Covishield news: AstraZeneca admits its COVID vaccine can cause rare side effects; should you worry?

Covishield news: AstraZeneca, a British-Swedish pharmaceutical company, has admitted in its court papers that its Covid-19 vaccine, created by Oxford University researchers, can cause uncommon adverse effects such as blood clotting and low platelet count following immunisation. In India, the same vaccine, Covishield, developed by the Pune-based Serum Institute, has been delivered in 175 crore doses. Understandably, this raises concerns about the safety of the shot we all received. This was the most extensively used COVID-19 vaccination in the country.

What is the controversy regarding Corona vaccine?
According to a report in the Telegraph, AstraZeneca admitted for the first time in UK court documents that its Covid vaccine could pose a risk of a rare blood clot disorder. About 51 cases have been filed in the UK High Court against the pharmaceutical giant, claiming that its COVID-19 vaccine caused death and serious injury.

The report said victims and grieving relatives have demanded compensation, which is estimated to be worth up to £100 million. However, AstraZeneca is contesting those claims, admitting in a legal document submitted to the High Court in February that its Covid vaccine can cause TTS in very rare cases. Due to TTS, blood clots form in people and the number of platelets in the blood decreases.

An AstraZeneca spokesperson said, "We extend our sympathy to anyone who has lost loved ones or experienced health issues. Patient safety remains our top priority, and regulatory authorities have stringent standards to ensure the safe use of all medicines, including vaccines."

What is TTS?

Thrombosis Thrombocytopenia Syndrome (TTS) is an uncommon but deadly disorder marked by the production of blood clots (thrombosis) and low platelet counts in the blood. It is an uncommon adverse effect of immunisation, especially for adenovirus vector-based COVID-19 vaccines. Symptoms may include a strong headache, stomach discomfort, limb edema, and shortness of breath.

Is it dangerous?

Dr Ishwar, Secretary General, People's Health Organization-India Mumbai, said, "Once this virus is genetically modified or engineered so that it matches SARS-CoV-2 which causes Covid-19, so it works on the spike protein, so the vaccine has been incorporated with the spike protein genetic sequence."

Explaining the mechanism of possible TTS risk, the doctor said that the vaccine is injected into the arm, which is in the deltoid muscle. However, sometimes it also enters the bloodstream instead of going into the muscle. "Once it enters the bloodstream, the adenovirus in the vaccines acts like a magnet with a special attraction to a type of protein in the blood called platelet factor 4 (PF4)."

While PF4 is normally used by the body to promote coagulation in the blood, in rare cases, the body's immune system confuses it as a foreign body or foreign invader and then releases antibodies to attack it. 

"It has been theorised that such antibodies then react and combine with PF4 to form the blood clots that are most commonly associated with the vaccine," the doctor said. Such clots in the brain and heart could cause devastating adverse effects."

Should you worry?

According to doctors, we don't need to worry about it because this has happened to a very few people. The difficulty is to distinguish between complications that are caused by Covid itself or long-Covid or the vaccine. This remains a matter of debate for the scientific community and the legal fraternity.