Trends in Anesthesiology

A Centers for Disease Control and Prevention (CDC) report released in September evaluated vaccine effectiveness during the March-September Southern Hemisphere influenza season.

Based on data contributed by Argentina, Brazil, Chile, Paraguay, and Uruguay on 2,780 severe acute respiratory infection (SARI) patients hospitalized during March 27-July 9, 2023, the adjusted vaccine effectiveness against SARI hospitalization associated with any influenza virus during the 2023 Southern Hemisphere season was 51.9% (95% CI: 39.2%-62.0%), including 55.2% (95% CI: 41.8%-65.5%) against the predominating A(H1N1) pdm09. These early, interim estimates, provided before the expected end of seasonal influenza virus circulation, suggest that vaccination substantially reduced the risk for severe influenza illnesses, underscoring the benefits of influenza vaccination.

In anticipation of Northern Hemisphere influenza virus circulation, the World Health Organization and CDC recommend that health authorities encourage health care providers to administer annual influenza vaccination to all eligible persons, particularly emphasizing the importance of vaccination for persons at increased risk for severe outcomes (e.g., very young children, persons with preexisting health conditions, including pregnant women, and older adults).

Source: asamonitor.pub/3sTFS9Z

In a randomized trial published in The Lancet Oncology, Mayo Clinic Comprehensive Cancer Center researchers uncovered evidence supporting a shorter treatment time for patients with breast cancer. The study compared two separate dosing schedules of pencil-beam scanning proton therapy, the most advanced type of proton therapy, known for its precision in targeting cancer cells while preserving healthy tissue to reduce the risk of side effects.

Survival rates for breast cancer continue to improve due to advances in diagnosis and treatment, leading to increasing emphasis on reducing the long-term toxicity of cancer treatment, including radiotherapy.

Prior to this study, all patients treated with proton postmastectomy radiotherapy (PMRT) had received a conventional 25- 30-day course delivered five days per week over five to six weeks. The researchers hoped to demonstrate that condensing the course of proton beam therapy, a form of particle therapy that could spare the heart and lungs from radiation damage, may result in a similar side effect profile.

In the study, 82 patients with indications for PMRT, many of whom had prior breast reconstruction, were randomized to either conventional fractionation (fractions of radiation dose) administered in 25 days, or a condensed 15-day hypofractionated schedule. With hypofractionation, a larger dose of radiotherapy is delivered with each treatment, allowing all radiotherapy to be completed in just three weeks. The investigators found that both conventional and hypofractionated proton therapy resulted in excellent control of the cancer while sparing surrounding normal tissue. Further, complication rates were comparable between the two study groups.

“The study provides the first prospective data supporting the use of shorter-course proton PMRT, including in patients with immediate breast reconstruction, and the first mature results of a randomized trial in the field of breast particle therapy,” said Robert Mutter, MD, a radiation oncologist and physician-scientist at Mayo Clinic Comprehensive Cancer Center. “We can now consider the option of 15 days of therapy with patients based on the similar treatment outcomes observed as the longer conventional course. Of note, the short course actually resulted in reduced skin side effects during and after treatment.”

Importantly, the researchers noted that the new schedule spares patients additional inconvenience, cost, and other burdens associated with the longer regimen. As there are a limited number of proton therapy facilities in the United States and the world, Dr. Mutter adds that demonstrating the safety and feasibility of the shorter treatment course could result in greater access to proton beam technology for difficult-to-treat breast cancer cases.

Source: asamonitor.pub/3Zdgxnm

New “hypervirulent” strains of the bacterium Klebsiella pneumoniae have emerged in healthy people in community settings, prompting a National Institutes of Health (NIH) research group to investigate how the human immune system defends against infection.

After exposing the strains to components of the human immune system in a laboratory “test tube” setting, scientists found that some strains were more likely to survive in blood and serum than others, and that neutrophils are more likely to ingest and kill some strains than others. The study, published in mBio, was led by researchers at NIH’s National Institute of Allergy and Infectious Diseases (NIAID).

“This important study is among the first to investigate interaction of these emergent Klebsiella pneumoniae strains with components of human host defense,” Acting NIAID Director Hugh Auchincloss, MD, said.

More than a century ago, scientists identified Klebsiella pneumoniae as a cause of serious, often fatal, human infections, mostly in people already ill or with weakened immune systems and especially people in hospitals. Over a span of many decades, some strains developed resistance to multiple antibiotics and became difficult to treat. This bacterium, often called classical Klebsiella pneumoniae, or cKp, ranks as the third most common pathogen isolated from hospital bloodstream infections. Certain other Klebsiella pneumoniae strains cause severe infections in healthy people in community settings (outside of hospitals) even though they are not multidrug-resistant. They are known as hypervirulent Klebsiella pneumoniae, or hvKp. More recently, strains with both multidrug resistance and hypervirulence characteristics, so-called MDR hvKp, have emerged in both settings.

NIAID scientists have studied this general phenomenon before. In the early 2000s they observed – and actively investigated – virulent strains of methicillin-resistant Staphylococcus aureus (MRSA) bacteria that had emerged in U.S. community settings and caused widespread infections in otherwise healthy people.

Now, the same NIAID research group at Rocky Mountain Laboratories in Hamilton, Montana, is investigating similar questions about the new Klebsiella strains, such as whether the microbes can evade human immune system defenses. Their findings were unexpected: the hvKp strains were more likely to survive in blood and serum than MDR hvKp strains. Neutrophils had ingested less than 5% of the hvKp strains, but more than 67% of the MDR hvKp strains – most of which were killed.

The researchers also developed an antibody serum specifically designed to help neutrophils ingest and kill two selected hvKp and two selected MDR hvKp strains. The antiserum worked, though not uniformly in the hvKp strains. These findings suggest that a vaccine approach for prevention/treatment of infections is feasible.

Source: asamonitor.pub/3RjkJ37