Seasonal influenza vaccination reduced the risk of related emergency department (ED) visits and hospitalizations among US children both with and without underlying medical conditions, though protection was somewhat lower in children with chronic conditions, suggests an analysis published in Pediatrics.

Led by researchers at Vanderbilt University Medical Center, the team analyzed data from 15,875 children aged 6 months to 17 years who presented to EDs or were admitted to hospitals across the United States during five flu seasons (2015 to 2020). Influenza was confirmed using molecular testing, and vaccination status was verified through immunization registries or health records.

Among the children included in the analysis, 2,821 (18%) tested positive for flu, and 40% of those with confirmed cases had at least one underlying medical condition, most commonly respiratory conditions such as asthma.

Vaccine effectiveness (VE) against flu-related ED visits or hospitalizations was 43% among children with underlying conditions, compared with 53% among children without underlying conditions. 

Effectiveness varies by condition type

VE varied by type of condition. Protection was lowest among children with respiratory conditions, at 31%. Higher VE estimates were observed among children with endocrine conditions (64%) and neurologic or neuromuscular conditions (53%). For children with oncologic and/or immunosuppressive conditions, VE was 48%. But “all demonstrated significant protection,” write the authors, “suggesting that influenza vaccination remains broadly effective for all children.”

The team noted that, during the study, vaccine uptake appeared low in both kids with and without underlying conditions and that coverage is likely even lower now with the increase in vaccine hesitancy since the COVID-19 pandemic began. 

“Given the increased risk for severe influenza complications in children with underlying conditions, it is crucial to identify strategies to improve vaccination uptake and investigate new approaches to vaccination in these populations,” write the authors. 

Real-world data from Japan suggest that an organic mental disorder (one not caused by psychiatric illness, such as Alzheimer’s disease [AD] and/or delirium) is a key risk factor for COVID-19 infection and hospitalization among older adults.

Researchers at Juntendo University in Tokyo analyzed data on patients registered in the Japanese Health Insurance Database between January 2014 and December 2019 to identify hospitalized patients aged 60 years and older newly diagnosed as having COVID-19 by December 2020. Follow-up ended in October 2022. 

The 8,072 patients were matched 1:1 with uninfected peers by age, sex, and illness onset. The researchers conducted a case-control study to identify risk factors for COVID-19 infection in the three months before diagnosis and a retrospective cohort study using time-to-event analysis to assess the risk of post-infection complications.

Pandemic-related social restrictions “caused significant lifestyle changes, raising concerns about their impact on physical and mental health through the deterioration of health-related behaviors, including reduced physical activity, sleep disturbances, and poor dietary habits,” the authors noted.

The findings were published in the International Journal of Infectious Diseases.

Higher risk of new-onset behavioral syndromes

The strongest predisposing factor for COVID-19 infection was an organic mental disorder, which carried 2.3 times the risk, followed by fungal disease and kidney failure, both posing 1.2 times the risk.

Our findings emphasize that mental and behavioral disorders are crucial health risk factors that should be addressed before and after infection.

Infected patients were at 3.5 times the risk for new-onset behavioral syndromes (eg, eating disorders, sleep disorders), followed by pulmonary heart disease and diseases of pulmonary circulation (3.0 times the risk) and sexually transmitted infections (2.8 times).

The authors noted that the underlying conditions that often co-occur in older adults (eg, cardiovascular disease) are risk factors for AD. 

“Moreover, as these comorbidities are risk factors for severe COVID-19, the overlapping presence of these risks in patients with AD may further increase their susceptibility to COVID-19,” they wrote. “Some studies have noted that delirium is a predictor of severe COVID-19.” 

“Our findings emphasize that mental and behavioral disorders are crucial health risk factors that should be addressed before and after infection,” they added.

• A Nipah cluster in India has raised alarms about the deadly henipavirus carried by fruit bats found in Southeast and South Asia. So far five hospital workers in Bengal state, India, have been infected. The workers—a doctor, three nurses, and another health care worker—are employed by a private hospital in Barasat. Official documents on the cluster are difficult to find, but media outlets report at least 100 people who were close contacts are quarantined and under observation. India has had a handful of small Nipah outbreaks in the past two decades. Since 2018, Kerala state has reported nine Nipah outbreaks. The Nipah case-fatality rate is estimated at 40% to 75%, but only limited human-to-human transmission has been shown.
• Six European countries, including the United Kingdom and Spain, have lost their measles elimination status as of yesterday, per the World Health Organization (WHO). Austria, Armenia, Azerbaijan, and Uzbekistan also lost their measles-free status. All countries have noted a rise in measles case since 2024 and a drop in routine vaccination against the virus. 
• Officials in Chicago have identified four Neisseria meningitidis infections in adults since January 15. Two of the case-patients were living in a temporary homeless shelter. One patient has died, and three were in the intensive care unit. All patients developed septicemia, and one patient also had meningitis. Even with antibiotic treatment, invasive meningococcal disease is fatal for 10% to 15% of patients.