The WHO has said recently that the prevalence of the highly transmissible Delta variant of COVID-19 among specimens sequenced over the past four weeks crossed 75 per cent in many countries worldwide, including India, China, Russia, Israel, and the UK.
The World Health Organisation in the COVID-19 Weekly Epidemiological Update published July 20 said, that many countries across all six WHO regions continue to experience an increase in coronavirus cases, despite of efforts to extend vaccination coverage.
A total of over 2.4 million SARS-CoV-2 sequences have been submitted to GISAID, the global science initiative and primary source that provides open access to genomic data noted the update as of July 20. Over 220,000 (9 per cent) of SARS-CoV-2 sequences submitted to GISAID are confirmed as the Delta variant.
Over the past week, the highest numbers of new cases were reported from Indonesia (350,273 new cases; a 44 per cent increase), the UK (296,447 new cases; 41 per cent increase), Brazil (287,610 new cases; 14 per cent decrease), India (268,843 new cases; 8 per cent decrease) and the US (216,433 new cases; 68 per cent increase).
“According to GISAID data, as of 20 July, the prevalence of Delta among the specimens sequenced over the past 4 weeks exceeded 75 per cent in many countries worldwide including Australia, Bangladesh, Botswana, China, Denmark, India, Indonesia, Israel, Portugal, Russian Federation, Singapore South Africa and the United Kingdom,” the update said.
It reiterated that the Delta variant is expected to “rapidly outcompete” other variants and become the dominant circulating lineage over the coming months.
Cases of the Alpha variant have been reported in 180 countries territories or areas globally. While the Beta variant has been reported in 180 countries 78 countries cases of the Gamma variant and 124 countries have reported cases of the Delta variant.
There are growing signals that supports the increased transmissibility of the Delta variant in comparison to non-Variants of Concern (VOCs) but the exact mechanism for the increase in transmissibility still remains uncertain, said the update.
The update cited a recent study from China during an outbreak of the Delta variant that examined the time interval from the exposure of a quarantined population to the first positive Polymerase Chain Reaction (PCR) result and found that the interval may be shorter for the Delta variant when compared to non-VOCs.
“Moreover, the viral load of the first positive test of Delta infection was over 1,200 times higher than non-VOCs, suggesting that this VOC may be able to replicate faster and be more infectious during the early stages of infection.”
Another study from Canada analysing data from over 200,000 COVID-19 cases showed an increase in virulence of the Delta variant when compared to non-VOCs. The risk of hospitalisation, among the COVID-19 cases ICU admission and death associated with the Delta variant compared to non-VOCs raised by 120 per cent, 287 per cent and 137 per cent respectively.
The update said that the global number of new cases reported for the July 12-18 week was over 3.4 million, a 12 per cent increase as compared to the previous week.
Globally, the weekly incidence of COVID-19 cases increased with an average of around 490,000 cases reported each day over the past week as compared to 400,000 cases reported daily in the previous week. As compared to the previous week the South-East Asia region reported over 829,000 new cases and over 16,000 new deaths, increases of 16 per cent and 12 per cent.
“Weekly case incidence and mortality in India and Sri Lanka continue to decline, with the regional trends being driven mainly by marked increases in Indonesia, Thailand and Myanmar,” the update said.
In the region, the highest numbers of new cases were reported from Indonesia (350,273 cases; 128.1 cases/100,000; +44 per cent), India (268,843 cases; 19.5 cases/100,000; -8 per cent) and Bangladesh (82,800 cases; 50.3 cases/100,000; +9 per cent).
The highest numbers of new deaths were reported from Indonesia (7,118 deaths; 2.6 deaths/ 100,000; +21 per cent), India (5,569 deaths; 0.4 deaths/100,000; -8 per cent) and Bangladesh (1,475 deaths; 0.9 deaths/100 000; +9 per cent)