Researchers have found that greater grip strength in older women reduces mortality risk, regardless of weight change, suggesting that mobility and strength support should have more focus than weight loss in this group.
Grip strength and short physical performance battery (SPPB) are measures of physical functioning. Grip strength assesses strength of grip alone, whereas SPPB is a cumulative score considering three components: balance test, timed walk, and chair stands.
Previous studies have shown a link between increased grip strength and lower all-cause mortality. SPPB considers timed walk, balance test, and chair stands, and is associated with CVD risk in older women. However, studies of the effects of weight loss on grip strength which evaluated participants before and after weight loss interventions have shown inconsistent results.
In a study published in the Journal of the American Geriatrics Society, researchers followed 5039 older women for an average of 5.4 years. They found that loss of 5% or more body weight was associated with a 66% higher risk of dying. However, there was no association of weight gain with mortality.
The researchers also found that higher grip strength and better lower extremity functioning were associated with lower risks of death during follow-up, regardless of weight change.
“Our findings support increasing efforts to improve mobility and muscle strength in older women and less focus on long-term weight loss in this population,” said lead author Lisa Underland, DO, of Children’s Hospital at Montefiore.
Basal ganglia are deep grey matter structures in the brain involved in the control of posture and voluntary movements, cognition, behaviour, and motivational states. Several conditions are known to affect basal ganglia during childhood, but many questions remain.
In a study that included 62 children with basal ganglia diseases who were followed for two years, investigators identified multiple genetic aetiologies including mitochondrial diseases (57%), Aicardi–Goutières syndrome (20%), and single-gene causes of dystonia and/or epilepsy (17%) mimicking Leigh syndrome. Radiological abnormalities included T2-hyperintense lesions (n=26) and lesions caused by calcium or manganese mineralisation (n=9).
The researchers identified three clusters: the pallidal, neostriatal, and striatal, plus the last including mtDNA defects in the oxidative phosphorylation system with prominent brain atrophy. Mitochondrial biomarkers showed poor sensitivity and specificity in children with mitochondrial disease, whereas an interferon signature was observed in all patients with Aicardi–Goutières syndrome.
Radiological imaging tests also revealed several characteristics in patients that could help lead to an earlier diagnosis of basal ganglia diseases.
With the Omicron variant now dominating, a local study showed that, if confirmed, testing for COVID could be more accurate with much easier saliva sampling.
University of Cape Town researchers reported in a paper uploaded to medRxiv[PDF] that in Omicron cases, saliva samples yielded more accurate results in PCR analyses compared to nasal swabs.
With the Delta variant, on the other hand, nasal swabs were more accurate, according to the group, led by Diana Hardie, MBChB, MMedPath, who also heads the diagnostic virology laboratory at Groote Schuur Hospital.
The findings came from an analysis of 382 patients tested at Groote Schuur from August through this month, with viral whole-genome sequencing performed on isolates from those with positive results.
All patients had both saliva and mid-turbinate nasal samples taken for RT-PCR analysis. The ‘gold standard’ for positivity in the study was detection of SARS-CoV-2 RNA with either swab.
For the Delta variant, the positive percent agreement for each sampling method, in comparison with this ‘gold standard’, was 71% for saliva and 100% for the nasal swabs. But Omicron reversed the trend, with 100% agreement between saliva samples and the gold standard, but only 86% for nasal swabs.
COVID testing has used nasal swabs as standard since the discovery of the virus, but that may no longer be appropriate in an Omicron-dominated pandemic landscape, the authors concluded.
“These findings suggest that the pattern of viral shedding during the course of infection is altered for Omicron with higher viral shedding in saliva relative to nasal samples resulting in improved diagnostic performance of saliva swabs,” Hardie and colleagues wrote.
They noted, as have others, that Omicron is distinguished by “more than 50 distinct mutations.” While these increased infectivity, they could also have other effects, including the tissues it may prefer to infect.
The researchers cited a recent unpublished lab study from Hong Kong indicating that Omicron preferentially infects the upper airway. Not only does it suggest Omicron is less lethal, but also that the many mutations confer “altered tissue tropism.”
However, saliva sampling is not as simple as it sounds. At Groote Schuur, patients were instructed to swab the inside of the mouth for a total of at least 30 seconds. They were also told not to eat, drink, smoke, or chew anything for at least 30 minutes beforehand.
While most of the COVID testing kits in the US and elsewhere rely on nasal swabs, any change to saliva sampling would take months – by which time Omicron may have been displaced by another variant.
A surprising discovery in hedgehogs showed that a variant of the MRSA superbug appeared in nature well before antibiotics use in humans and livestock, which has traditionally been blamed for its emergence.
Staphylococcus aureus first developed resistance to the antibiotic methicillin around 200 years ago, according to a large international study which has traced the genetic history of the bacteria.
The finding comes from research showing that up to 60% of hedgehogs in Denmark and Sweden carry a type of MRSA called mecC-MRSA. The new study also found high levels of MRSA in swabs taken from hedgehogs across their range in Europe and New Zealand. Their findings were published in the journal Nature.
The researchers believe that antibiotic resistance evolved in S. aureus as an adaptation to having to exist on hedgehog skin next to the fungus Trichophyton erinacei, which produces its own antibiotics. The discovery of this centuries-old antibiotic resistance predates antibiotic use in medical and agricultural settings.
“Using sequencing technology we have traced the genes that give mecC-MRSA its antibiotic resistance all the way back to their first appearance, and found they were around in the nineteenth century,” said Dr Ewan Harrison, a senior author of the study.
