Explained: Why AstraZeneca has decided to withdraw its Covid ...

AstraZeneca had recently admitted in court documents that its vaccine against Covid-19 has the potential to cause TTS, a rare side effect associated with blood clotting.

The company at the moment has voluntarily withdrawn the "marketing authorisation" from the European Union for Vaxzevria. (Photo: Getty)

Days after it admitted, for the first time in court documents, the side effects of its vaccine, British pharmaceutical giant, AstraZeneca has announced a global withdrawal.

The company on Wednesday said that it had initiated the worldwide withdrawal of its COVID-19 vaccine due to a "surplus of available updated vaccines" since the pandemic.

"As multiple, variant COVID-19 vaccines have since been developed, there is a surplus of available updated vaccines," the company said.

According to the company, the decision to initiate a global withdrawal of the vaccine has been made owing to the presence of several other vaccines in the market. "Surplus of available updated vaccines," has forced AstraZenecca to withdraw the vaccine, as the sales have gone down.

AstraZeneca began moving into respiratory syncytial virus vaccines and obesity drugs through several deals last year after a slowdown in growth as COVID-19 medicine sales declined.

However, it is worth mentioning that AstraZeneca has sailed past market expectations for quarterly revenue and profit. According to Reuters, the second largest London-listed company by market value reported core earnings per share of $2.06 on a 19% year-on-year rise in revenue to $12.68 billion. That beat the profit of $1.92 per share on revenue of $11.84 billion expected by analysts in a company-compiled consensus.

The British pharmaceutical company, AstraZeneca, had recently admitted in court documents that its vaccine against Covid-19 has the potential to cause TTS, a rare side effect associated with blood clotting. The Covid-19 vaccine by the company was sold globally under the brand names Covishield and Vaxzevria.

Thrombosis with Thrombocytopenia Syndrome (TTS) is a serious and life-threatening adverse event.

While this was the first time that the company admitted it in court documents, it had in its clinical trials report revealed the adverse effects of the vaccine. The symptoms of the syndrome, which include severe or persistent headaches, blurred vision, shortness of breath, chest pain, leg swelling or persistent abdominal pain, typically show 4 to 42 days after vaccination.

What's interesting is that the firm's application to withdraw the vaccine from the European Union was made on March 5 and came into effect on May 7, according to the Telegraph, which first reported the development.

The AstraZeneca-Oxford vaccine, also known as AZD1222 or Covishield, operates on a viral vector platform. It employs a weakened version of a common cold virus (adenovirus), genetically modified so it can't replicate, to carry genetic material from the spike protein of the SARS-CoV-2 virus.

Upon vaccination, this modified adenovirus enters cells, instructing them to produce the spike protein. The immune system recognises this protein as foreign and mounts a response, producing antibodies and activating T-cells. This primes the immune system to combat the actual virus if encountered in the future.

Additionally, the adenovirus vector stimulates a broader immune response, potentially enhancing the vaccine's effectiveness. This approach has been used in various vaccines before, demonstrating safety and efficacy. The AstraZeneca-Oxford vaccine can be stored and transported at standard refrigeration temperatures, making it more accessible for global distribution.

While the company at the moment has voluntarily withdrawn the "marketing authorisation" from the European Union for Vaxzevria, similar applications are expected to be moved in other countries as well. This could mean in India too, where AstraZeneca manufactures the vaccine in partnership with Serum Institute of India under the brand name Covishield.

However, the decision should not be seen as alarming as sources in the Health Ministry told IndiaToday.in that the government has not purchased any Covid-19 vaccine in the last two years, and there is no indication of purchasing any more vaccines in the near future.

Officials at the Serum Institute of India (SII), on conditions of anonymity, in 2022, had said that there were no fresh orders from the government, and their supply commitments ended as of March 31, 2022. SII has a stock of 250 million doses of Covishield at its Pune facility for any future eventuality.

SII had in 2022 indicated plans to halve the production of Covishield as it had a 500 million doses inventory at its facility. Half of these were finished doses, while the remaining were bulk doses that were not converted to formulation.

(With inputs from Milan Sharma)

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