CDC: NYC anime convention was not a superspreader event

A 53,000-person anime convention in New York City in late November was not an omicron superspreader event, a Centers for Disease Control and Prevention (CDC) investigation found.

Indoor mask wearing, a vaccine requirement, booster shots and a high-quality air filtration system in the Javits Center largely helped prevent the virus’s transmission, the CDC said.

Among 4,560 attendees with available test results, just 119 tested positive for COVID-19, a rate of only 2.6 percent. 

“These findings reinforce the importance of implementing multiple, simultaneous prevention measures, such as ensuring up-to-date vaccination, mask use, physical distancing, and improved ventilation in limiting SARS-CoV-2 transmission, during large, indoor events,” the CDC said.

The anime convention attracted tens of thousands of people from 52 U.S. jurisdictions and 30 countries from Nov. 19 to 21. The convention required attendees to have received at least one dose of a COVID-19 vaccine and enforced mask-wearing while attendees were indoors.

More than 4,000 survey respondents reported always wearing a mask while indoors at the event, and “compared with test-negative respondents, test-positive respondents were more likely to report attending bars, karaoke, or nightclubs, and eating or drinking indoors near others for at least 15 minutes.”

Among the people who tested positive, nasal congestion or runny nose and fatigue were the most common symptoms reported. 

A second, parallel CDC investigation of a group of 23 friends who attended the convention found that 16 of them received a positive test result. Four of them stayed in the same vacation house, while all participated in mostly unmasked visits to restaurants, bars, clubs, and karaoke venues.

All 23 attendees had received a primary COVID-19 vaccination series, and 11 had received a booster. Their median age was 24. 

“Potential contributing factors to the high attack rates include unmasked and prolonged contact in social settings and residential accommodations,” the CDC said. “This finding among this group contrasts with the observed overall transmission at the convention, which was relatively low.”

There was limited convention-associated transmission identified outside of this cluster, the CDC found, and all omicron cases were associated with this group. 

“Patient A” in the group was a man from Minnesota who flew to the convention on Nov. 18, the day before it began. He later became the first reported case of community-acquired omicron infection in the country.

Once they returned home, the 16 attendees with positive test results infected 33 percent of their household contacts, including four who had received a booster dose less than 14 days before exposure.

“The high attack rates among fully vaccinated persons illustrate omicron variant’s partial escape from vaccine-induced immunity,” the CDC said. “However, illness was relatively mild among this cohort, consistent with evidence that vaccinated persons with infections are less likely to experience serious illness.”

Similar to other studies, the agency said fewer people who received a booster dose tested positive — six of 11 — compared with those who had not received a booster dose, at 10 of 12.