COVID-19 Vaccines Still Effective Against The Delta Plus Variant, Study Says

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The emergence of new COVID variants that might undermine the immunity garnered from vaccines and threaten the halt of the spread of the infection is concerning, however, a new study has found that the Delta+ variant is no more dangerous than the Delta variant, and that current vaccines confer protection against both.

The newly discovered mutation of the Delta variant, formally called AY.4.2 but known as Delta+, is currently being investigated in the UK, though is not yet a "variant of concern". The UK is experiencing an increase in COVID-19 cases, with Public Health England reporting that the Delta+ sublineage now accounts for 6-8 percent of all COVID-19 cases in the UK. It's not yet known if the new variant is more transmissible, but the rise in cases is likely a consequence of the UK removing all public health measures to reduce spread (compulsory wearing masks indoor, social distancing rules, vaccine passports) and stagnating vaccination rates providing fertile ground for the evolution of new variants.

Yesterday, the CDC director Rochelle Walensky confirmed the new variant has been identified in the US, though not with an increasing frequency or cluster. Israel has also confirmed cases. 

Fortunately, it seems that both Delta+ and regular Delta are still being fought off well by current vaccines. While not as effective as they were against the original strain of SARS-CoV-2 – the virus that causes COVID-19 – the vaccines are able to elicit a strong immune response against these two versions of the Delta variants as well as other sublineages, according to findings published in Cellular and Molecular Immunology.

"This means that vaccination likely confers comparable protection against Delta and Delta Plus, and that Delta Plus is not significantly more dangerous than Delta," co-author Professor Stefan Pöhlmann, from the Leibniz Institute for Primate Research, said in a statement.

The team has conducted multiple studies on the variant and its new versions. In a second paper, published in Cell Reports, they describe how and why the Delta variant is better at infecting us. It appears that the Delta variant is much better at entering lung cells than the original version of the virus, which gives it some concerning advantages.

"It is conceivable that by fusing cells in the respiratory tract, the Delta variant may spread more efficiently and induce more damage. This could contribute to a more severe course of COVID-19," said lead author Dr Prerna Arora.

The team also found heterologous vaccination, where people received one dose of the Oxford/AstraZeneca vaccine and then a second dose of the Pfizer/BioNTech, seemed to elicit a stronger immune response than two doses of the AstraZeneca jab and had significantly more antibodies that inhibited the Delta variant. 

"Our studies show that heterologous vaccination induces significantly more neutralizing antibodies to Delta than two vaccination shots with Oxford-AstraZeneca. Individuals who have received such a heterologous vaccination may have a very good immune protection against Delta and Delta Plus," explained co-author of the third study Markus Hoffmann.

This scenario has been common in Europe, where some rare side-effects stopped the administration of the AstraZeneca vaccine for a while.  A recent study in The Lancet also backed this mix 'n' match approach to dealing with the Delta variant.  


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