Outbreak of SARS-CoV-2 Infections, Including COVID-19 Vaccine Breakthrough Infections, Associated with Large Public Gatherings — Barnstable County, Massachusetts, July 2021 Catherine M. Brown, DVM1; Johanna Vostok, MPH1; Hillary Johnson, MHS1; Meagan Burns, MPH1; Radhika Gharpure, DVM2; Samira Sami, DrPH2; Rebecca T. Sabo, MPH2; Noemi Hall, PhD2; Anne Foreman, PhD2; Petra L. Schubert, MPH1; Glen R. Gallagher PhD1; Timelia Fink1; Lawrence C. Madoff, MD1; Stacey B. Gabriel, PhD3; Bronwyn MacInnis, PhD3; Daniel J. Park, PhD3; Katherine J. Siddle, PhD3; Vaira Harik, MS4; Deirdre Arvidson, MSN4; Taylor Brock-Fisher, MSc5; Molly Dunn, DVM5; Amanda Kearns5; A. Scott Laney, PhD2 On July 30, 2021, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr). During July 2021, 469 cases of COVID-19 associated with multiple summer events and large public gatherings in a town in Barnstable County, Massachusetts, were identified among Massachusetts residents; vaccination coverage among eligible Massachusetts residents was 69%. Approximately three quarters (346; 74%) of cases occurred in fully vaccinated persons (those who had completed a 2-dose course of mRNA vaccine [Pfizer-BioNTech or Moderna] or had received a single dose of Janssen [Johnson & Johnson] vaccine ≥14 days before exposure). Genomic sequencing of specimens from 133 patients identified the B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, in 119 (89%) and the Delta AY.3 sublineage in one (1%). Overall, 274 (79%) vaccinated patients with breakthrough infection were symptomatic. Among five COVID-19 patients who were hospitalized, four were fully vaccinated; no deaths were reported. Real-time reverse transcription–polymerase chain reaction (RT-PCR) cycle threshold (Ct) values in specimens from 127 vaccinated persons with breakthrough cases were similar to those from 84 persons who were unvaccinated, not fully vaccinated, or whose vaccination status was unknown (median  =  22.77 and 21.54, respectively). The Delta variant of SARS-CoV-2 is highly transmissible (1); vaccination is the most important strategy to prevent severe illness and death. On July 27, CDC recommended that all persons, including those who are fully vaccinated, should wear masks in indoor public settings in areas where COVID-19 transmission is high or substantial.* Findings from this investigation suggest that even jurisdictions without substantial or high COVID-19 transmission might consider expanding prevention strategies, including masking in indoor public settings regardless of vaccination status, given the potential risk of infection during attendance at large public gatherings that include travelers from many areas with differing levels of transmission. During July 3–17, 2021, multiple summer events and large public gatherings were held in a town in Barnstable County,

Wabah Infeksi SARS-CoV-2, Termasuk Infeksi Terobosan Vaksin COVID-19, Terkait dengan Pertemuan Publik Besar — ​​Barnstable County, Massachusetts, Juli 2021 Catherine M. Brown, DVM1; Johanna Vostok, MPH1; Hillary Johnson, MHS1; Luka Bakar Meagan, MPH1; Radhika Gharpure, DVM2; Samira Sami, DrPH2; Rebecca T. Sabo, MPH2; Noemi Hall, PhD2; Anne Foreman, PhD2; Petra L. Schubert, MPH1; Glen R. Gallagher PhD1; Timelia Fink1; Lawrence C. Madoff, MD1; Stacey B. Gabriel, PhD3; Bronwyn MacInnis, PhD3; Daniel J. Park, PhD3; Katherine J. Siddle, PhD3; Vaira Harik, MS4; Deirdre Arvidson, MSN4; Taylor Brock-Fisher, MSc5; Molly Dunn, DVM5; Amanda Kearns5; A. Scott Laney, PhD2 Pada tanggal 30 Juli 2021, laporan ini diposting sebagai Rilis Awal MMWR di situs web MMWR (https://www.cdc.gov/mmwr). Selama Juli 2021, 469 kasus COVID-19 yang terkait dengan beberapa acara musim panas dan pertemuan publik besar di sebuah kota di Barnstable County, Massachusetts, diidentifikasi di antara penduduk Massachusetts; cakupan vaksinasi di antara penduduk Massachusetts yang memenuhi syarat adalah 69%.Sekitar tiga perempat (346; 74%) kasus terjadi pada orang yang divaksinasi lengkap (mereka yang telah menyelesaikan 2 dosis vaksin mRNA [Pfizer-BioNTech atau Moderna] atau telah menerima dosis tunggal vaksin Janssen [Johnson & Johnson] 14 hari sebelum paparan). Pengurutan genom spesimen dari 133 pasien mengidentifikasi varian B.1.617.2 (Delta) dari SARS-CoV-2, virus yang menyebabkan COVID-19, pada 119 (89%) dan sublineage Delta AY.3 dalam satu (1 %). Secara keseluruhan, 274 (79%) pasien yang divaksinasi dengan infeksi terobosan menunjukkan gejala. Di antara lima pasien COVID-19 yang dirawat di rumah sakit, empat divaksinasi lengkap; tidak ada kematian yang dilaporkan. Nilai ambang batas siklus (Ct) transkripsi balik real-time-polymerase chain reaction (RT-PCR) dalam spesimen dari 127 orang yang divaksinasi dengan kasus terobosan serupa dengan 84 orang yang tidak divaksinasi, tidak divaksinasi sepenuhnya, atau yang status vaksinasinya tidak diketahui (median  =  22,77 dan 21,54, masing-masing). Varian Delta dari SARS-CoV-2 sangat menular (1); vaksinasi adalah strategi paling penting untuk mencegah penyakit parah dan kematian.Pada 27 Juli, CDC merekomendasikan agar semua orang, termasuk mereka yang divaksinasi lengkap, harus mengenakan masker di tempat umum dalam ruangan di area di mana penularan COVID-19 tinggi atau substansial.* Temuan dari penyelidikan ini menunjukkan bahwa bahkan yurisdiksi tanpa COVID-19 substansial atau tinggi Penularan -19 mungkin mempertimbangkan perluasan strategi pencegahan, termasuk penggunaan masker di tempat umum dalam ruangan terlepas dari status vaksinasi, mengingat potensi risiko infeksi selama menghadiri pertemuan publik besar yang mencakup pelancong dari banyak daerah dengan tingkat penularan yang berbeda. Selama 3–17 Juli 2021, beberapa acara musim panas dan pertemuan publik besar diadakan di sebuah kota di Barnstable County,