Brazil: Sputnik V vaccine supply had live cold virus

The Health Regulator of Brazil recently announced that the Sputnik V vaccines of Russia carried live cold virus. It has thus raised questions about the integrity of the manufacturing process of the virus.

This issue has come up due to the Adeno Virus vector.

The Adeno Virus Vector

Vector means the carrier of the virus. In this case the COVID-19 virus. These vectors carry only a portion of the virus which is generally referred to as antigen.

The Adeno Virus is normally used as a vector as they induce innate (natural) and adaptive immune responses.

What is the issue with Adeno virus based COVID vaccines?

Adeno virus normally causes mild respiratory illness in humans. However, in vaccines, they are modified in such a way that they cannot replicate. Their structure is edited to carry the DNA instructions for human cells to develop immune system against COVID-19. That is, it carries a part of dead COVID-19 material and also it trains the immune system to fight against this virus.

Adeno Virus in Sputnik V

Usually, the adeno virus-based vaccines are administered in single shot. This is because, the adeno virus naturally occurs in humans. People with a weak immune system are more likely to get an adeno virus infection.

However, Sputnik V which is also an adeno virus-based vaccine is administered in two shots. In the first shot, adeno virus type 26 Ad 26 is administered and in the second shot adeno virus Ad5 is administered.


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