While Omicron appears to be extremely transmissible and has been shown to have a greater ability to evade immunity from vaccination and prior infection, there is some evidence the Omicron variant may cause less severe disease.
In Gauteng, NICD hospital surveillance data show that 1904 COVID cases were admitted last week, and 177 COVID patients are currently in ICU with 51 ventilated as of yesterday. Nationwide, 13 147 new cases were detected with a positivity rate of 24.86%. While the fourth wave is still in the early stages, with a higher proportion of younger patients who develop less severe disease, anecdotal evidence points to reduced severity with the Omicron variant.
According to the Financial Times, preliminary data from the Steve Biko and Tshwane District Hospital Complex showed that on December 2 only nine of the 42 patients on the COVID ward, all of whom were unvaccinated, were being treated for the virus and were in need of oxygen. The remainder of the patients were COVID positive but asymptomatic and were being treated for other conditions.
“My colleagues and I have all noticed this high number of patients on room air,” said Dr Fareed Abdullah, an infectious disease doctor at the Steve Biko hospital and a director of the South African Medical Research Council.
“You walked into a COVID ward any time in the past 18 months… you could hear the oxygen whooshing out of the wall sockets, you could hear the ventilators beeping… but now the vast majority of patients are like any other ward.”
US chief medical adviser Dr Anthony Fauci remarked that initial South African data was “a bit encouraging regarding the severity”.
“Thus far, it does not look like there’s a great degree of severity to it,” he said. “But we’ve really got to be careful before we make any determinations.” Existing vaccines could provide “a considerable degree” of protection against Omicron, he added.
A small positive note for South Africa was Dr Fauci saying the administration is reevaluating the travel ban on eight southern African countries as more becomes known about Omicron and its spread.
“That ban was done at a time when we were really in the dark – we had no idea what was going on,” he said.
Current guidelines could be causing cow’s milk allergy to be over-diagnosed in infants, according to a new study.
Researchers analysed data on 1303 healthy infants who were exclusively breastfed until at least three months of age, and found that 38% and 74% of infants had multiple mild-to-moderate milk allergy symptoms – as defined by current allergy guidelines – at three months and 12 months old, respectively. By comparison, non-IgE-mediated cow’s milk allergy has a prevalence of less than 1% in children.
The researchers’ findings, which are published in Clinical & Experimental Allergy, suggest that following current guidelines may lead to over-diagnoses in infants by labelling normal infant symptoms as possible milk allergies.
“There is an assumption that the existence of a guideline is more beneficial than no guideline. However, well-meaning guidelines need to be supported by robust data to avoid harms from over-diagnosis that exceed the damage of missed and delayed cow’s milk allergy diagnoses that they are seeking to prevent,” the researchers wrote.
A number of commonly prescribed older antipsychotic drugs, and some newer ones, are associated with a significant increase in risk of breast cancer, according to a new study. The findings are published online in the Journal of Clinical Psychopharmacology.
Previous research uncovered the link between antipsychotic drug use, prescribed for a wide array of mental health problems, and breast cancer risk. This study compared newer antipsychotics to older drugs, and examined how the drugs affect prolactin levels, which have been associated with breast cancer. However, many antipsychotics elevate prolactin levels and can produce side effects such as menstrual cycle irregularities, abnormal breast milk production and abnormal breast tissue growth.
“Many women with psychiatric illnesses such as schizophrenia and bipolar disorder will take antipsychotics for decades, and they are essential to keeping symptoms in check,” said first author Tahir Rahman, MD. “But both older antipsychotic medicines and some newer drugs raise levels of prolactin and increase the risk of breast cancer, which is concerning. Our study confirms findings from a smaller European study that advised women and their doctors to first try drugs that don’t affect prolactin levels. We agree with that advice and believe psychiatrists should start to monitor prolactin levels in their patients taking antipsychotics.”
Antipsychotic drugs were classified into three categories, based on their established effects on prolactin. Category 1 included drugs associated with high prolactin levels, such as haloperidol, paliperidone and risperidone. Category 2 had mid-range effects and included iloperidone, lurasidone and olanzapine. Category 3 had low-effect drugs such as aripiprazole, asenapine, brexpiprazole, cariprazine, clozapine, quetiapine and ziprasidone.
Comparing the three drug categories to anticonvulsant drugs and lithium, the relative risk of breast cancer was 62% higher for women who took Category 1 drugs and 54% higher for those taking Category 2 drugs, whereas Category 3 antipsychotics were not associated with any increase in breast cancer risk.
“Certain drugs are known to elevate prolactin, and the women taking those drugs were more likely to have breast cancer,” Dr Rahman said. “But we didn’t detect any increased risk in women taking antipsychotics that don’t raise prolactin levels.”
In mouse models, prolactin can help weaken systems keeping precancerous lesions from becoming breast cancer. In humans, prolactin levels tend to be lower in women who have had more children at a younger age than in women who have fewer children or wait until they are older to do so.
In this study using data collected from 2012 through 2016, the research team performed a retrospective, observational study of breast cancer risk in women ages 18 through 64 who took antipsychotics.
