Covaxin vs Covishield

Read more about Coronavirus

What to know about Covaxin?

Covaxin was developed by Hyderabad-based Bharat Biotech in collaboration with the Indian Medical Research Council (ICMR) and the National Institute of Virology. Bharat Biotech is a 24-year-old vaccine manufacturer with a portfolio of 16 vaccines and exports to 123 countries. The ICMR isolated SARS-CoV-2 and gave Bharat Biotech a strain for the development of an “inactivated” vaccine.

Inactivated vaccine means that the virus used for the vaccine has no chance of infecting or replicating the receiver inside the body after the Jab has been given. Bharat biotech had given a commitment that it has a stockpile of 20 million doses of Covaxin and is also aiming for 700 million doses by the end of the year.

Covaxin an inactivated vaccine—one of the oldest methods of human vaccination—meaning that whole, inactivated viruses are injected into the body to trigger an immune response. These whole batches of coronavirus must be grown, “killed” with a chemical or heat and then made into a vaccine, making it a longer process.

What to know about Covishield?

Oxford-AstraZeneca vaccine is produced locally by the Serum Institute of India, the world’s largest manufacturer of vaccines. It is said to produce more than 50 million doses a month. The vaccine, known as Covishield, is made from a weakened version of the common cold virus (known as adenovirus) from chimpanzees. It has been modified to look more like coronavirus, though it causes illness.

When the vaccine is injected into a patient, the immune system is prompted to start developing antibodies and to start attacking any coronavirus infection. Jab is given in two doses between four and 12 weeks apart. It can be stored safely at temperatures between 2-8 degrees centigrade, approximately the same as a domestic refrigerator, and can be delivered in existing health care settings.

Covishield Effectiveness

International clinical trials of the Oxford-AstraZeneca vaccine had shown that when people received a half dose and then a full dose, the efficacy was 90%. There was not enough clear information to approve the half dose – full dose idea. However, unpublished data suggest that keeping a longer gap between first and second doses increases overall efficacy of the Jab, which was found to be 70 per cent effective after the first dose in the vaccine subgroup.

What do we not know about Covaxin and Covishield?

The approval of a vaccine for use in large populations is given only after the drug regulator has been satisfied with the two-fold safety and immunogenicity test data, which also includes efficacy. Safety refers to whether a vaccine is safe for human use, taking into account all side effects and allergies.

In the case of both Covaxin and Covishield, the information is not yet available in the public domain. On an average, the effectiveness of the Covishield trial data on the basis of studies conducted in Europe and Brazil was 70 per cent. The average efficacy of its Indian trials is not yet known to the public.

Dosage

Both Covishield and Covaxin are two doses of Covid-19 vaccine. However, in an important concept considered to be an inadvertent error, the Covishield vaccine was found to be more than 90% effective when one and a half doses were given to the recipient. In India, SII trials were conducted using full two-shot doses during testing. The two shots of the Covishield vaccine have to be separated by six weeks.

In the case of Covaxin, the interval between the two shots has still not been prescribed by the Drug Controller General of India (DCGI), but its developer, Bharat Biotech, stated that the second shot would be given after 14 days.

Storage

Both Covishield and Covaxin vaccines are easy to store because they need to be kept at 2-8 degrees celsius. Most of the vaccines frequently used in India are kept at this range of temperature. This tends to make it easier and safer for all parts of the country to transport and store both Covid-19 vaccines locally.

Who cannot take Bharat Biotech Covaxin vaccine?

Covaxin is said to be not advisable in the following conditions:

Specifically, the company states that those who are pregnant or breast-feeding should not take the vaccine because its effects have not been studied in pregnant women and nursing mothers. It also states that “no scientific information is yet available on the appropriateness of the use of Covaxin along with other vaccines.”

Some minor side effects of Covaxin are:

Who cannot take Covishield vaccine?

Vaccine is contraindicated in conditions such as:

Some of the common side effects of Covishield are:

Not only the recent developments are taking India to the fore, but they also pave the way for economical and affordable vaccines to be made available. While the authorities have announced plans for free vaccination of priority groups in the first phase, both vaccines are also cheaper than their competitors. While the Covishield shot is likely to cost Rs.250-400, the Bharat Biotech vaccine model could cost less than Rs. 200 if experts are to be believed. No final word on the cost of Covaxin has also been received.