Latin America and the Caribbean: Updated Surveillance Metrics and History of the COVID-19 Pandemic (2020-2023).

BACKGROUND:This study updates the COVID-19 surveillance in Latin America and the Caribbean we first conducted in 2020 with two additional years of data for the region. OBJECTIVE:First, we measure whether there pandemic was expanding or contracting in Latin America and the Caribbean when the World Health Organization (WHO) declared the end of COVID-19 as a public health emergency of international concern on May 5, 2023. Second, we use dynamic and genomic surveillance methods to describe the history of the pandemic in the region and situate the window of the WHO declaration within the broader history. Third, with a focus on prevention policies, we provide historical context for the course of the pandemic in the region. METHODS:In addition to updates of traditional surveillance data and dynamic panel estimates from the original study Post et al. (2021), this study used data on sequenced SARS-CoV-2 variants from the Global Initiative on Sharing All Influenza Data (GISAID) to identify the appearance and duration of variants of concern. We used Nextclade nomenclature to collect clade designations from sequences and Pangolin nomenclature for lineage designations of SARS-CoV-2. Additionally, we conducted a one-sided t-test for whether regional weekly speed was greater than an outbreak threshold of ten. We ran the test iteratively with six months of data across the period from August 2020 to May 2023. RESULTS:Speed, or the rate of novel COVID-19 transmissions, for the region had remained below the outbreak threshold for six months by the time of the WHO declaration. Acceleration and jerk were also low and stable. While the 1- and 7-day persistence coefficients remained statistically significant for the 120-day period ending on the week of May 5, 2023, the coefficients were relatively modest in magnitude (0.457 and 0.491, respectively). Furthermore, the shift parameters for either of the two most recent weeks around May 5, 2023, did not indicate any change in this clustering effect of cases on future cases. From December of 2021 onward, Omicron was the predominant variant of concern in sequenced viral samples. The rolling t-test of speed equal to ten became entirely insignificant from January 2023 onward. CONCLUSIONS:While COVID-19 continues to circulate in Latin America and the Caribbean, the rate of transmission had remained well below the threshold of an outbreak for six months ahead of the WHO declaration. Surveillance data suggest COVID-19 is endemic in the region and no longer reaches the threshold of the pandemic definition. However, the region experienced a high COVID-19 disease burden in the early stages of the pandemic, and prevention policies should be an immediate focus in future pandemics. Ahead of vaccination development, these policies can include widespread testing of individuals and an epidemiological task force with a contact-tracing system. CLINICALTRIAL: