Testing people who had COVID-19 with no symptoms or mild symptoms could help us contain the coronavirus.
Containing SARS-CoV-2—the novel coronavirus that causes COVID-19—will involve many complex challenges, writes NIH Director Dr. Francis Collins in a recent blog. The biggest challenge will be to figure out ways to use testing technology to identity 2 sets of people.
First, we’ll need to identify Infected individuals who have no symptoms but are still capable of transmitting the virus.
Researchers estimate that 44% of SARS-CoV-2 transmissions occur before people get sick. This makes it challenging to contain the virus using traditional containment strategies, such as testing only people with symptoms, contact tracing, and quarantine.
A new study, published in Nature Medicine, estimates that if more than 30% of new infections come from people who are asymptomatic, and those people aren’t tested and found positive until 2 or 3 days later, public health officials will need to track down more than 90% of their close contacts and get them quarantined quickly to contain the virus. As an alternative, NIH is exploring ways to carry out digital tracing while protecting personal privacy.
Second, we’ll need to find infected individuals who didn’t get seriously ill and can no longer transmit the virus to others.
Because these individuals may be protected against future infections, they may be able to care for people with COVID-19 or for people who are vulnerable to the infection, writes Collins.
Early results from an ongoing study of residents in Los Angeles County showed that approximately 4.1% tested positive for antibodies against SARS-CoV-2. But Collins warns that antibody tests “are just in the development stage.”
“It’s possible some of these results might represent false positives—perhaps caused by antibodies to some other less serious coronavirus that’s been in the human population for a while,” he writes.
The NIH’s National Institute of Allergy and Infectious Diseases recently launched a study to help gauge how many adults in the U. S. with no confirmed history of a SARS-CoV-2 infection have antibodies to the virus. Researchers will collect and analyze blood samples from 10,000 volunteers to get a better picture of SARS-CoV-2’s prevalence and potential to spread within the country.