![virus5768628_640.jpg](https://files.peakd.com/file/peakd-hive/mintymile/znJ2XRH3-virus-5768628_640.jpg)
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[Serum Institute of India(SII) has developed a vaccine, Covishield](https://indianexpress.com/article/explained/simply-put-how-far-from-a-vaccine-now-7063054/). This vaccine is now in its final trial phases in India with the vaccine getting evaluated for  its effectiveness and resulting side effects.  The ongoing trials are conducted on 1600 participants with the vaccine administered on them and examined.

Reference Link -: https://indianexpress.com/article/explained/simply-put-how-far-from-a-vaccine-now-7063054/

### Covishield vaccine is derived from master seeds of vaccine AZD1222

Covishield is developed using the master seeds of vaccine AZD1222, that’s developed by Swedish-British company AstraZeneca along with the University of Oxford. 

### A peek at AZD1222 vaccine’s effectiveness

![corona5352818_640.png](https://files.peakd.com/file/peakd-hive/mintymile/TvrPpPHV-corona-5352818_640.png)
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AZD122’s effectiveness has been reported by the above entities who developed the vaccine based on the outcome of trials conducted on participants in the UK and Brazil. The report revealed that the effectiveness of the vaccine varied according to the dosage administered. 

In the first case scenario where half a dose of AZD122 vaccine was first administered with another full dose of vaccine given out the next month, the efficacy was 90%. 

In the second case scenario, when 2 full doses of the AZD122 vaccine got administered with a month’s gap between each dose, the efficacy was  62%.

This means that the dosage of half the vaccine accompanied by a full dose a month later was 90% effective in protecting those administered from getting Covid-19, while the dosage where 2 full doses of the vaccine was administered  a month apart was only 62% effective in protecting those administered from getting Covid-19.

There is a ongoing study on the possible reason for this outcome where there is variance in the effectiveness of the AZD122 vaccine when the doses are administered the above explained way. Experts feel that when half a dose is given initially  it readies the  body’s system to fight Covid-19 better, and later the body system’s response to a full dosage of the AZD122 vaccine gets strong thus being 90% effective in preventing Covid-19 from effecting the vaccine administered person.

On the other hand, it’s possible that initially when 1 full dose of the AZD122 vaccine is administered, it exhausts the body system so when another full dose is given a month later, the body’s immune response is not very strong to fight Covid-19. Therefore, in this scenario, the AZD122  vaccine is only 62% effective in protecting the vaccinated person from getting Covid-19.

### The effectiveness of Covisheid vaccine is to be seen

![vaccination5502034_640.png](https://files.peakd.com/file/peakd-hive/mintymile/YoMn0C1t-vaccination-5502034_640.png)
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It is to be seen how effective Covisheid is in its immunogenicity, that is its capacity in triggering the body’s immune response. It is possible that its performance may be similar to the AZD122 vaccine.

For a Covid-19 vaccine to be approved by the Indian Drug Regulator, it has to show that the effectiveness of the vaccine is 30%-50% . As of now since India does not have any Covid-19 vaccine, a vaccine that has the above mentioned efficiency percentage should not have a problem in getting approvals from the  Indian Drug Regulator for its use on the population.

Right now, if Covisheild should prove to have just 60% efficacy, it’s good enough, but a year later when other vaccines with better efficacy come by, it would have competition in the space and may not sustain in the market.