Make data public to allay vaccine fears
ASTRAZENECA (AZ) has stated that its Covid-19 vaccine, Covishield or Vaxzevria, may induce thrombosis with thrombocytopenia syndrome (TTS) in rare cases, resulting in neurological, cardiac, pulmonary and systemic organ complications related to clot formation in veins and arteries. Serious complications like a brain stroke and heart attack may occur. But the incidence of such complications is extremely low. According to the Melbourne Vaccine Education Centre, the risk of such serious complications is 2.6 per one lakh vaccinated (0.0026 per cent) individuals. Most cases occur within the first four weeks of vaccination. Beyond this, the chances of clot formation are almost nil.
AZ’s admission has created widespread concern among the public. The company’s subsequent withdrawal of the vaccine only served to exacerbate this concern, despite the firm claiming that the decision was due to ‘surplus availability’.
This data is not, in fact, new. The first dose of the Oxford-AZ vaccine outside of a clinical trial was given on January 2, 2021. The first incidence of clot formation was reported in February 2021. At the time, the global Covid-19 burden was colossal, with almost 4 million cases being reported every week. Hence, the WHO and the European Medicines Agency highlighted how the benefits of the vaccine far outweighed potential risks. Over the course of the year, around 2.5 billion doses were administered, with health authorities estimating that the vaccine saved approximately 6.3 million lives. In April 2021, the Delta variant wreaked havoc in India. Covishield was one of the few aids healthcare workers possessed to help them combat the health crisis.
One might reasonably ask, then, why the issue of TTS is being highlighted only now. In cases of mass panic, invariably, social media and the press play a role. Most of the Indian population has been vaccinated with Covishield. As a consequence, people have now begun fearing for their health and safety. Recently, during a car journey, my driver said he had heard that the Covid jab has serious side effects and that he was apprehensive as he had taken two doses of the vaccine. I reassured him with the information that I myself had taken three! Indeed, there is almost no reason to worry at this stage. In this situation, it is of paramount importance to lay scientific data before the public to help allay their fears and protect them from misinformation spread by anti-vaccine lobbyists. What we should also realise is that clot formation is far more common in patients suffering from Covid than in people who have received the AZ vaccine.
In the early days of the pandemic, even developed countries like the UK, Italy and the US faced the prospect of their health systems crumbling because of the sudden surge in hospitalisations and mortality. The horrors of the lockdown have left an indelible mark on our collective memory. The gravity and urgency of the situation forced governments, companies and research institutes to develop vaccines with groundbreaking speed and efficiency. Vaccine development, which earlier took at least 10-15 years, was accomplished in a matter of months. This is indubitably a remarkable achievement of science.
The mRNA vaccine from Pfizer BioNTech was approved in the UK (in December 2020). Soon, other countries approved a few other vaccines on the mRNA platform for emergency use, and then adenovirus vector-based Vaxzevria (of Oxford-AZ) was also approved. The Pune-based Serum Institute of India produced the Oxford-AZ vaccine and named it Covishield. This was also approved in India for emergency use and mentioned by the WHO in its emergency use list. At almost the same time, indigenous vaccines were produced in China and Russia, and India soon followed with its own indigenous vaccine, Covaxin, developed by Bharat Biotech.
The use of these vaccines in large populations globally did show the relative safety of these vaccines. In India alone, nearly 170 crore doses of Covishield were administered (90 per cent of the vaccinated people received it). These vaccines were the only tools for combating the spread of the virus because of the absence of effective antiviral drugs. The large-scale use and success of these vaccines globally is a testament to their safety and efficacy.
The mRNA vaccines (from Pfizer BioNTech and Moderna) were not used in the country because of the cost and technical issues, namely storage and transportation. In September 2023, the US FDA amended the emergency use of the Pfizer BioNTech Covid vaccine to include the 2023-24 formula as regular approval. The initial concern of specialised refrigeration for the transport and storage of these vaccines has also been overcome with new formulations. Moreover, mRNA vaccines are also easier to update when new variants emerge.
The withdrawal of the AZ vaccine is not linked to its TTS complications, which are extremely rare. The company, which is facing a lawsuit in the UK, has apparently withdrawn it as the Covid pandemic has subsided and because updated, better mRNA vaccines are available. The Covid vaccine story deserves its due credit for handling a serious health crisis.
