A 13-Year-Old Was the Source of COVID-19 at a 3-Week Family Gathering, 2020

By mid-2020 there was growing evidence that children and adolescents could spread SARS-CoV-2 efficiently. In July and August 2020, four state health departments and CDC investigated an outbreak at a three-week family gathering of five households, where the first — and suspected original — patient was a 13-year-old girl. Eleven more cases followed.

How it started

While away from home in June 2020, the girl was exposed during a large COVID-19 outbreak. Back home, she was tested: a rapid antigen test four days after the exposure, while she had no symptoms, was negative. Two days later she developed nasal congestion — her only symptom — and that same day she, her parents and her two brothers set off for a gathering with 15 other relatives, which began the next day.

The attendees came from five households in four states and ranged in age from 9 to 72.

• Fourteen relatives, including the girl, stayed in a five-bedroom, two-bathroom house for 8 to 25 days. They did not wear masks or keep their distance.
• Six more relatives — an aunt, an uncle and four cousins — visited for 10 hours on day 3 and 3 hours on day 10, when six of the overnight guests may have been infectious. They stayed outdoors and kept their distance, though no one wore masks.

Who got sick

Of the 14 people who shared the house, 12 developed COVID-19: six confirmed by PCR, four probable (by antigen test or clinical and epidemiologic criteria) and two suspected on the basis of antibody tests, including the girl. The girl and her two brothers, never tested while ill, all had antibodies 28 to 46 days after their symptoms began. Symptoms included fatigue, fever, chills, cough, loss of smell or taste, congestion, headache, shortness of breath, muscle aches, diarrhea, runny nose, sore throat and nausea. One person was hospitalized and another went to an emergency department; both recovered. The other two overnight guests never had symptoms, and one tested negative four days after the last exposure.

None of the six outdoor visitors got sick. Four tested negative by PCR four days after their last exposure; two were not tested.

COVID-19 cases among people at the three-week family gathering, June–July 2020. CDC, MMWR.

Eight relatives had done things outside the gathering that could have exposed them, but only the girl had contact with someone known to have COVID-19 or its symptoms. Her high-risk exposure, and her symptoms starting 3 to 19 days before anyone else's, support the conclusion that she was the source. Her negative antigen test was probably a false negative taken before symptoms began: the only antigen test authorized by the FDA at the time was meant for use in the first five days of symptoms.

Lessons

• Children and teens can start family outbreaks, even with mild symptoms.
• Distance helped. None of the relatives who kept their distance outdoors, even without masks, became ill.
• A negative rapid test isn't the last word. Rapid antigen tests are less sensitive than PCR (84.0%–97.6%); after a known exposure, a negative antigen result should be confirmed by PCR.
• Quarantine after exposure regardless of a negative test — 14 days under the guidance at the time — or after travel where authorities required it.
• Gatherings spread the virus, especially with long, close contact. Distancing, masks and hand hygiene reduce spread, and gatherings should be avoided where distancing and masks aren't possible.

Sources

• Schwartz NG, Moorman AC, Makaretz A, et al. "Adolescent with COVID-19 as the Source of an Outbreak at a 3-Week Family Gathering — Four States, June–July 2020." MMWR 69(40). CDC.