Business Standard

AstraZeneca vaccine: From its origin to side effects, all you need to know

Manufactured first in 2021, the AstraZeneca vaccine, known in India as Covishield, has been facing scrutiny over the years, with many countries banning it back in 2021 itself

Covishield, Vaccine

Photo: Wikimedia Commons

Abhijeet Kumar New Delhi
When the unexpected wave of the Covid-19 pandemic hit in 2020, medical science got busy finding a vaccine against the virus. Day in and day out, research on preventive vaccines became the only hope of billions of people locked down inside their homes.

The answer did come soon after. Amid hundreds of thousands of deaths around the world, the researchers achieved the unachievable within a matter of months. A vaccine was found and soon administered to people across the globe.

However, many in the scientific community raised their eyebrows at the rushed rollout of vaccines. They criticised the overruling of major safety guidelines and said checks were in place to ensure that vaccines would withstand the test of time.

But time had become gold dust.

Now, those apprehensions may have made a comeback. Yesterday, AstraZeneca, a prominent Covid-19 vaccine manufacturer that was administered to millions of people around the world, specifically most in India, admitted for the first time in court documents that its Covid-19 vaccine, sold globally under the brand names Covishield and Vaxzevria, among others, may lead to a rare, deadly side effect: Thrombosis with Thrombocytopenia syndrome (TTS).

What is the AstraZeneca Covid-19 vaccine?

The AstraZeneca vaccine, also known as AZD1222 or Covishield in India, is a viral vector vaccine designed to protect against the SARS-CoV-2 virus, the causative agent of Covid-19.

How does the Covishield vaccine work?

It works by utilising a weakened version of a common cold virus (adenovirus) found in chimpanzees, modified to carry the gene for a protein from the SARS-CoV-2 virus. Once injected, the vaccine prompts the human immune system to produce antibodies and activate T-cells to fight off the virus if the person is later exposed to it.

How was the AstraZeneca vaccine developed?

The AstraZeneca vaccine was developed through a collaboration between the University of Oxford and the British-Swedish pharmaceutical company AstraZeneca. Researchers at the University of Oxford had been developing a vaccine platform using adenovirus vectors for several years, and when the Covid-19 pandemic emerged, they quickly pivoted their efforts towards creating a vaccine against the novel coronavirus.

India's role in AstraZeneca vaccine development

Pune-based pharma firm Serum Institute of India (SII) entered into a strategic partnership with AstraZeneca and the University of Oxford in January 2021 to manufacture the Covishield vaccine for India and other low- and middle-income countries.

Leveraging its extensive manufacturing capabilities and expertise in vaccine production, this partnership allowed SII to produce the vaccine at scale to meet the enormous demand in India and globally.

Distribution of Covishield in India

The distribution of Covishield in India has been facilitated through collaboration with the Government of India and various state governments, as well as through international partnerships such as COVAX, a global initiative aimed at equitable access to Covid-19 vaccines.

As of April 30, 2024, over 1.7 billion doses of Covishield were administered in India as part of the world's largest vaccination program.

The AstraZeneca vaccine, with its relatively simple storage requirements (it can be stored for up to 6 months) and widespread availability, has played a crucial role in vaccination campaigns worldwide, including India's efforts to curb the spread of Covid-19 and achieve herd immunity.

What were the side effects of the Covishield vaccine?

The World Health Organisation lists the side effects of the AstraZeneca vaccine, including mild to moderate symptoms that are typically short-term and self-limiting.

Common side effects reported after receiving the AstraZeneca vaccine were discomfort at the injection site, feeling generally unwell, tiredness, fever, headache, feeling sick, joint or muscle pain, swelling, redness at the injection site, dizziness, sleepiness, sweating, abdominal pain, and fainting.

These side effects were said to be usually temporary and resolved without the need for hospitalisation.


Where was the AstraZeneca Covid-19 vaccine banned?

Following close scrutiny of the AstraZeneca vaccine, the product was banned in several countries. Denmark was the first country to suspend Covid-19 vaccine AstraZeneca, and Ireland, Thailand, the Netherlands, Norway, Iceland, Congo, and Bulgaria soon followed suit.

European countries, including Germany, France, Italy, and Spain, also stopped using AstraZeneca's Covid-19 vaccine in 2021 after multiple cases of blood clots were reported in patients who were administered the vaccine.

Canada, Sweden, Latvia, and Slovenia joined the league in banning the use of the vaccine in the same year. The vaccine was further banned in Australia, Indonesia, and Malaysia due to public concerns about its safety.

However, the World Health Organization (WHO) soon issued a statement in March regarding the AstraZeneca Covid-19 vaccine safety signals and still considered the vaccine's benefits to outweigh its potential risks, further recommending that vaccinations continue.

What is the new AstraZeneca controversy?

In court documents submitted to a UK court in February, the AstraZeneca company stated that a rare side effect known as Thrombosis with Thrombocytopenia Syndrome (TTS) can occur. It said, "It is admitted that the AZ vaccine can, in very rare cases, cause TTS. The causal mechanism is not known."

However, in the papers, it also said that even if there is no vaccination TTS can happen, adding that expert testimony will be required to determine causation in every individual case.

The Cambridge-headquartered British-Swedish multinational pharmaceutical and biotechnology company now faces a class-action lawsuit, which claims that its vaccine caused serious injuries and fatalities.

What is TTS, the condition associated with the Covishield vaccine?

Thrombosis with Thrombocytopenia syndrome (TTS) is a rare but serious condition associated with certain Covid-19 vaccines, particularly adenovirus vector vaccines such as the AstraZeneca vaccine and Johnson & Johnson's Janssen vaccine. TTS involves the formation of blood clots in combination with low platelet levels (thrombocytopenia).

The condition typically presents itself with blood clots occurring in unusual locations, such as the brain (cerebral venous sinus thrombosis) or abdomen, along with low platelet counts. The symptoms of TTS include severe headache, blurred vision, difficulty speaking, chest pain, abdominal pain, shortness of breath, and leg swelling, among others.

TTS has been thought to result from an immune response triggered by the adenovirus vector used in the vaccines, which activates platelets and forms blood clots.

Watch: Covishield can cause blood clots, low platelet count. Here's all you should know

Don't miss the most important news and views of the day. Get them on our Telegram channel

First Published: Apr 30 2024 | 10:26 AM IST

Explore News