Research news in brief

Second-wave COVID-19 mortality dropped in (most) wealthier zones

Wealthier northeastern US states and Western European countries tended to have significantly lower mortality rates during the second-wave of COVID-19 infections, according to research from the University of Sydney and Tsinghua University. However, the pattern was not as general as expected, with notable exceptions to this trend in Sweden and Germany. The researchers took a “time series of infection rates by country, applied an algorithmic approach to chop it up into first and later waves and then did some relatively simple optimisation and calculations to determine two different mortality numbers”. The mortality rate of the massive European second wave turned out to be less severe than expected, at least with respect to reported cases and deaths. The researchers wanted to know how big that drop in mortality was and how it differed between countries. Using a sophisticated mathematical model, each country in Europe and each state in the US was given a mortality data point for the first and second waves. Comparing these figures gives each country or state a data point or mortality ratio. In Belarus, for example, the mortality rate increased during its second wave, while Ukraine and Moldova were still in their first wave as of the end of November 2020. The researchers discovered this was very different from the Netherlands, Belgium, France and other countries that drastically reduced their mortality rates – at least with respect to reported numbers – between their first and second waves. The differences tended to be less marked in the US, with a flatter outcome. However, states such as New York, New Jersey and Connecticut, which were particularly hard hit in the first wave, saw second-wave mortality rates decline in line with many western European countries. Countries that experienced a more than 10-fold decrease in mortality in Europe were Belgium (11.25), Denmark (14.28), France (13.67) and the Netherlands (16.17). The research was published in Chaos.

Scientists make tear glands in a dish cry

Stem-cell-derived organoids that swell up with tears could shed light on the biology of crying and dry eye disease, suggests a study published in Cell Stem Cell. The researchers generated 3D mouse and human lacrimal gland organoids derived from adult stem cells by adapting a protocol they previously used for other organs. The organoids could be expanded over multiple months and recapitulated structural, transcriptional, and functional features of the lacrimal gland epithelium. The organoids swelled up like a balloon after being exposed to the neurotransmitter noradrenaline, which triggers tear secretion. The researchers leveraged the mouse organoids to explore the role of Pax6 – the master control gene for eye development – in adult tear glands. By using CRISPR/Cas9 genome editing to delete Pax6, they discovered that the gene is an important contributor to the maturation of adult lacrimal gland epithelial cells. These particular organoids could provide valuable insights into potential treatments for Sjögren’s syndrome because PAX6 deficiency has been observed in the eye tissue of these patients. Using single-cell mRNA sequencing, the researchers also examined poorly understood cellular features and origins of tear components in the lacrimal gland. Their single-cell atlas revealed new tear components and demonstrated that ductal and acinar cells in the human lacrimal gland secrete a different repertoire of tear components. To test the potential of the organoids for regenerative medicine, the researchers then transplanted human organoid cells into mouse lacrimal glands. Two weeks later, the human organoid cells formed duct-like structures that remained in the lacrimal gland for at least 2 months. Engrafted organoids appeared to self-organise, and some cells were proliferating up to 2 months after transplantation. Moreover, the researchers detected tear proteins inside the ducts formed by the transplanted cells.

Pandemic may offer opportunity to wind back unnecessary care

A systematic review of more than 80 scientific studies from around the world has found a pandemic-induced median reduction of 37% in the use of health care services, such as visits to emergency departments. Published in BMJ Open, the review summarised 81 studies from the first 4 months of the COVID-19 pandemic and found similar reductions across all forms of health care, from hospital visits to diagnostic tests and treatments. The review also found that in many cases, the reductions in the use of health care were greater for those with milder conditions, such as visits to emergency departments for abdominal pain. A global team from Canada, Sweden and Australia conducted the large review, including from the Australian Commission on Safety and Quality in Health Care and Health Consumers Queensland. The systematic review was led by Bond University’s new Institute for Evidence-Based Healthcare. The study concludes that: “While addressing unmet need remains a priority, studies of health impacts of reductions may help health systems reduce unnecessary care in the post-pandemic recovery.” The findings are similar to those published by the NSW Agency for Clinical Innovation in December, which also expressed concern about people missing needed care, but noted that falls in low value care could be beneficial.

Preschoolers’ extensive electronic media use linked to emotional and behavioural issues

Preschoolers’ extensive use of electronic media, including game consoles, mobile phones, and tablets, is linked to a heightened risk of emotional and behavioural problems by the age of 5 years, according to a study published in BMJ Open. Preschoolers’ use of mobile phones and tablets tripled between 2013 and 2017, with recent studies indicating that many 4-year-olds now play games, use apps, or watch videos on them every day. The researchers drew on participants in the Finnish CHILD-SLEEP longitudinal birth cohort study, which has regularly tracked children’s health and/or psychological wellbeing from before birth (32 weeks) up to the age of 5 years, via parental questionnaires. The final analysis included 699 children (333 girls; 366 boys) for whom complete health and questionnaire data were available from the age of 18 months onwards. Around two-thirds of the children (68%) were in full-time day care; nearly two-thirds of the parents (64%) were educated to degree level. Parents reported how much time their child spent using electronic media at 18 months and 5 years of age, both during the week and at the weekend. Parents were specifically asked how many hours their child watched programs on television or other devices, and (at 5 years) how many hours their child played games on a computer, games console, mobile phone, tablet or other device. The responses were used to calculate a daily average for program watching, game playing, and total screen time. At 18 months of age, the toddlers spent an average of 32 minutes per day on electronic media devices. By the age of 5 years, this had increased to 114 minutes per day. Nearly one in four children (23%) spent more than an hour on total screen time every day at 18 months of age; by the age of 5 years, this percentage had risen to 95%. By the age of 5 years, more than two-thirds (67%) watched programs for more than an hour a day and around one in ten (11%) spent more than an hour a day gaming. Maximum recommended daily use of electronic media for preschoolers is 60 minutes. When the children were 5 years old, validated questionnaires were used to assess the prevalence of “psychosocial symptoms” — emotional and behavioural issues, short attention span, hyperactivity, and difficulties making and keeping friends. Extended use of all electronic media at 18 months was associated with a 59% heightened risk of peer relationship problems by the age of 5 years, but nothing else. By the age of 5 years, extensive electronic gaming was associated only with a heightened risk of hyperactivity, which disappeared after taking account of influential factors. But lengthy program viewing was associated with a heightened risk of several psychosocial problems. Excess total screen time at 5 years of age was associated with a heightened risk of attention and concentration difficulties, hyperactivity and impulsivity, and emotional and behavioural problems. This is an observational study, and as such, can’t establish cause.