Background: Nagaland reported 12,233 COVID-19 cases from May 25, 2020–March 29, 2021 (6,128 cases per million). On March 30, 2021, a cluster of COVID-19 cases was reported from a private residential training institute in Phesama village, Kohima, Nagaland, following the reopening of the training session in February 2021. We investigated to describe the epidemiology of the outbreak and provide evidence-based recommendations.
Methods: We defined a case as SARS-CoV-2 positive reverse transcriptase-polymerase chain reaction (RT-PCR) or rapid antigen test (RAT) among residents of the training institute in Phesama from March 13–April 7, 2021. We interviewed the cases using a semi-structured questionnaire for demographics, clinical presentation, underlying comorbidities, recent travel history, contact history, and COVID-19 appropriate behavior. We calculated frequency, proportion, median age, and attack rate (AR). Nasopharyngeal swab samples were sent for genome sequencing.
Results: We identified 114 COVID-19 cases (111 by RT-PCR and 2 by RAT) among the 115 residents of the training institute (AR=99%). The median age was 24 years (range: 1–78 years), 107 (95%) in the age group of 16–35 years, 98 (86%) were trainees, 92 (81%) were female, and 27 (24%) were symptomatic. None of the cases were hospitalized, required oxygen support, or had comorbidities. A total of 25 (22%) cases had traveled from other states in India in the last 2 months, 1/25 (4%) had negative COVID-19 report 72 hours prior to arrival, none were tested on arrival. All 25 followed 14 days of mandatory quarantine at the institute and were asymptomatic throughout the period. A total of 4 of the 5 samples showed B.1.617.1 strain (Kappa variant).
Conclusions: We report a confirmed COVID-19 outbreak predominantly among trainees in a residential training institute. We recommended entry and exit restriction, contact tracing, testing, daily monitoring of cases for symptoms at the training institute for 2 weeks, and ensuring testing on arrival for those with no negative report.