AstraZeneca's statement in court papers has sparked health concerns worldwide, especially in countries like India where COVISHIELD has been given to a large part of the population. The British pharmaceutical giant has admitted that its COVID vaccine can lead to a rare side effect called TTS or Thrombosis with Thrombocytopenia Syndrome.
Covishield is the COVID vaccine developed by AstraZeneca and Oxford University and manufactured by the Serum Institute of India. On the 13th of January 2021, the vaccination campaign against SARS-CoV-2 was launched in India and started the administration of two types of vaccines known as Covaxin and Covishield. Covishield was approved for use in 49 other countries as well.
Though rare, its potential severity makes it worthy of consideration
"The AstraZeneca Covid-19 vaccination has given rise to a rare but serious concern: thrombocytopenia syndrome (TTS).In order to guarantee that vaccination decisions are well-informed, as a healthcare provider with expertise in neurointervention and stroke care, it is imperative that I provide information about this condition," Dr. Vipul Gupta, Chief of Neurointervention and Co-Chief of Stroke Unit, Artemis Hospital, Gurugram told ETimes-TOI.
"Low platelet counts, blood clots, and bleeding are the hallmarks of TTS, which mainly affects younger people after receiving the AstraZeneca Covid vaccine. Despite the exceedingly low overall incidence, its potential severity makes it worthy of consideration," he explained.
"Those who have had the AstraZeneca/Oxford COVID-19 vaccination should be especially cautious and watchful for signs of thrombosis with thrombocytopenia syndrome (TTS), especially if they are younger than 60. The AstraZeneca/Oxford vaccine Covishield is one of the main vaccinations used in India's vaccination campaign, thus Indians should be worried. Even though TTS is relatively rare, it is important that Indians report any strange symptoms they may have following vaccinations as soon as possible. This knowledge helps to preserve trust in the immunisation programme and guarantees that people receive prompt medical assistance when necessary," Dr. Yogendra Singh Rajput, Senior Consultant - Cardiology, Marengo Asia Hospital, Gurugram.
Thrombosis with Thrombocytopenia Syndrome (TTS) is a rare but serious condition associated with certain COVID-19 vaccines, particularly adenovirus vector vaccines like Johnson & Johnson's Janssen vaccine and AstraZeneca's vaccine. It involves the formation of blood clots (thrombosis) combined with low levels of platelets (thrombocytopenia), typically occurring within two weeks of vaccination.
Immunological reaction due to vaccination triggers TTS
"Though the precise process producing TTS is yet unknown, it is thought to be related to an immunological reaction brought on by the vaccination, which results in the creation of antibodies that stimulate platelets and cause clot formation. It is this atypical immunological response that sets TTS apart from ordinary thrombocytopenia situations," Dr. Gupta explains.
TTS symptoms can include severe headaches, abdominal pain, leg swelling, or shortness of breath. Symptoms usually appear two weeks following vaccination. Timely identification and intervention are crucial in reducing the likelihood of severe consequences.
Is Covaxin safe?
During the COVID pandemic, several vaccines were available: Covaxin, Covishield, and Sputnik-V, Covovax, Corbevax, ZyCoV-D, and other. Covaxin is India's first indigenous COVID vaccine and was developed by the corona vaccine manufacturer Bharat Biotech.
"People who have received the AstraZeneca/Oxford COVID-19 vaccination appear to be more susceptible to thrombosis with thrombocytopenia syndrome (TTS), especially women and younger persons under the age of 60. But it's important to remember that TTS is really rare and that vaccinations usually have more advantages than disadvantages, especially when you take into account how serious COVID-19 can be," Dr. Yogendra Singh Rajput adds.
As per information available on Bharat Biotech's portal, severe allergic reaction may very rarely occur after getting a dose of Covaxin. "These may not be all the possible side effects of Covaxin. Serious and unexpected side effects may
occur," it has stated.
Bharat Biotech on Thursday asserted that its Covid-19 vaccine Covaxin is safe and devoid of any side-effects amid AstraZeneca's admission that Covishield could cause complications in rare cases. In a statement, the company stated that Covaxin was developed with a single-minded focus on safety first, followed by efficacy.
The vaccine was evaluated in more than 27,000 subjects as part of its licensure process, Bharat Biotech stated.
It was licensed under restricted use in clinical trial mode, where detailed safety reporting was carried out for several hundred thousand subjects, it noted.
The vaccine was also evaluated by the Union Ministry of Health, it said.
Bharat Biotech's statement comes days after AstraZeneca admitted in court that its vaccine could in very rare cases cause thrombosis with thrombocytopenia syndrome.
(With inputs from PTI)