The researchers identified which patients were treated for breast cancer during a 12-month period and matched that information to patients taking antipsychotic drugs. Of the 540 737 women in the database taking antipsychotics, only 914 were identified as having breast cancer – a significant number of whom were taking drugs known to increase prolactin.
“Antipsychotic medications can be lifesaving for patients who have psychotic episodes where they experience symptoms such as hallucinations and delusions,” Dr Rahman said. “In recent years, the drugs have been approved to treat other conditions, too, including depression and bipolar disorder. As those high-prolactin agents are used more widely, the number at risk could increase. We’ve been advising against using these high-prolactin agents in women who already have breast cancer, but we’d like to investigate whether keeping prolactin levels lower even might prevent some of these cancers.”
In another recent study, the antipsychotic drug aripiprazole did not increase prolactin levels in women and that a few women who began the study with high prolactin levels experienced decreases in prolactin levels after 12 weeks of treatment.
Those findings, combined with preclinical evidence of the anticancer effects of some antipsychotics, have inspired Dr Rahman and colleagues to propose repurposing some antipsychotic drugs in the fight against breast cancer.
“We don’t want to alarm patients taking antipsychotic drugs for life-threatening mental health problems, but we also think it is time for doctors to track prolactin levels and vigilantly monitor their patients who are being treated with antipsychotics,” Dr Rahman said.
A novel study has isolated powerful anticoagulants from the saliva of ticks, which may have reduced potential for bleeding.
Blood-feeding animals rely on specific molecules in their saliva to overcome defence mechanisms of their mammalian hosts for successful survival. The saliva of ticks, for example, contains molecules that can prevent blood from clotting, and which can also suppress inflammation or immune response to enable continuous feeding on the same bite site for days, sometimes undetected by the host. The harmful effects of these parasites can actually be harnessed for medical treatments.
In their paper, published in Nature Communications, the authors explain how the cardiovascular team developed a series of thrombin inhibitors to be potent anticoagulants based on sequences of inhibitors of blood coagulation enzyme thrombin found in the tropical bont tick Amblyomma variegatum.
The team developed a series of thrombin inhibitors to be powerful anticoagulants.
Anticoagulants are used in conditions where there is an increased propensity to form blood clots in our body depriving blood supplies to important tissues and organs, otherwise known as thrombosis. These drugs are needed in many diseases caused by blood clots including heart attacks, strokes, deep vein thrombosis, pulmonary embolism and even some severe complications caused by SARS-CoV-2 infection.
These next-generation anticoagulants will now need to be tested in human trials to determine if they can effectively counteract clotting without the bleeding side effects of currently available anticoagulants.
Researchers have identified an important mediator of youthfulness in mouse muscle, which explains the ‘rejuvenating’ blood transfusions effect between young and old mice. The discovery could also lead to new therapies for age-related muscle loss.
Published in Nature Aging, the study showed that circulating shuttles called extracellular vesicles, or EVs, deliver genetic instructions for the longevity protein known as Klotho to muscle cells. Reduced muscle function and repair in old mice may be driven by aged EVs, which carry fewer instructions than those in young animals.
The findings help further as to understanding why muscle regeneration capacity diminishes with age.
“We’re really excited about this research for a couple of reasons,” said senior author Dr Fabrisia Ambrosio. “In one way, it helps us understand the basic biology of how muscle regeneration works and how it fails to work as we age. Then, taking that information to the next step, we can think about using extracellular vesicles as therapeutics to counteract these age-related defects.”
Decades of research have shown that when old mice are given blood from young mice, youthful features are restored to many cells and tissues. But until now, it was unclear which components of young blood confer these rejuvenating effects.
“Amrita Sahu releaseWe wondered if extracellular vesicles might contribute to muscle regeneration because these couriers travel between cells via the blood and other bodily fluids,” said lead author Dr Amrita Sahu. “Like a message in a bottle, EVs deliver information to target cells.”
Ambrosio and her team collected serum from young mice and injected it into aged mice with injured muscle. Mice that received young serum showed enhanced muscle regeneration and functional recovery compared to those that received a placebo treatment, but the serum’s restorative properties were lost when EVs were removed, indicating that it is these vesicles which deliver the beneficial effects of young blood.
The researchers then found that EVs deliver genetic instructions, or mRNA, encoding the anti-ageing protein Klotho to muscle progenitor cells, important stem cells for muscle regeneration. EVs collected from old mice carried fewer copies of Klotho instructions than those from young mice, causing muscle progenitor cells to produce less of this protein.
With advancing age, muscle doesn’t recover from damage as well because scar tissue is laid down. In earlier work, Ambrosio and her team showed that Klotho is an important regulator of regenerative capacity in muscle progenitor cells and that this protein declines with age.
The new study shows for the first time that age-related shifts in EV cargo contribute to depleted Klotho in aged stem cells, suggesting that EVs could be developed into novel therapies for healing damaged muscle tissue.
“EVs may be beneficial for boosting regenerative capacity of muscle in older individuals and improving functional recovery after an injury,” said Ambrosio. “One of the ideas we’re really excited about is engineering EVs with specific cargoes, so that we can dictate the responses of target cells.”
Beyond muscles, EVs also could help reverse other effects of ageing. Previous work has demonstrated that young blood can boost cognitive performance of aged mice.
