sonnei lineage that's distinct from other globally circulating strains.

"The discovery of a novel XDR S. sonnei actively spreading in Los Angeles is alarming," researchers from the David Geffen School of Medicine at the University of California, Los Angeles, wrote. "While most people recover from Shigella infections without antibiotics, patients who require treatment and who fail to respond to usual antibiotics such as ciprofloxacin and azithromycin may need alternate treatment regimens."

Growing number of outbreaks

Shigellosis is a highly infectious gastrointestinal condition caused by one of the four species of Shigella bacteria: S sonnei, S flexneri, S boydii, or S dysenteriae. It's transmitted by the oral-fecal route; via contaminated fomites, food, and water; or by direct person-to-person contact. 

Though small, the outbreak is one of a growing number of XDR Shigella outbreaks that have occurred in recent years in Europe, the United Kingdom, Canada, and the United States. These outbreaks have primarily occurred among MSM and homeless populations.

The authors say their study provides "timely and deeper insights" into the spread of XDR Shigella in the United States.

Socially vulnerable adults hospitalized for influenza required invasive mechanical ventilation and/or extracorporeal membrane oxygenation (ECMO) support at greater rates than their higher-income counterparts during five respiratory virus seasons in the United States, concludes a study published in JAMA Network Open.

The Centers for Disease Control and Prevention (CDC)-led study used data from the US Census and the CDC's Influenza Hospitalization Surveillance Network of counties in 13 states to assess death rates and the use of respiratory interventions, flu vaccinations, and antiviral prescriptions among 57,964 hospitalized flu patients from 2014 to 2019.

"Influenza may disproportionately impact socially vulnerable populations, ie, people with community factors that limit disease prevention and management, such as poverty, discrimination, reduced transportation, and dense housing," the researchers noted. "Social determinants can contribute to preventable differences in disease burden and health opportunities."

Less access to vaccines, antivirals

Social vulnerability was greater for patients who were from the Western Census region (relative change from lowest to highest vulnerability, 12.0%), women (6.3%), Hispanic (339.3%), Black (504.9%), or American Indian/Alaska Native (166.7%).

Influenza may disproportionately impact socially vulnerable populations, ie, people with community factors that limit disease prevention and management, such as poverty, discrimination, reduced transportation, and dense housing.

People living in socially vulnerable areas had higher rates of invasive mechanical ventilation and/or ECMO (adjusted prevalence ratio [aPR], 1.25), primarily due to socioeconomic status (aPR, 1.31) and household composition and disability (aPR, 1.20). Receipt of these interventions was partially mediated by vaccination status, the presence of chronic conditions, and respiratory symptoms.

Among patients of all ages, the proportion of deaths dropped 16.7% as social vulnerability increased, except for those aged 18 to 49 years, in whom deaths climbed 134.3% as social vulnerability increased.

The percentage of patients receiving flu vaccines fell 19.4% with increasing social vulnerability, and the percentage vaccinated by October 31 declined 6.8%. Early in-hospital antiviral initiation and prehospital antiviral receipt decreased 1.0% and 17.3%, respectively, along with greater vulnerability.

The results support that low socioeconomic status is linked to reduced access to flu vaccines and prehospitalization antivirals and higher proportions of asthma, chronic lung disease, and more respiratory signs and symptoms, the authors said.

• A new risk evaluation for the XEC SARS-CoV-2 variant from the World Health Organization (WHO) and its Technical Advisory Group on Virus Evolution says the additional public health risk is low. XEC is a recombinant of two JN.1 lineages, KS.1.1 and KP.3.3, that was first detected in late June and designated as a variant under monitoring (VUM) on September 24. Currently, it is the only virus on the WHO’s VUM list that is increasing in prevalence globally. The group said due to limited escape from JN.1 or KP.2 booster vaccines, continued spread from the XEC variant alone is unlikely to increase the burden on national public health systems compared to other Omicron sublineages.
• At a briefing today on three main emerging health threats in the WHO Americas region, the head of the Pan American Health Organization (PAHO) raised concerns about rising dengue virus, Oropouche virus, and H5N1 avian flu cases but said there are effective strategies for battling the outbreaks. Jarbas Barbosa, MD, PAHO’s director, said the region this year has experienced record dengue activity since record-keeping began in 1980, with 12.6 million cases reported so far, nearly three times the number reported in 2023. The region has seen about 21,000 severe cases and more than 7,700 deaths, with Argentina, Brazil, Colombia, and Mexico reporting most of the cases. He also noted the officials have noted a greater impact on children, with 70% of deaths reported in that age-group in countries such as Guatemala.
• Finland’s Institute for Health and Welfare (THL) has identified type 2 vaccine-derived poliovirus type 2 (VDPV2) in wastewater samples from Tampere, the Helsinki Times reported yesterday. Leif Lakoma, MD, MPH, the THL’s chief physician, told the Times that the country reported a similar finding 10 years ago and that the detection is rare but not unexpected. Finland is the fourth European country to report the detection of the virus in wastewater over the past few months. Others include Spain, Poland, and Germany.