A coronavirus outbreak infecting 11 family members, stemming from a 13-year-old girl, recently prompted an investigation by several state health departments and the Centers for Disease Control and Prevention.
The teen was away from home in June when she was exposed to a large coronavirus outbreak. While she was asymptomatic, a rapid antigen test conducted four days after exposure came back negative, per a new CDC report.
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A couple of days later, shortly before accompanying her siblings and parents on a large family vacation, the only symptom the young girl developed was nasal congestion.
A total of 14 relatives, ages ranging from 9 to 72, stayed together for up to three weeks in a five-bedroom house, ignoring masks and social distancing. The CDC says 12 of the 14 family members developed symptoms and had either probable, suspected, or confirmed COVID-19 cases. One person was hospitalized while another sought emergency care for respiratory symptoms, though both recovered.
Another six family members visited the house, but stayed outdoors; four later tested negative and two were not tested.
The 13-year-old girl (or “index patient;" the believed source of infection) later tested positive for COVID-19 antibodies.
The CDC theorized her rapid antigen test returned a false-negative result because it was done before she developed symptoms, adding “the only antigen test that had Food and Drug Administration Emergency Use Authorization at the time was intended for use within the first 5 days of symptoms.”
The CDC says to confirm coronavirus test results with a nasal swab test, RT-PCR given its higher sensitivity and therefore accuracy. (iStock)
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The event emphasizes multiple issues, the CDC wrote.
"Children and adolescents can serve as the source for COVID-19 outbreaks within families, even when their symptoms are mild," the CDC said. Additionally, the outbreak offers further evidence for “physical distancing as a mitigation strategy to prevent SARS-CoV-2 transmission.”
Third, since rapid antigen tests are generally less sensitive than nasal swabs/RT-PCR testing, the CDC advises confirming negative rapid results with a swab test. The agency called for 14-day self-quarantine following exposure or travel, even if virus tests return negative.
"Finally, SARS-CoV-2 can spread efficiently during gatherings, especially with prolonged, close contact," the CDC wrote. (On Monday the agency updated its recommendations to acknowledge the potential for infection from airborne transmission, especially in enclosed places with poor ventilation.)
To prevent infection, the CDC advises physical distancing, mask usage, adequate hand hygiene, and avoiding gatherings where physical distancing and mask use aren’t possible.