He added: “Our study suggests that it wasn’t the use of penicillin that drove the initial emergence of MRSA, it was a natural biological process. We think MRSA evolved in a battle for survival on the skin of hedgehogs, and subsequently spread to livestock and humans through direct contact.”
Antibiotic resistance in human pathogens was previously thought to be a modern phenomenon, driven by the clinical use of antibiotics. Antibiotic misuse is now accelerating the process, with antibiotic resistance rising dangerously worldwide.
Since nearly all antibiotics used today arose in nature, the researchers say it is likely that resistance to them already exists in nature too. Overuse of any antibiotic in humans or livestock will favour resistant strains of the bacteria, causing it to lose effectiveness over time.
“This study is a stark warning that when we use antibiotics, we have to use them with care. There’s a very big wildlife ‘reservoir’ where antibiotic-resistant bacteria can survive – and from there it’s a short step for them to be picked up by livestock, and then to infect humans,” said Professor Mark Holmes, a senior author of the report.
In 2011, mecC -MRSA was identified in human and dairy cow populations, which was assumed to have arisen due to the large number of antibiotics cows are routinely given.
MRSA was first identified in patients in 1960, and around 1 in 200 of all MRSA infections are caused by mecC-MRSA. Due to its resistance to antibiotics, MRSA is much harder to treat than other bacterial infections. The World Health Organization now considers MRSA one of the world’s greatest threats to human health.
Human infections are rare with mecC-MRSA however, even though it has been present in hedgehogs for more than 200 years.
South Africa’s easing of COVID regulations at the end of 2021 set a new trend in how countries are choosing to manage the pandemic. In an article for The Conversation, Wits University’s Professor Shabir Madhi and colleagues reflect on the boldness – and the risks.
In a significant departure, the government is choosing a new, more pragmatic approach while keeping an eye on severe COVID and threats to health systems. This reflects a willingness to “live with the virus” without causing further damage to the economy and livelihoods, especially in a resource-constrained country.
Prof Madhi and colleagues hope that “the government continues to pursue this approach and doesn’t blindly follow policies that are not feasible in the local context, and ultimately yield nominal benefit.”
This more nuanced approach is a stark contrast to reflexive restrictions in response to rising case rates, suggesting the government has listened to commentary saying that the focus should be on whether health systems are under threat.
A high level of population immunity guides this approach. A sero-survey in Gauteng, just prior to the onset of the Omicron wave indicated that 72% of people had been infected over the course of the first three waves. Sero-positivity was 79% and 93% in COVID unvaccinated and vaccinated people aged over 50: a group that had previously made up a high percentage of hospitalisations and deaths.
The sero-survey data show that immunity against severe COVID in the country has largely evolved through natural infection over the course of the first three waves and prior to the advent of vaccination. This has, however, come at the massive cost of 268 813 deaths based on excess mortality attributable to COVID
Antibody presence is a proxy for underlying T-cell immunity which appears to play an important role in reducing the risk of infection progressing to severe COVID. Current evidence indicates that such T cell immunity, which has multiple targets and even more so when induced by natural infection, is relatively unaffected even by Omicron’s many mutations and likely lasts more than a year. This sort of underpinning T-cell immunity protecting against severe disease should provide breathing space for at least the next 6–12 months, and possibly further.
Despite Omicron’s anti-spike evasion, vaccine and natural infection induced T-cell immunity has been relatively preserved. This could explain the uncoupling of case rate to hospitalisation and death rates. Omicron’s mutations also appear to make it predisposed to infecting the upper rather than the lower airway, reducing the likelihood of progressing to severe disease.
In the meantime, they stress that greater vaccine uptake is ensured, along with boosters for high-risk groups.
Additionally, since low test rates mean only 10% of infections are actually documented in SA , isolation and quarantine are ineffective and a more pragmatic approach is necessary, the authors argued.
As the average person in South Africa could have 20 close contacts per day, contact tracing is of little value, and even symptomatic cases are most infectious in the pre-symptomatic and early symptomatic phase. The fact that three quarters of the SA population were infected over the course of the first three waves demonstrates how ineffective contact tracing and quarantine is. They recommend that certain non-pharmacological interventions should be gradually dropped, especially hand hygiene and superficial thermal screening, while outdoor events should be allowed. Rather, government focus should remain on masking in poorly ventilated spaces and ensuring proper ventilation.
Mandatory vaccinations are still on the radar, since as well as the added risk to others that unvaccinated pose, there is the greater pressure they place on the health systems when they are hospitalised for COVID.
Attention also needs to be given to the management of incidental COVID infections in hospitals. The Department of Health guidance needs to be adapted to manage these patients with the appropriate level of care for the primary reason they were admitted. And patients with severe COVID disease require additional care and expertise to improve their outcomes.
Finally, an evaluation of both vaccination status and underlying immune deficiency needs to become a key element of the workup of hospitalised patients with severe COVID.
The authors stressed the need to minimise hospitalisations and deaths, without damaging livelihoods. SA’s Omicron wave death rate is about a tenth that of Delta, on par with pre-COVID seasonal influenza deaths – 10 000 to 11 000 per annum. TB caused an estimated 58 000 deaths in 2019.
While future variants are unpredictable, there is a trend towards lower rates of hospitalisation and death, especially if vaccine coverage can be increased to 90%, particularly in the over-50 age group. Omicron’s high infection rate will likely also contribute to future protection against COVID.
They note that while there is a risk of new variants, failure to change the pandemic mindset is another risk, as Omicron signals the end of COVID’s epidemic phase.
Past practices have had little effect, the authors concluded, and it is something that the SA government appears to have realised. Despite all the severe lockdowns, SA still suffered a high COVID death rate of 481 per 100 000.
