How many children have asymptomatic coronavirus infections? New data released

A new study suggests that the prevalence of children with asymptomatic SARS-CoV-2 infection is relatively low in many parts of the United States. But the numbers are high enough that school closures may result, if children are as contagious as some recent studies imply.

As schools and other institutions reopen in the United States, one of the many debates has been centered on whether, similar to influenza, children will serve as spreaders of covid-19, thereby exposing their fellow classmates and more importantly at-risk adult teachers. Aggressive screening methods may hopefully identify children who are ill without the need for universal testing, but what about those with asymptomatic infections who are still capable of spreading covid-19? A research letter published today in JAMA Pediatrics looked to add additional information that might be helpful to officials tasked with making decisions on whether schools should reopen and if and when closures should occur in the coming weeks and months. 

Smaller previous focused studies assessed specific groups of children, such as those undergoing emergency surgery or cancer-related care. But those groups lacked the data to make broad conclusions that would be applicable to most children. 

That led researchers from University of California-San Francisco to take data from 28 children's hospitals across the United States. Testing data was obtained during routine screening of children receiving elective medical and surgical care up until May 29, 2020. Of the 33,041 asymptomatic children tested across these facilities, only 250 were found to be positive for SARS-CoV-2. Asymptomatic prevalence of coronavirus infections in children across the 28 hospitals varied from 0 percent to 2.2 percent. The only factor which was associated with pediatric asymptomatic prevalence was the weekly incidence of covid-19 among the general population during a 6-week period where most of the testing occurred. 

Overall, the most important result from this study is that researchers found a rather low "pooled prevalence" (0.65 percent) of positive tests among asymptomatic children being treated for medical or surgical care. Given the association found between weekly covid-19 cases in the communities studied and asymptomatic prevalence among children, these findings might be useful in helping to guide community policy.

What is unclear is whether a small number of infected children might contribute to a large number of infections. So-called "superspreaders" could portend a very short school year.


A Note From Brief19

A high percentage of United States residents continue to rely on employer-based health insurance plans. The covid-19 crisis has unmasked the boom-or-bust nature of this approach. We asked the author of a Perspective published in The New England Journal of Medicine to share expertise with our readers.

New options created by ACA protect the newly unemployed from losing health insurance

The United States Supreme Court announced that it will again hear oral arguments on the constitutionality of the Affordable Care Act (ACA, or "Obamacare") on November 10, one week after Election Day. The newest challenge to the ACA is led by a contingent of 18 Republican state attorneys-general and is supported by the Trump administration.

However, amid the covid-19 pandemic that has led to widespread layoffs (and possibly permanent job losses), the uniquely American system in which a high number of people get their health insurance through their employers now threatens to cut millions of people off from their insurance plans. In that context, it is important to recognize the new options created by the ACA for health insurance that are unrelated to employment. These include more generous Medicaid eligibility criteria in the 36 states that chose to expand their programs, extension of dependent coverage to 26 years of age, and insurance marketplaces supported by consumer protections and premium tax credits. 

  In a recent article in the New England Journal of Medicine, my colleague Benjamin Sommers and I quantified the ACA's effect on changes in health insurance coverage after job losses. We used national data from the Medical Expenditure Panel Survey. We compared the trajectories in coverage for nonelderly adults who lost their jobs before 2014—the year the law's Medicaid and marketplace provisions went into full effect—with the trajectories of those who lost their jobs after 2014. As expected, there were large drops in employer-sponsored insurance after job losses (more than 12 percent), whether a job loss occurred before or after 2014. However, after implementation of the ACA, there were large gains in Medicaid (8.9 percent) and marketplace coverage (2.6 percent) that fully offset the reduction in employer-sponsored insurance for people who left or lost their jobs. These results suggest that the ACA will play a critical role in alleviating coverage losses related to the covid-19 recession.   

  In the context of millions of Americans losing their jobs in a short period of time, and an ongoing pandemic, overturning the ACA would likely be devastating to patients, clinicians, hospitals, and state economies. The very virus that has brought about record unemployment levels is the same agent that makes health insurance—and the new options created under the ACA—more important than ever. 

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