Delta variant infecting fully vaccinated people at faster rate

The Delta variant is the fastest, fittest and most formidable version of the coronavirus that causes Covid-19 the world has encountered, and it is upending assumptions about the disease even as nations loosen restrictions and open their economies, according to virologists and epidemiologists.

Vaccine protection remains very strong against severe infections and hospitalisations caused by any version of the coronavirus, and those most at risk are still the unvaccinated, according to interviews with 10 leading Covid-19 experts.

The major worry about the Delta variant, first identified in India, is not that it makes people sicker, but that it spreads far more easily from person to person, increasing infections and hospitalisations among the unvaccinated.

Evidence is also mounting that it is capable of infecting fully vaccinated people at a greater rate than previous versions, and concerns have been raised that they may even spread the virus, these experts said.

"The biggest risk to the world at the moment is simply Delta," said microbiologist Sharon Peacock, who runs Britain's efforts to sequence the genomes of coronavirus variants, calling it the "fittest and fastest variant yet."

Viruses constantly evolve through mutation, with new variants arising. Sometimes these are more dangerous than the original.

Until there is more data on Delta variant transmission, disease experts say that masks, social distancing and other measures set aside in countries with broad vaccination campaigns may again be needed.

Public Health England said that out of a total of 3,692 people hospitalised in Britain with the Delta variant, 58.3% were unvaccinated and 22.8% were fully vaccinated. In Singapore, where Delta is the most common variant, government officials reported on Friday that three quarters of its coronavirus cases occurred among vaccinated individuals, though none were severely ill. Israeli health officials have said 60% of current hospitalised Covid cases are in vaccinated people. Most of them are age 60 or older and often have underlying health problems.

In the United States, which has experienced more Covid-19 cases and deaths than any other country, the Delta variant represents about 83% of new infections. So far, unvaccinated people represent nearly 97% of severe cases.

"There is always the illusion that there is a magic bullet that will solve all our problems. The coronavirus is teaching us a lesson," said Nadav Davidovitch, director of Ben Gurion University's school of public health in Israel.

Meanwhile, with 39,361 people testing positive for coronavirus infection in a day, India's total tally of Covid-19 cases rose to 3,14,11,262, while the daily positivity was recorded above three per cent after 35 days, according to the Union Health Ministry data updated on Monday. The Covid-19 death toll climbed to 4,20,967 with 416 fresh fatalities. The active cases have increased to 4,11,189 and comprise 1.31 per cent of the total infections.