Worrying Delta variant Covid-19 complications raise urgency of vaccine roll-outs

Coronavirus variant identified as significantly more dangerous than previous strains

Girls at a Covid-19 care centre in New Delhi, India. Reuters

As the Delta variant causes a surge in coronavirus numbers in the UK, in the country where the variant originated, India, it has been associated with several cases of gangrene.

The gangrene, stroke and other related symptoms are linked to hypercoagulation, a tendency for the blood to clot more easily than usual.

With India’s second wave causing the total number of Covid-19 deaths in the country to surpass 350,000, the emergence of the particularly unpleasant complications has been an additional cause of alarm.

“There’s definitely an increase in the numbers of strokes and gangrene with this variant. Last year the caseload was the same in my hospital, but I’m seeing more of these cases this year,” Dr Ganesh Manudhane, a consultant in cardiology at Seven Hills Hospital in Mumbai, said.

In the past three months, Dr Manudhane saw about 10 patients with symptoms linked to hypercoagulation, often involving gangrene, the localised death of tissue.

Reports say patients have had to have fingers and even feet amputated, but Dr Manudhane said often their lives cannot be saved.

“We have carried out amputations, but in some of these cases, the patients are having severe pneumonia. The mortality is high in such cases,” he said.

A wide collections of symptoms have reportedly been linked to hypercoagulation, including stomach pain caused by clots in blood vessels that supply the intestines. There have also been reports of hearing loss and joint pain among patients affected during India’s second wave.

As has been widely reported in recent weeks, a fungal infection called mucormycosis, also referred to as black fungus, has killed hundreds of Covid-19 patients in India in the past few months. Other countries including Pakistan and Russia have also been affected.

“There must be some association with this variant and mucormycosis,” Dr Manudhane said. “Last year we never found these problems of fungus, but this year we’re finding these problems.”

The Delta variant was first detected in India in October but is now present in more than 60 countries and, if the UK’s experiences are anything to go by, it may become much more common in many of them.

In early April it accounted for just one per cent of UK cases, but Health Secretary Matt Hancock said on Thursday that 91 per cent of new infections were caused by the variant.

The variant has also been blamed for surges in cases in the north-west, which could delay a final lifting of lockdown restrictions across England, with the country having recently experienced its biggest rise in cases since early last year.

Public Health England said the Delta variant appears to be 64 per cent more transmissible than its Alpha counterpart, which was first observed in southern England in September.

That would mean the Delta variant spreads more than twice as easily as the original coronavirus that emerged in Wuhan in China in December 2019.

The way the mutations carried by the variant alter how viral particles bind to receptors on cells are thought to account for changes in transmissibility and symptoms.

Although the Delta variant spreads significantly more easily, its ability to evade the protection conferred by vaccines appears to be more modest.

In the US, where only about six per cent of cases are caused by the variant, the government reported that laboratory tests found only a “modest decrease” in the ability of extracts from the blood of previously vaccinated or infected individuals to neutralise the strain.

Vaccine efficacy 

Similarly, two doses of the Pfizer-BioNTech vaccine are thought to be 88 per cent effective at preventing symptomatic illness in those infected with the Delta variant, compared to 93 per cent with the Alpha variant.

With the Oxford-AstraZeneca shot, vaccine effectiveness against symptomatic disease after two doses is reduced from 66 per cent with the Alpha variant to 60 per cent with the Delta variant.

Just five per cent of people in English hospitals after being infected with the Delta variant are fully vaccinated, indicating that a full course of vaccination remains highly effective against the variant.

However, one dose of either the Pfizer-BioNTech or Oxford-AstraZeneca vaccines offers only 33 per cent protection against the variant, compared to 50 per cent protection against the Alpha variant, according to figures from Public Health England.

Dr Anthony Fauci, chief medical adviser to the US president and director of the US National Institute of Allergy and Infectious Diseases, said the variant may be linked to a higher risk of more serious disease and hospital admission.

That has been the case in the UK, with Public Health England data indicating there were 2.61 times the risk of hospital admission and 1.67 times the risk of admission to an accident and emergency department compared to the Alpha variant.

Clinicians reported different symptoms among recently infected people, according to Prof Paul Hunter, a professor in medicine at the University of East Anglia in the UK.

“You’re getting more cold-like symptoms, sore throat and sneezing,” he said. “This doesn’t surprise me because if you look at the other human coronaviruses – there are mainly four – they essentially cause the common cold in most of us.”

He said that damage to the sense of smell, one of the symptoms of coronavirus infection, does not appear to be reported now.

Changes in the type of symptoms seen most commonly may, though, not be simply down to changes in how the Delta variant affects people, but could be because people have previously been infected or had a vaccine.

In India, the Delta variant appears to be linked to an increased proportion of younger people falling sick, according to Dr Manudhane.

“We used to see last year [people] above 60,” he said. “Now we’re seeing 40 to 60 years and a very young age – 20 to 40. Even the younger patients are presenting with serious symptoms.”

While significant impacts from the Delta variant seem to be limited to a few countries so far, experts are concerned that it may become increasingly common given its increased infectiousness.