Medical Minutes
At-home testing for COVID infection
Researchers have developed a new type of multiplexed test with a low-cost sensor that may enable the at-home diagnosis of a COVID-19 infection through rapid analysis of small volumes of saliva or blood, without the involvement of a medical professional, in less than 10 minutes. One feature of the COVID-19 virus that makes it so difficult to contain is that it can be easily spread to others by a person who has yet to show any signs of infection. The carrier of the virus might feel perfectly well and go about their daily business.
A crucial part of the global effort to stem the spread of the pandemic, therefore, is the development of tests that can rapidly identify infections in people who are not yet symptomatic. Now, Caltech researchers have developed a new at-home 10-minute test. Previously, they had developed wireless sensors that can monitor conditions such as gout, as well as stress levels, through the detection of extremely low levels of specific compounds in blood, saliva or sweat.
“In as little as a few minutes, we can simultaneously check these levels, so we get a full picture about the infection, including early infection, immunity and severity,” said lead investigator Wei Gao, who is an assistant professor in the department of medical engineering at Caltech in Pasadena, California.
Established COVID-testing technologies usually take hours or even days to produce results. Those technologies also require expensive, complicated equipment. Gao’s system is simple and compact. So far, the device has been tested only in the lab with a small number of blood and saliva samples obtained for medical research purposes from individuals who have tested positive or negative for COVID-19. Though preliminary results indicate that the sensor is highly accurate, larger-scale testing with real-world patients will now be required to determine its full accuracy.
New case shows why wearing a mask really matters
New research from the University of Georgia dramatically highlights how important it is to wear a mask in enclosed indoor spaces. You could say in this case, getting on the wrong bus really mattered. Researchers were able to link a community outbreak of COVID-19 in China to a source patient who likely spread the virus to fellow bus riders through the bus’s air conditioning system.
“The possibility of airborne transmission has long been suspected, but with limited empirical evidence. Our study provided epidemiologic evidence of transmission over long distances, which was likely airborne,” said lead study author Ye Shen, who is an associate professor of epidemiology and biostatistics at the University of Georgia’s College of Public Health.
Shen and his co-authors worked with epidemiologists from two regional Centers for Disease Control and Prevention in China to trace infections following a large outdoor worship event in Zhejiang province. Some of the attendees took two buses to the event creating a unique natural experiment for the researchers. Both buses had closed windows and had air conditioning running, but one bus carried a patient infected with the virus, and the other did not, said study co-author Changwei Li, who is an associate professor of epidemiology at Tulane University, New Orleans, Louisiana.
Of the passengers who later got sick, the majority of them rode on the same bus as the source patient. Even though the two groups later mixed in with the larger crowd at the worship event, the number of new cases attributed to the event were much lower, suggesting that the bus was the major point of transmission.
Further, some of the bus passengers who later showed symptoms of COVID-19 were not sitting close to the infected passenger. These findings highlight scenarios where COVID-19 could be spread through fine aerosol particles being circulated in an enclosed space, and as the weather turns colder. It is hoped that these new findings will persuade more people to wear face masks in public areas, particularly in indoor spaces.
“Understanding the transmission routes of COVID-19 is critical to contain the pandemic, so that effective prevention strategies can be developed targeting all potential transmission routes,” said Shen. “Our findings provide solid support for wearing face coverings in enclosed environments with poor ventilation.”
Walking daily for a better tomorrow
Grab your walking shoes. Just taking a daily stroll may do much more than you ever realized, especially during the COVID pandemic. Two studies published this year showed that older adults may be able to live longer, healthier lives by increasing physical activity that doesn’t have to be strenuous to be effective.
The studies, which were presented at the American Heart Association’s Epidemiology and Prevention/Lifestyle and Cardiometabolic Health Scientific Sessions 2020, showed that older adults were 67% less likely to die of any cause if they spent at least 150 minutes per week doing moderate to vigorous physical activity compared to those who did not engage in more than 150 minutes per week of moderate to vigorous physical activity.
The new data also demonstrated that among the participants (average age of 69) physical activity doesn’t have to be strenuous to be effective. The researchers observed that each 30-minute interval of light-intensity physical activities, such as doing household chores or casual walking, was associated with a 20% lower risk of dying from any cause. Conversely, every additional 30-minutes of being sedentary was related to a 32% higher risk of dying from any cause.
This investigation evaluated physical activity levels of 1,262 participants from the ongoing Framingham Offspring Study. Participants were an average age of 69 (54% women), and they were instructed to wear a device that objectively measured physical activity for at least 10 hours a day, and for at least four days a week between 2011 and 2014.
Researchers found that women who walked 2,100 to 4,500 steps daily reduced their risk of dying from heart attacks, heart failure, stroke and other cardiovascular diseases by up to 38% compared to women who walked less than 2,100 daily steps. The women who walked more than 4,500 steps per day reduced their risk by 48%. The cardio-protective effect of more steps per day was present even after the researchers took into consideration heart disease risk factors, such as obesity, elevated cholesterol, blood pressure, triglycerides and/or blood sugar levels, and was not dependent on how fast the women walked.
“Despite popular beliefs, there is little evidence that people need to aim for 10,000 steps daily to get cardiovascular benefits from walking. Our study showed that getting just over 4,500 steps per day is strongly associated with reduced risk of dying from cardiovascular disease in older women,” said lead study author Andrea Z. LaCroix, who is the chief of epidemiology at the University of California, San Diego.
She said taking more steps per day, even just a few more, is achievable, and step counts are an easy-to-understand way to measure how much we are moving. The study included more than 6,000 women enrolled in the Women’s Health Initiative and each participant wore an accelerometer on their waist to measure physical activity and participants were followed for up to seven years for death due to heart disease.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute. He can be reached at medicalminutes@gmail.com.
John Schieszer is an award-winning national journalist and radio and podcast broadcaster of The Medical Minute.
