Top 5 Takeaways

1. Limited Transmission: Despite the presence of multiple SARS-CoV-2 variants, there was no evidence of widespread transmission among the highly vaccinated attendees.
2. Preventive Measures: The implementation of vaccination requirements, consistent mask usage, and HEPA filtration likely contributed to the limited transmission.
3. Activity-Related Risks: Test-positive attendees were more likely to have engaged in activities such as attending bars, karaoke, or nightclubs, and eating or drinking indoors near others.
4. Survey and Testing: Surveillance and survey data from a portion of attendees indicated a 2.6% positivity rate, which was similar to the NYC average at the time.
5. Variant Identification: Genomic sequencing identified both Delta and Omicron variants among the cases, with no Delta variant cases forming part of a cluster.

Original Article Author and Citation

Corresponding Author

Libby Horter, qsw2@cdc.gov

Suggested Citation

Sami S, Horter L, Valencia D, et al. Investigation of SARS-CoV-2 Transmission Associated With a Large Indoor Convention — New York City, November–December 2021. MMWR Morb Mortal Wkly Rep 2022;71:243–248. DOI: http://dx.doi.org/10.15585/mmwr.mm7107a4

Summary

An investigation into SARS-CoV-2 transmission at a large indoor convention in New York City, attended by approximately 53,000 people, found no evidence of widespread transmission despite the presence of multiple variants. Preventive measures such as vaccination requirements, mask usage, and HEPA filtration were likely effective in limiting the spread of the virus.

Methods

The investigation used data from COVID-19 surveillance systems and an anonymous online survey. Surveillance data included test results, demographic data, and vaccination histories of attendees. The survey collected information on testing history, vaccination status, symptoms, and exposure data. Statistical analyses were performed to compare test-positive and test-negative respondents.

Discussion

The findings suggest that multiple preventive measures can effectively limit SARS-CoV-2 transmission at large indoor events. The limited transmission observed was likely due to the enforcement of vaccination and mask requirements, as well as the use of HEPA filtration. Activities such as attending bars and eating indoors were associated with higher transmission risk.

Conclusion

Implementing multiple preventive measures, including vaccination, mask usage, and improved ventilation, is crucial in limiting the transmission of highly transmissible SARS-CoV-2 variants during large indoor events. These measures can help maintain public health safety even in high-risk settings.

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