Different Types of COVID-19 Vaccines
As COVID-19 pandemic hit the world, many scientists started developing its vaccines. Some vaccines have been proven effective and useful and many are in trials. So many people made different vaccines so that any of them could be used.
Following are the types of covid-19 vaccines:
These are the most conventional types of vaccines. A whole virus is used to trigger an immune response. There are two basic approaches in these types of vaccines. First is, live attenuated vaccine in which a weakened form of the virus is used that is able to replicate itself without causing any illness.
Inactivated vaccines are those that are not able to replicate but they still trigger an immune response without causing any illness.
Both the vaccines require cold storage but the live attenuated one can cause diseases in people having low immune system. However, inactivated vaccines are safe to use even for people with low immunity.
Subunit vaccines trigger the immune response by using pieces of pathogen. This reduces the risk of side effects and other diseases but the generated immune response might be weaker. Such vaccines often require adjuvants to help increase immune response.
Genetic material like DNA or RNA is used in nucleic acid vaccines to give the cells the instructions to make antigen. Antigen is the substance that induces immune system in the body. This genetic material is introduced in the body and when it gets into human cells, it uses the cells’ protein factories to make antigen to trigger immune response. The antigen is produced inside our body so the immune response can be strong. The advantages of such vaccines are that they are very easily manufactured and are relatively inexpensive. The disadvantage is that these types of vaccines are not fully regulated yet and no such vaccines have been licensed. Another con is that these vaccines are kept at ultra low temperature that can make it difficult to keep especially if the country does not have any mechanism for it.
Viral vector vaccines also work in the same manner as the nucleic acid vaccines, by giving cells the instruction to produce antigen. The difference is that there is a harmless virus used to give instruction that is different from the virus that is targeted by the vaccine. Viral vector vaccines can act similar to natural viral infection and hence gives a strong immune response. However, the vaccine can be less effective if people have already been exposed to the virus that is being used as a vector.