SARS-CoV-2 Lambda variant: spatiotemporal distribution and potential public health impact

ABSTRACT

Various SARS-CoV-2 variants have continually emerged since the summer of 2020. Recently, the spread and potential effects of the Lambda variant on public health have caused great scientific and public concern. The Lambda variant (C.37), first identified in Peru in December 2020, contains a novel deletion (?246-252) and two novel mutations, L452Q and F490S, not present in the ancestral strain and other variants. The Lambda variant was designated a variant of interest in April of 2021. By the end of July, this variant sequence was detected in more than 30 countries worldwide, mostly in South America. This study analyzed the global spatiotemporal distribution of the Lambda variant from the beginning of January to the end of July from publicly available data. The Lambda variant spread rapidly in Peru and became predominant in March. Circulation of the Lambda variant has also been observed in some neighboring countries, i.e., Argentina, Chile and Ecuador, where it has remained at remarkably low levels. The circulation of the Lambda variant in other countries in South America (e.g., Brazil and Colombia) and other regions of the world has also occurred at very low levels, even though this variant has been known for a long time. Multivariate linear regression analyses of the proportion of case fatalities attributable to the Lambda variant, the new deaths and the new confirmed cases per million (7-day rolling average) in Peru did not show significant associations. A review of the most recent data on the Lambda variant has suggested this variant's relatively high infectivity in cultured cells and low neutralizing titers of convalescent sera and vaccine-elicited antibodies in vitro. However, the exact effects of this variant on clinical severity and vaccine effectiveness remain poorly documented. The currently authorized COVID-19 vaccines are still believed to provide efficient protection against the Lambda variant.