Two countries, two strategies on the AZ-Oxford vaccine’s second dose

PT Jyothi Datta Mumbai | Updated on May 16, 2021

India staggers the second dose, even as UK looks to advance it, concerned over the B.1.617 variant.

Just as India decided to delay giving the second dose of the AstraZeneca-OxfordUniversity vaccine by 12 to 16 weeks from the first one, the United Kingdom is set to advance its time to the second dose – a decision prompted by the virus variant, B.1.617.2, that originated from India.

The UK Prime Minister Boris Johnson said on Friday, they would accelerate their Covid-19 vaccination programme to try and contain a fast-spreading variant first identified in India, agency reports from the UK said. The time to the second dose was advanced to eight weeks from the first in those over-50 years and the clinically vulnerable.

Before India decided to stagger the second dose of the AZ vaccine earlier this week, the gap between the two doses of this vaccine was 6-8 weeks. The decision to delay dose 2 has drawn criticism from some quarters, given the vaccine shortages being reported from different States.

“But both decisions are right in their respective contexts,” explains Dr Swapneil Parikh. The UK has a larger percentage of its population vaccinated and it has multiple vaccine options and more hospital capacity available.

“Besides, they have a timeline set to opening up and a widely spreading variant could upset that,” says Dr Parikhwho is co-author, “The Coronavirus: What you need to know about the global pandemic.”

In India, the decision to stagger the second dose makes sense because the aim is not to “flatten the transmission curve, but the hospitalisation curve,” he says. The percentage of the population covered by vaccination here is very small, health systems are on the edge and can really take no more, he adds. “And hospitalisation reduction can be achieved by the protection from the first dose,” Dr Parkih explains.

“These are two different strategies that are correct in their respective context,” he says, also pointing out that in the UK, those below 40 years are given a choice of vaccine other than AZ, following the risk of rare blood clots.

In fact, there too, India expanded its vaccination to people below 40 years, even as the UK limited the use of the AZ vaccine in this population due to the risks involved. The AZ vaccine is one of two vaccines being rolled out in India, the other being Bharat Biotech’s Covaxin.

“The risk-benefit analysis is a dynamic process,” says Parikh, pointing to the percentage of population vaccinated daily and their age profile, vulnerability and so on, that would have played a role in the decision.

The B.1.617 variant that originated from India has been recently classified as a “variant of concern” by the World Health Organization, following which more countries have stepped up efforts to protect against this highly transmissible strain.

Published on May 16, 2021

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