(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays)
By Nancy Lapid
July 8 (Reuters) – We also report on a potentially important discovery on how malaria parasites infect cells, which could lead to future preventions, and a study that adds safety reassurance for combination flu/COVID vaccines.
IMPROVING HIP SURGERY OUTCOMES
A modern type of implant dramatically cuts dislocation risks after certain hip replacement surgeries, according to new data.
Instead of the traditional single ball-and-socket implant, the so-called dual-mobility device has a small ball rotating within a larger ball, which then rotates inside a metal cup, or socket. Using two moving surfaces instead of one in effect creates a larger diameter ball and increases the distance the ball must travel to escape the socket.
Researchers in Europe randomly assigned 1,600 people aged 65 or over to receive either a standard implant or a dual-mobility implant. All participants had fractured a thigh bone at the point where it connects with the hip joint.
One year after surgery, dislocation rates were 1.3% with the dual-mobility cup versus 4.2% with traditional hip replacement.
After accounting for individual risk factors, the odds of dislocation were 70% lower with the dual cup, according to a report of the study in The Lancet.
The overall risk of surgical complications was also lower with the new cup, although there were no differences in rates of implant infections, deaths or in quality of life during the first year.
“It is extremely painful when a hip replacement dislocates. When it occurs, patients require sedation or further surgery to realign the joint,” study co-author Dr. Nils Hailer of Uppsala University Hospital in Sweden said in a statement.
A dislocated joint impairs quality of life, as the patient may feel they can no longer really trust the implant, and so their participation in daily activities and their confidence in mobilizing is reduced, resulting in social withdrawal, according to a commentary published with the study.
Dual-mobility implants are more expensive than standard implants, but the researchers said the reduction in complications could offset the higher upfront cost and they are undertaking a full health economic analysis.
Manufacturers of the devices include Stryker, Smith+Nephew, and Johnson & Johnson’s DePuy Synthes unit.
“Surgeons are already familiar with both implant types, meaning the change could be implemented immediately within existing practice,” study co-author Dr. Xavier Griffin of Queen Mary University of London and Barts Health NHS Trust said in a statement.
MALARIA INFECTION THEORIES OVERTURNED
A new discovery overturns a decades-old assumption about how malaria parasites get into human red blood cells, researchers say.
Malaria parasites are known to force their way into blood cells through a ring-shaped protein structure called the moving junction. But how the structure actually behaves remained unknown, because it survives for less than 60 seconds, dissipating before anyone can get a close look.
As reported in the journal Cell, researchers were able to stall the single-cell Plasmodium falciparum parasites when they had partly broken into red blood cells. They lifted the intact complex out of the cell, froze it, and examined it under powerful microscopes.
They found that rather than simply attaching itself and acting as a passive doorway, as had been thought, the moving junction punctures and reshapes the host cell’s membrane, acting as a wedge to make it easier for the parasite to force its way through.
“We’ve known for decades that this structure is essential for the parasite to get into a cell, but not how it actually works,” study leader Chi-Min Ho of Columbia University Vagelos College of Physicians and Surgeons said in a statement. “Pulling it directly out of the parasite intact let us finally ask that question directly.”
After analyzing the structure, the researchers were able to design an experimental protein that blocks the invasion, a potential proof of concept for a new kind of antimalarial drug.
“Once we could see the target in its real setting, designing something to block it became a tractable problem,” Daphne Kaxiras, an MD-PhD student in Ho’s lab who led the protein design, said in a statement. “That’s the part we’re most eager to build on.”
GETTING FLU AND COVID SHOTS TOGETHER IS SAFE
Getting a flu shot and a COVID vaccine at the same time was not associated with a higher risk of adverse events compared with receiving the seasonal influenza vaccine alone, according to a new analysis.
Using data collected between 2022 and 2025 from the U.S. Department of Veterans Affairs healthcare system, researchers evaluated the 90-day rates of 46 different adverse events in more than 700,000 people who received both vaccines and roughly 1.8 million who received only the influenza vaccine.
The average age was close to 70 years.
Same-day vaccination against both viruses did not increase the risk for cardiovascular and thrombotic events, neurological disorders, immune-mediated disorders, or other serious or clinically meaningful adverse outcomes, the researchers reported in Annals of Internal Medicine.
This was true regardless of which version of the COVID-19 vaccine was used, or the year in which it was administered, they noted.
“The findings support the short-term safety of co-administration in older adults and may help inform ongoing vaccine policy discussions and individual risk–benefit assessments,” the researchers concluded.
The U.S. Centers for Disease Control and Prevention and several major medical organizations have previously said getting both vaccines together is a convenient way to stay protected without scheduling a second appointment.
During the term of U.S. Health Secretary Robert F. Kennedy Jr., a longtime anti-vaccine activist, the U.S. Food and Drug Administration has said it “cannot affirm that concurrent administration is both safe and effective.”
Moderna in April received European Commission approval for its flu and COVID combination shot in adults 50 and over. The shot is undergoing regulatory review in the United States.
(To receive the full newsletter in your inbox for free sign up here)
(Reporting by Nancy Lapid; Editing by Bill Berkrot)
Comments