Lambda and Epsilon: The latest Covid variants

With concerns mounting over the emergence and spread of Covid variants, we take a closer look at two strains recently flagged by the World Health Organization: Lambda and Epsilon. 

Lambda has been designated a variant of interest, the most recent strain to be added to the category. It first appeared last year in Peru, where it now accounts for 82 per cent of new Covid-19 cases. There are seven mutations in its spike protein, the shaped casing of the virus that interacts with the host body’s cells, that officials are concerned may increase transmissibility or make the virus more resistant to particular antibodies. Some researchers and a preliminary study have indicated that one mutation in particular, labelled F490S, could allow the strain to bypass the defences built up by current vaccines. But another study currently undergoing peer review suggests that the mRNA vaccines, namely Pfizer and Moderna, are effective against the Lambda variant. Research is ongoing.

The Epsilon strain has been relabelled from variant of interest to variant of concern by the World Health Organization. It was first reported in California in May last year, and has now spread to at least 35 countries. Three mutations in its spike protein decrease the neutralizing abilities of antibodies induced by past Covid-19 infections or vaccines, a study found. The Pfizer and Moderna mRNA vaccines have been found to be 2-3.5 times less potent against the Epsilon strain than others.

A failure to reduce transmission of new variants, however, is not necessarily a failure to reduce severe illness and deaths. Using the example of the Delta variant, where we have more data, Pfizer has 64 per cent effectiveness in preventing spread, but 90 per cent in preventing severe illnesses or hospitalization. 

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