Delta variant of SARS-CoV-2: characteristics and implications for public health in Colombia

The SARS-CoV-2 Delta variant has become one of the greatest public health challenges worldwide since, after being first identified in India in December 2020, it has spread rapidly, affecting mainly countries with low vaccination rates and those that have relaxed the public health and social measures implemented to control the COVID-19 pandemic. The Delta variant has a higher replication capacity and is associated with viral loads up to 1 260 times higher than those of infections caused by the original strain, which may be associated with an increased likelihood of hospitalization, ICU admission, need for oxygen therapy, pneumonia, or even death. Fully vaccinated individuals have almost similar protection against both Delta and Alpha variants. Given the impact of Delta in countries where it is the dominant variant, it is necessary for all countries to develop systematic action plans focused on implementing strict public health and social measures in the context of the COVID-19 pandemic and on increasing vaccination coverage. Bearing this in mind, the objective of this reflection paper is to describe the main characteristics of the Delta variant, its impact on the dynamics of the pandemic in some of the countries where it has been detected, the effectiveness of vaccines against this variant, and its implications for public health in Colombia.