Less than one clotting event per million Covishield doses: govt

Almost two months after several European countries temporarily paused the use of the Oxford- AstraZeneca vaccine after reports of rare blood clots, the Health Ministry Monday said 26 potential thromboembolic events, or formation of clots in blood vessels, had been reported across the country following the administration of Covishield, as the vaccine is known in India. That works out to 0.61 cases per million doses, or a percentage of 0.000061.

Noting that this was “minuscule”, the ministry said Covishield “continues to have a definite positive benefit-risk profile” with “tremendous potential to prevent infections and reduce deaths” due to Covid-19. In case of Covaxin, it said, “no potential thromboembolic events” were reported.

“AEFI (Adverse Event Following Immunization) data in India showed that there is a very minuscule but definitive risk of thromboembolic events. The reporting rate of these events in India is around 0.61/million doses, which is much lower than the 4 cases/million reported by UK regulator Medical and Health Regulatory Authority (MHRA). Germany has reported 10 events per million doses,” the Health Ministry said.

Thromboembolic events include a blood vessel breaking loose, and carried by the bloodstream, plugging another vessel. Advisories will be issued for recipients to watch out for suspect thromboembolic symptoms till 20 days after receiving the vaccine, the ministry said.

The AEFI committee had completed an “in-depth case review” of 498 serious and severe events following immunisation with Covishield, of which 26 cases were reported to be potential thromboembolic events, it added. The committee’s conclusion was that “bleeding and clotting cases following Covid vaccination in India are minuscule and in line with the expected number of diagnoses of these conditions in the country”.

The ministry added that scientific literature suggests that “this risk (of blood clotting) is almost 70% less in persons of South and Southeast Asian descent in comparison to those from European descent”.

The 10 symptoms that beneficiaries were advised by the ministry to watch out for, and report the same to the health facility where the vaccine was administered, are: breathlessness; pain in chest; pain in limbs or pain on pressing limbs or swelling in limbs (arm or calf); multiple, pinhead size red spots or bruising of skin in an area beyond the injection site; persistent abdominal pain with or without vomiting; seizures in the absence of previous history of seizures with or without vomiting; severe and persistent headache with or without vomiting in the absence of previous history of migraine or chronic headache; weakness or paralysis of limbs or any particular side or part of the body, including face; persistent vomiting without any obvious reason; blurred vision or pain in eyes or having double vision; change in mental status or having confusion or depressed level of consciousness.

On April 7, the UK MHRA had issued advice concluding a possible link between the AstraZeneca vaccine and extremely rare blood clots.

A month later, on May 7, the UK’s Joint Committee on Vaccination and Immunisation (JCVI) advised that adults aged 30 to 39 without underlying health conditions should receive an alternative to the AstraZeneca vaccine for Covid where available and if it did not cause substantial delays in getting vaccinated.

The JCVI had, however, also reiterated the UKMHRA’s view that adverse events following the AstraZeneca vaccine were “extremely rare and, for the vast majority of people, the benefits of preventing serious illness and death far outweigh any risks”.

On April 23, the European Medicines Authority (EMA), backing the AstraZeneca vaccine, had said that the most serious side effects with it are “very rare cases” of unusual blood clots with low blood platelets, “which are estimated to occur in 1 in 100,000 vaccinated people”.

The EMA further stressed that the vaccine is “effective at preventing hospitalisations, intensive care unit admissions and deaths” due to Covid. “… There were insufficient data available from across the EU to provide further context on benefits and risks with regard to sex,” it said.

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