Globally, many vaccines are being delivered to citizens for preventing further transmission of coronavirus. Internationally, Zydus Cadila’s vaccines ZyCoV-D, Oxford-AstraZeneca, Pfizer, Bharat Biotech, Moderna and Novavax are in the final stages of trials and have also started to be administered in certain countries. In India, Russia’s Sputnik V is in trial and is being handled by Dr. Reddy’s Laboratories. Additionally, Bharat Biotech is working on another vaccine in collaboration with Thomas Jefferson University. Recently, in India two Covid vaccines - namely Covishield and Covaxin – have started to be administered.
Covishield has been developed by the University of Oxford and AstraZeneca. In India, it is being manufactured by the Serum Institute of India. On the other hand, Covaxin is an indigenous vaccine which was developed by Bharat Biotech and the National Institute of Virology. Covishield is a recombinant Covid-19 vaccine based on viral vector technology and Covaxin is a whole-vision inactivated coronavirus vaccine. Since January, frontline workers including healthcare workers have started to receive doses of the available vaccines. People aged more than 50 years and people having comorbidity issues are on the priority list.
Composition and requirement
For Covishield, 10 doses and for Covaxin, a total of 20 doses are required. 0.5ml is required for every dose of both of these vaccines and both are recommended to be scheduled in four weeks apart. Covishield, is the more acknowledged vaccine as it has 70.42% proven efficacies. In trials, Covishield has been used with precautions in concurrent illness, thrombocytopenia and coagulation disorders and for immunity compromised individuals. This vaccine has not been tested in pregnant or lactating women and in children aged less than 18 years.
In a press release, the Serum Institute has declared that the ingredients of Covishield are namely L-Histidine, L-Histidine hydrochloride monohydrate, Polysorbate 80, Magnesium chloride hexahydrate, Ethanol, Sucrose, Sodium chloride, Disodium edetate dihydrate (EDTA) and water for injection. People who are allergic to any of these ingredients are not recommended to take Covishield.
Adverse events following immunisation (AEFI) of Covishield are injection site tenderness and pain, headache, fatigue, myalgia, malaise, pyrexia, chills and arthralgia, nausea. In some rare cases, Lymphadenopathy can be seen according to medical reports. The vaccine manufacturers have said that the vaccine recipient must declare his or her medical conditions to healthcare providers for better assessment. Additionally, any symptoms of anaphylaxis will have to be mentioned clearly.
Similarly, the AEFI of Covaxin are injection site pain, fatigue, fever, body ache, abdominal pain, nausea and vomiting and dizziness, giddiness, tremor, sweating, cold, cough and injection site swelling. People having a history of allergy, fever or bleeding disorder and who are on some medication or are immunity compromised have been recommended not to take Covaxin. Hypersensitivity to the ingredients of the vaccines is the said contraindication. Covaxin is contraindicated for lactating or pregnant women.
Presently, the vaccines are not quite accessible for the masses in India. It is only the frontline workers who are receiving the doses and the central government is bearing the cost for them.
Dr. Subhrojyoti Bhowmick, Consultant Clinical Pharmacologist and Clinical Director, Peerless Hospitals (Kolkata) told BE, “I have taken Covishield. A section of experts prefers Covishield because it has published data of all trials. In the case of Covaxin, the data were not available initially. Recently the data for phase I trial has been published.”
The Union Ministry of Health and Family Welfare has stated that even the population who has recovered from Covid-19 (they have prior history with this virus) are also advised to receive the complete schedule of the vaccine to build a better immunity system. But a section remains sceptical about the safety and efficacy of the vaccines. The developers, manufacturers along with the government are trying to spread positive awareness. Till January 23, midnight, according to government data, 13,90,592 people have been vaccinated and the number is increasing.