E-Paper
Delta variant 60% more transmissible than Alpha, reduces vaccine efficacy: UK Study
The Delta variant, which was upgraded from variant of interest to variant of concern by the World Health Organization, is said to be the reason behind the surge during the second wave of the pandemic.
The Delta variant of Covid-19 which was first detected in India is 60% more transmissible than the Alpha variant, which was first detected in United Kingdom’s Kent, Public Health England (PHE) said in a report on Friday.
“New research from PHE suggests that the Delta variant is associated with an approximately 60% increased risk of household transmission compared to the Alpha variant,” the UK health experts report stated.
The regional estimates for doubling rate of infection for the Delta is also relatively high, with doubling time ranging from 4.5 days to 11.5 days. Doubling rate is a concept borrowed from the world of finance, which simply means the time taken for the number of infections to double. The doubling rate of the Delta variant was around 3.4 days in India before states imposed lockdown, as per government estimates.
“Growth rates for Delta cases are high across the regions, with regional estimates for doubling time ranging from 4.5 days to 11.5 days,” PHE said in its analysis.
The Delta or B1.617.2 variant of concern (VOC) also reduces the efficacy of vaccines compared to its predecessor, with it being more pronounced in individuals who have just been inoculated with the first dose.
“There are now analyses from England and Scotland supporting a reduction in vaccine effectiveness for Delta compared to Alpha. This is more pronounced after one dose (absolute reduction in vaccine effectiveness against symptomatic infection of approximately 15% to 20% after one dose),” its risk assessment analysis reads.
Repeated analysis also demonstrated that vaccine effectiveness against the Delta variant is higher after both doses, but even then there’s slight reduction in the efficacy levels compared to the Alpha variant.
“Iterated analysis continues to show vaccine effectiveness against Delta is higher after two doses but that there is a reduction for Delta compared to Alpha,” the report states
“There is uncertainty around the magnitude of the change in vaccine effectiveness after two doses of Oxford-AstraZeneca vaccine,” it adds.
The report states that the maximum number of cases in the UK are of the delta variant but the increase in number of cases has not been accompanied by a corresponding increase in hospitalisations yet. It also advised vaccination as the best possible way to combat the infection when deployed in combination with following Covid-19 appropriate behaviour.
The Delta variant, which was upgraded from variant of interest to variant of concern by the World Health Organization, is said to be the reason behind the surge during the second wave of the pandemic. This study comes as the UK government is poised to announce if lockdown restrictions will be lifted all over the country by the end of June.
