Research news and online first at the MJA

Vaccines could improve HIV infection treatment

Of the genetically diverse population of HIV-1 viruses present in an infected pregnant woman, the few she might transmit to her child during delivery are resistant to attack by antibodies in her blood, according to US research published in PLOS Pathogens. Antiretroviral drugs significantly reduce transmission risk, but these treatments are often not perfectly administered, particularly in resource-poor regions. Better understanding of how HIV-1 viruses are transmitted at delivery could inform new strategies to reduce infant HIV-1 infection. Previous research has suggested that antibodies in a mother might be less effective against certain genetic variants of HIV-1 in her body, thereby allowing for transmission of resistant viruses to her infant at delivery. The research team analysed HIV-1 viruses present in blood samples from 16 infants infected at delivery and their mothers; the samples had been collected in the early 1990s in the Women and Infants Transmission Study, before antiretroviral treatments were available. The researchers sequenced the HIV-1 variants, and for each mother–infant pair, they tested the sensitivity of both transmitted and non-transmitted viruses to antibodies concurrently present in the mother’s blood. The analysis revealed that most HIV-1 variants transmitted to the 16 infants at delivery were more resistant to the mothers’ antibodies than were non-transmitted variants. However, the transmitted viruses were sensitive to a separate panel of broadly neutralising HIV-1 antibodies, which can block infection of diverse HIV-1 strains. Genetic analysis uncovered particular sites in the membrane-proximal external region and variable loop 3 (V3) of the HIV-1 envelope glycoprotein may be important in mediating maternal antibody resistance. These findings could help guide development of a new vaccine for pregnant mothers with HIV-1 infection. Such a vaccine would boost maternal antibody attack of HIV-1 variants circulating in the blood, so that transmission risk is reduced when an infant is exposed to maternal blood during delivery.

Medication use increases in new dementia patients

An international study led by the University of Sydney has found that medication use increases in newly diagnosed patients with dementia, particularly unnecessary or inappropriate medications. Published in Journals of Gerontology: Medical Sciences, the longitudinal study of nearly 2500 people was conducted in collaboration with Yale University and the University of Kentucky. Around the world, 50 million people are estimated to live with dementia, with 425 000 in Australia currently. This has significant cost implications for health care systems, with recent estimates suggesting that dementia will cost Australia more than $15 billion per year. Dementia, including Alzheimer’s disease, is currently the second leading cause of death in Australia. “Our study found that following a diagnosis of dementia in older people, medication use increased by 11% in a year and the use of potentially inappropriate medications increased by 17%,” said lead author Dr Danijela Gnjidic, National Health and Medical Research Council Dementia Leadership Fellow and Senior Lecturer from the Faculty of Pharmacy and Charles Perkins Centre at the University of Sydney. Potentially inappropriate or unnecessary medications included sleeping tablets, pain drugs, depression drugs and proton pump inhibitors. “These medications are typically recommended for short term use, but are commonly used long term by people with dementia,” she said. “A number of reasons may account for this, including inadequate guidelines, lack of time during physician–patient encounters, diminished decision making capacity, difficulties with comprehension and communication, and difficulties in establishing goals of care. These findings are of major concern and highlight the importance of weighing up the harms and benefits of taking potentially unnecessary medications as they may lead to increased risk of side effects, such as sedation or drowsiness, and adverse drug events such as falls, fractures and hospitalisation. Further efforts are clearly needed to support better recognition of potentially inappropriate medications to minimise possible harms and warrant interventions to minimise such prescribing. For Australians living with dementia and their caregivers (who commonly are responsible for managing medications for people with dementia), the key is to communicate closely with GPs, pharmacists and other health professionals to make informed decisions and to practice good medicine management techniques to minimise the risk of side effects. Deprescribing unnecessary medications may improve an individual’s quality of life and can reduce unnecessary health care cost.”

What’s new online at the MJA

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Hiscock et al; doi: mja17.00434
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