Updated: February 10, 2021 8:29:29 am
The rollout of the Oxford-AstraZeneca coronavirus vaccine will be paused in South Africa after researchers found it provided “minimal protection” against mild to moderate infections caused by the new variant circulating in that country. Experts in India have cautioned against pressing the panic button while underlining the need for continued surveillance of emerging variants.
The variant & the vaccine
All viruses change over time – most without a direct benefit to the virus in terms of increasing its infectiousness of transmissibility, and sometimes even limiting propagation. The variant circulating in South Africa, called 501Y.V2, has been found to be more transmissible than others. Preliminary studies based on genomic data show that the variant, which caused a second wave of infections starting late last year, has rapidly displaced other lineages circulating there, and suggested it is associated with a higher viral load, which may indicate potential for increased transmissibility.
According to a study widely reported over the weekend, the Oxford-AstraZeneca vaccine did not significantly reduce the risk of mild or moderate Covid-19 from 501Y.V2 variant. The study did not assess whether the vaccine helped prevent severe Covid-19 because it involved mostly young adults not considered to be at high risk for serious illness, reports have said. The study, conducted by the University of Witwatersrand and Oxford University, was based on early data from a small phase I/II trial.
Should Indians worry?
In India, the Serum Institute of India has partnered with Oxford for a version of the vaccine, named Covishield, which is one of the two being used in the ongoing vaccination drive. Scientists stress, however, that there is no cause for panic.
Leading vaccine scientist Gagandeep Kang said one should follow science. “An Oxford University release has told us that South Africa looked at data from young people that were given the vaccine and there appears to be no protection against mild or moderate symptoms. In India we do not have this variant so far,” she said.
Dr Samiran Panda, Head of the Epidemiology and Communicable Diseases Division at Indian Council of Medical Research (ICMR), said: “Any country’s decision regarding the administration of a vaccine programme should not be guided by the identification of a few numbers of individuals infected with a particular variant as the whole purpose is to develop immunity at the population level. There is a need to interrupt the chain of transmission of the virus irrespective of a particular variant circulating in the country or not. There will be additional benefit if the new variant can be prevented in the vaccination programme,” Dr Panda said.
Variants of concern
Two other mutants, detected first in the UK and Brazil respectively, are attracting global attention because they appear to spread faster. Everyone is waking up to the fact that vaccines developed against the predominant variant may not be effective against the new mutations, said Partha Majumder, National Science Chair, and Emeritus Professor at the Indian Statistical Institute, Kolkata.
Vaccine manufacturers are trying to tweak their vaccines. India has, however, been able to contain the spread of the new UK variant so far, he added. According to Health Ministry authorities, until January-end there were less than 170 cases of the UK variant in India.
From what has emerged so far, the South African variant is not only more contagious but more resistant towards existing antibodies. The UK variant is more contagious but not more resistant to pre-existing antibodies.
The UK variant (B.1.1.7) is becoming a concern in the US. While the numbers are still low, a study currently on a preprint server has found it is doubling every one-and-a-half weeks.
Dr Kang noted that it has been shown that the Oxford vaccine protects against the old and the UK variants. “Hence what needs to be done is follow the new emerging data, establish better human immunology in India, ramp up testing and make sure that we track variants intensively,” she said. “If a new vaccine is going to be needed then we can make new ones. The technology is there and vaccines work across multiple platforms.”
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