News briefs

Mandating masks single most effective control measure in Melbourne’s COVID‐19 second wave

The mandating of masks during Melbourne’s COVID‐19 second wave in July 2020 was the single most important control measure and “turned the epidemic around”, new research from the Burnet Institute shows. The study, published in PLoS ONE, found a significant 20–30% reduction in the effective reproduction rate of the virus that correlated with that policy. The introduction of mandatory mask use by the Victorian Government on 22 July 2020, while Stage 3 restrictions were in place, turned an exponential increase in community transmission into an exponential decrease, almost overnight, the authors wrote. “We had a unique situation in Melbourne where masks were made mandatory as a single policy change, and compliance went from low use to very high use of masks in the community very rapidly,” they said. “It turned the epidemic around from case numbers that were increasing every day to a situation where we could see the numbers were getting back under control.” The study used thousands of images from The Age newspaper photo library of Melbourne community settings which showed mask usage rose from 43% before 22 July to 97% after that date. This matched survey data from the SCRUB study led by collaborators at Monash University where, 3 days before the policy change, 44% of participants reported “often” or “always” wearing masks compared with 100% “always” 4 days after masks were made mandatory. “The key finding from this study is that masks work. They are an effective way to reduce COVID‐19 transmission in the community. While using masks doesn’t mean that other restrictions to stop transmission may not be necessary, their use is a simple first step in our response to an outbreak. While we are confident that masks are highly effective indoors, we don’t know how much more effective they are indoors compared to outdoors. Importantly, given the growing evidence of outdoor transmission of the Delta variant, it makes sense that masks are worn both indoors and outdoors during a COVID‐19 outbreak.”

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0253510

Link between cognitive decline, bone loss and fracture risk in women

Researchers led by the Garvan Institute of Medical Research have discovered a link between cognitive decline and a faster rate of bone loss, and have found that cognitive decline over 5 years increased future fracture risk in women. The association between cognitive decline and bone loss was weaker in men. The study of individuals aged 65 years and older was carried out over 16 years and has revealed a potential new approach to help identify older people who may be at risk of fracture. The team used data from the Canadian Multicentre Osteoporosis Study (CaMos), which documented skeletal health in people living in the community since 1995. The researchers looked at cognitive and bone health measurements of 1741 women and 620 men aged 65 years and older, who had no symptoms of cognitive decline at the beginning of the study. “After adjusting for all other variables, we observed a significant link between a decline in cognitive health and bone loss in women. This association was weaker and not statistically significant in men,” said the authors. “Interestingly, we also saw that cognitive decline over the first 5 years was associated with a 1.7‐fold increase in future fracture risk in women in the subsequent 10 years. This was independent of the level of bone loss. Although this study, published in the Journal of Bone and Mineral Research, could not identify a causal link, it suggests that cognitive decline should be monitored along with bone health, as a decline in one may signal the need for increased vigilance in the other. The researchers added that the link could potentially be mediated by a third factor, such as oestrogen deficiency, which affects women after menopause and has been independently associated with both bone loss and cognitive decline.

https://asbmr.onlinelibrary.wiley.com/doi/10.1002/jbmr.4402