While Sydney tackles an outbreak fuelled by the highly-infectious Delta variant, a mutation of the variant is now prompting fears of a third wave in India.
The Delta Plus variant, which has an additional mutant K417N, has now appeared in three states in the once Covid-ravaged nation.
The Indian government announced there are now 22 cases of the variant in India as the Health Ministry declared it as a "variant of concern".
India has managed to suppress its daunting second wave which saw highs of more than 400,000 known daily infections, with daily cases now lower than 10 per cent of that peak.
But there are early fears the Delta Plus variant is far more transmissible than previous variants and could be resistant to vaccines.
The ministry said Delta Plus had shown signs of increased transmissibility while Dr VK Paul, Niti Aayog Member of Health, said the variant nullified the use of monoclonal antibody, however authorities say further testing is needed.
The early signs have sparked fears, voiced by state health authorities, the variant could cause a third wave, The Economic Times reported.
The government is now calling on the states of Maharashtra, Kerala and Madhya Pradhesh to step up containment, testing and tracking cases.
All India Institute of Medical Science director Randeep Guleria told India Today the new Delta Plus variant of Covid-19 is extremely transmissible and as seen with the Delta variant in Australia, transmission is occurring in fleeting situations.
The variant has also been detected in the US, UK, Portugal, Switzerland, India, Nepal, Russia and Japan.
Bumper vaccine day cannot be sustained, experts warn
On Monday, India vaccinated a record 8.6 million people as it began offering free shots to all adults, but experts doubted it could maintain that pace.
"This is clearly not sustainable," Chandrakant Lahariya, an expert in public policy and health systems, told Reuters.
"With such one-day drives, many states have consumed most of their current vaccine stocks, which will affect the vaccination in days to follow."
With the currently projected vaccine supply for the next few months, the maximum daily achievable rate is 4 to 5 million doses, Lahariya added.
The effort has so far covered about 5.5 per cent of the 950 million people eligible, even though India is the world's largest vaccine producer.
The nation's devastating second wave during April and May overwhelmed health services, killing hundreds of thousands. Images of funeral pyres blazing in car parks raised questions over the chaotic vaccine rollout.
Since May, vaccinations have averaged fewer than three million doses a day, far less than the 10 million health officials say are crucial to protect the millions vulnerable to new surges.
Particularly in the countryside, where two-thirds of a population of 1.4 billion lives and the healthcare system is often overstretched, the drive has faltered, experts say.
Maintaining the pace will prove challenging when it comes to injecting younger people in such areas, Delhi-based epidemiologist Rajib Dasgupta said.
The capital is also facing difficulties. Authorities in New Delhi said more than 8 million residents had yet to receive a first dose and inoculating all adults there would take more than a year at the current pace.
India has been administering AstraZeneca's vaccine, made locally by the Serum Institute of India, and a homegrown shot named Covaxin made by Bharat Biotech.
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