Delta variant is now the second most prevalent variant of concern (VoC) globally

Posted on Jun 23, 2021

Now detected in 65 countries, the Delta variant has become the second most prevalent VoC globally. Reported to be up to 60% more transmissible than other variants, research is underway to identify the effectiveness COVID-19 vaccines currently being used around the world.

A Scottish real world study investigating vaccine efficacy against RT-PCR positive infections found that Pfizer offered strong protection against the Delta variant with effectiveness of 79%, versus 92% against other variants. AstraZeneca showed a similar but more significant reduction of 60%, versus 73% against non-Delta variants. This study and a preprint supports vaccine effectiveness against hospitalisation by the Delta variant, and the latter actually shows slightly higher vaccine effectiveness at 94% compared with the Alpha variant at 92%. 

The top reported symptoms linked to COVID-19 also appear to be shifting. Researchers analysing data from the Zoe COVID-19 tracking app have found that the top three symptoms being reported since the beginning of May are a headache, sore throat and a runny nose. A cough was more rarely reported and loss of taste and smell are not commonly reported with new cases. 

Given the increased transmissibility, new information may need to be circulated to ensure those with these new symptoms are isolating and getting tested.

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