Volume 28, Number 1—January 2022
Synopsis
Multistate Outbreak of SARS-CoV-2 Infections, Including Vaccine Breakthrough Infections, Associated with Large Public Gatherings, United States
Figure 2
![Figure 2. Transmission diagram of primary (n = 26) and secondary (n = 30) cluster-associated cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, by vaccination status and date of symptom onset or specimen collection, after large public gatherings in Provincetown, Massachusetts, USA, July 2021. A primary case was defined as detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person <14 days after travel to or residence in Provincetown during July 3–17. A secondary case was defined as detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person <14 days after close contact (within 6 feet for a cumulative total of >15 minutes within a 24-hour period) with a person who had a primary case during their infectious period, and without history of travel to or residence in Provincetown during July 3–August 10. The infectious period of a person with a primary case was defined as 2 days before through 10 days after symptom onset or, if asymptomatic, 2 days before or through 10 days after a positive test result. A vaccine breakthrough case was a cluster-associated case in a person who completed all recommended doses of a US Food and Drug Administration‒authorized COVID-19 vaccine (2 doses of Pfizer/BioNTech [https://www.pfizer.com] or Moderna [https://www.modernatx.com], or 1 dose of Johnson & Johnson [https://www.jandj.com]) >14 days before collection of a SARS-CoV-2‒positive specimen. Gray shading indicates the event exposure period (July 3–17, 2021) in the primary case definition. Only primary cases associated with a secondary case are shown. Symptom onset of persons with secondary cases before symptom onset of persons with primary cases was observed in 4 pairs, consistent with previous reports (21,22), and could be caused by presymptomatic transmission (23,24) or variability in self-reported symptom onset date. Household contacts were exposed to persons who had a primary case within household settings. Settings of nonhousehold exposures were workplace (1), summer camp (2), social gatherings (4), shared ride (1), and unknown (1). Transmission diagram of primary (n = 26) and secondary (n = 30) cluster-associated cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, by vaccination status and date of symptom onset or specimen collection, after large public gatherings in Provincetown, Massachusetts, USA, July 2021. A primary case was defined as detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person <14 days after travel to or residence in Provincetown during July 3–17. A secondary case was defined as detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person <14 days after close contact (within 6 feet for a cumulative total of >15 minutes within a 24-hour period) with a person who had a primary case during their infectious period, and without history of travel to or residence in Provincetown during July 3–August 10. The infectious period of a person with a primary case was defined as 2 days before through 10 days after symptom onset or, if asymptomatic, 2 days before or through 10 days after a positive test result. A vaccine breakthrough case was a cluster-associated case in a person who completed all recommended doses of a US Food and Drug Administration‒authorized COVID-19 vaccine (2 doses of Pfizer/BioNTech [https://www.pfizer.com] or Moderna [https://www.modernatx.com], or 1 dose of Johnson & Johnson [https://www.jandj.com]) >14 days before collection of a SARS-CoV-2‒positive specimen. Gray shading indicates the event exposure period (July 3–17, 2021) in the primary case definition. Only primary cases associated with a secondary case are shown. Symptom onset of persons with secondary cases before symptom onset of persons with primary cases was observed in 4 pairs, consistent with previous reports (21,22), and could be caused by presymptomatic transmission (23,24) or variability in self-reported symptom onset date. Household contacts were exposed to persons who had a primary case within household settings. Settings of nonhousehold exposures were workplace (1), summer camp (2), social gatherings (4), shared ride (1), and unknown (1).](/eid/images/21-2220-F2.jpg)
Figure 2. Transmission diagram of primary (n = 26) and secondary (n = 30) cluster-associated cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, by vaccination status and date of symptom onset or specimen collection, after large public gatherings in Provincetown, Massachusetts, USA, July 2021. A primary case was defined as detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person <14 days after travel to or residence in Provincetown during July 3–17. A secondary case was defined as detection of SARS-CoV-2 RNA or antigen in a respiratory specimen collected from a person <14 days after close contact (within 6 feet for a cumulative total of >15 minutes within a 24-hour period) with a person who had a primary case during their infectious period, and without history of travel to or residence in Provincetown during July 3–August 10. The infectious period of a person with a primary case was defined as 2 days before through 10 days after symptom onset or, if asymptomatic, 2 days before or through 10 days after a positive test result. A vaccine breakthrough case was a cluster-associated case in a person who completed all recommended doses of a US Food and Drug Administration‒authorized COVID-19 vaccine (2 doses of Pfizer/BioNTech [https://www.pfizer.com] or Moderna [https://www.modernatx.com], or 1 dose of Johnson & Johnson [https://www.jandj.com]) >14 days before collection of a SARS-CoV-2‒positive specimen. Gray shading indicates the event exposure period (July 3–17, 2021) in the primary case definition. Only primary cases associated with a secondary case are shown. Symptom onset of persons with secondary cases before symptom onset of persons with primary cases was observed in 4 pairs, consistent with previous reports (21,22), and could be caused by presymptomatic transmission (23,24) or variability in self-reported symptom onset date. Household contacts were exposed to persons who had a primary case within household settings. Settings of nonhousehold exposures were workplace (1), summer camp (2), social gatherings (4), shared ride (1), and unknown (1).
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1These authors contributed equally to this article.
2These senior authors contributed equally to this article.