US cell phone data: Staying home amid lockdowns may stem COVID-19
US counties with large declines in cell phone activity at workplaces, transit stations, and stores and concomitant increases in home activity during COVID-19 lockdowns had lower rates of coronavirus infections 5, 10, and 15 days later, according to a study published today in JAMA Internal Medicine.
The researchers made 22,124 to 83,745 daily observations of cell phone location data from 949 to 2,740 counties, depending on data availability, from Jan 22 to May 11 and compared them with COVID-19 growth rates.
Growth of COVID-19 cases was 45.5% lower in counties in the lowest quartile of activity in retail stores than in those with the highest quartile, while counties with the most residential activity had a 19% lower COVID-19 growth rate at 15 days than those with the least.
Overall, cell phone activity outside the home increased roughly 0.5% compared with in-home activity per day that the stay-at-home measures were in place, suggesting waning adherence over time.
After adjusting for county population, case rates, and state-level factors, rural counties had smaller reductions in cell phone activity at workplaces, transit stations, and stores and greater reductions in visits to parks and home activities than did urban counties.
Counties in states with higher proportions of older adults, children, black residents, and people living in poverty; more per-capital hospital beds; and lower population density had the smallest reductions in workplace cell phone activity. Conversely, county residents stayed home more in states with a lower proportion of older adults, higher population density, greater economic productivity, lower rates of the uninsured, greater proportion spent on healthcare, fewer people living in poverty, and higher case rates.
“Reductions in workplace activity and increases in residential activity were higher in counties and on days where/when there was a greater number of new cases, and thus there was likely a higher perceived risk of infection,” the authors said. “Counties with a high rate of cases were likely to also have more restrictions in place.”
The researchers said that their findings support cell phone location monitoring to predict pandemic trends.
Aug 31 JAMA Intern Med study
Multicenter study suggests stealthy COVID-19 spread by children
Twenty of 91 children (22%) diagnosed as having COVID-19 in a South Korean study had no symptoms, and most symptoms in clinically ill children went unrecognized or developed only after diagnosis, suggesting that this age-group may silently spread coronavirus in the community.
The study, which involved pediatric contacts of people with COVID-19 at 22 medical centers from Feb 18 to Mar 31, was published late last week in JAMA Pediatrics. Of the 71 symptomatic children, 47 (66%) had symptoms that went unrecognized as coronavirus symptoms, and 18 (25%) developed symptoms only after diagnosis, while only 6 (9%) were diagnosed at the time of illness onset.
Of the 91 children, 22 (24%) had lower respiratory tract infections. RNA from SARS-CoV-2, the virus that causes COVID-19, was found in upper respiratory samples for a mean of 17.6 days among all patients and for a mean of 14.1 days in children with no symptoms. Mean duration of virus RNA detection was not different for children with upper versus lower respiratory tract infections (18.7 days vs 19.9 days). All patients recovered from their infections.
Median patient age was 11 years, 53 (58%) were boys, and 6 (7%) had underlying medical conditions. Fifty-seven children (63%) were infected by household members.
The authors called for heightened surveillance with COVID-19 testing to allow detection of the virus in children with no, mild, or nonspecific symptoms.
In a commentary in the same journal, Roberta DeBiasi, MD, MS, and Meghan Delaney, DO, MPH, of George Washington University pointed out that most ill children had symptoms for as long as 28 days before diagnosis, although they were presumably being monitored because they were a contact of a COVID-19 patient.
“This highlights the concept that infected children may be more likely to go unnoticed either with or without symptoms and continue on with their usual activities, which may contribute to viral circulation within their community,” they said.
Aug 28 JAMA Pediatr study and commentary
Ebola sickens 2 more in DRC outbreak, 109 total, with 47 deaths
Tests confirmed Ebola infections in 2 more people in the Democratic Republic of the Congo (DRC) Equateur province outbreak, raising the total to 109 cases, the World Health Organization (WHO) African regional office said today on Twitter.
No new deaths were reported, keeping the fatality count at 47.
The outbreak, the DRC’s 11th involving Ebola, was first detected in early June in the same area where the country’s ninth outbreak occurred in 2018.
Health officials are concerned about the latest outbreak, as responders grapple with COVID-19 and other health challenges and stretched resources. Also, the outbreak is occurring across a wide region, which includes both difficult-to-access areas and Mbandaka, the provincial capital.
Aug 31 WHO African regional office tweet