The Indian variant of Covid-19, also known as the Delta variant, could be linked to complications including hearing impairment and blood clots leading to gangrene, symptoms not typically seen in Covid patients.
While Covid-19 patients have long been at risk of other complications including increased strain on the heart and severe fatigue, which can continue for months after diagnosis, the reported new symptoms from the Indian variant will bring renewed focus on controlling its spread.
In England and Scotland, early evidence suggests the strain – which is also now dominant there – carries a higher risk of hospital admission.
Delta, also known as B.1.617.2, has spread to more than 60 countries over the past six months and triggered travel curbs from Australia to the US.
A spike in infections, fuelled by the Delta variant, has forced the UK to reconsider its plan for reopening later this month, with a local report saying it may be postponed by two weeks.
Higher rates of transmission and a reduction in the effectiveness of vaccines have made understanding the strain’s effects especially critical.
“We need more scientific research to analyse if these newer clinical presentations are linked to B.1.617 or not,” said Abdul Ghafur, an infectious disease physician at the Apollo Hospital in Chennai, southern India’s largest city.
Mr Ghafur said he was seeing more Covid patients with diarrhoea now than in the initial wave of the pandemic.
“Last year, we thought we had learnt about our new enemy, but it changed,” Mr Ghafur said. “This virus has become so, so unpredictable.”
Stomach pain, nausea, vomiting, loss of appetite, hearing loss and joint pain are among the ailments Covid patients are experiencing, according to six doctors treating patients across India.
The Beta and Gamma variants – first detected in South Africa and Brazil respectively – have shown little or no evidence of triggering unusual clinical signs, according to a study by researchers from the University of New South Wales last month.
Some patients develop micro thrombi, or small blood clots, so severe that they cause affected tissue to die and develop gangrene, said Ganesh Manudhane, a Mumbai cardiologist, who has treated eight patients for thrombotic complications at the Seven Hills Hospital during the past two months. Two required amputations of fingers or a foot.
“I saw three-to-four cases the whole of last year, and now it’s one patient a week,” Mr Manudhane said.
India has reported 18.6 million Covid cases thus far in 2021, compared with 10.3 million last year. The Delta variant was the "primary cause" behind the country's deadlier second wave and is 50 per cent more contagious than the Alpha strain that was first spotted in the UK, according to a recent study by an Indian government panel.
The surge in cases may have driven an increase in the frequency with which rare Covid complications are being observed. Still, Mr Manudhane said he was baffled by the blood clots he was seeing in patients across age groups with no past history of coagulation-related problems.
“We suspect it could be because of the new virus variant,” he said. Mr Manudhane is collecting data to study why some people develop the clots and others don’t.
Doctors are also finding instances of clots forming in blood vessels that supply the intestines, causing patients to experience stomach pain – their only symptom, local media have reported.
Some Covid patients are also seeking medical care for hearing loss, swelling around the neck and severe tonsillitis, said Hetal Marfatia, an ear nose and throat surgeon at Mumbai’s King Edward Memorial Hospital.
“Every person is showing different symptoms” in the second wave, she said.
The unusual presentations for Delta and a closely related variant known as Kappa, whose spread led to a fourth lockdown in the Australian city of Melbourne, are still being confirmed, said Raina MacIntyre, a professor of global biosecurity at the University of New South Wales in Sydney.
“In the meanwhile, it is important to take note of this and be aware of possible atypical presentations,” she said.
The most alarming aspect of the current outbreak in India is the rapidity with which the virus is spreading, including to children, said Chetan Mundada, a paediatrician with the Yashoda group of hospitals in Hyderabad.
Cases of Mucormycosis – a rare opportunistic fungal infection – have also been surging in India. It had infected more than 8,800 Covid patients and survivors as of May 22, forcing local health care authorities to call it an epidemic.
Even as India's outbreak begins to ease – daily infections have slipped to less than a quarter of the May 7 peak – the Delta variant is sparking outbreaks elsewhere, including hitherto virus havens such as Taiwan, Singapore and Vietnam, bolstering calls for mass immunisation.
German politician and scientist Karl Lauterbach said Tuesday the variant will probably become more prevalent in Germany too in the coming months.
“To avoid it completely seems unrealistic to me,” he said on Twitter in German. “The decisive factor is a very high vaccination rate, which reduces mortality.”
But with emerging evidence that Delta and at least one other variant may be adept at evading vaccine-induced antibodies, pharmaceutical companies are under pressure to tweak existing shots or develop new ones.
“New vaccines have to prepared with new variants in mind,” said Mr Ghafur. “We can’t get ahead of the virus, but at least we can least keep up with it.”