These vaccines are produced by inactivating or killing the organism by heat or through use of certain inactivating agents like formalin, beta-propiolactone or binary ethylenimine (BEI). Excessive treatment with the inactivating agent can destroy the immunogenicity whereas insufficient or inadequate treatment with the inactivating agent may lead the infectious pathogen capable of causing disease. These vaccines don’t produce a long-lasting immunity. Hence, booster does is required in certain time interval. These vaccines require to be administered along with adjuvant.

These subunit vaccines are produced by tailoring one or more antigenic part(s) of the bacterium or virus i.e. one or more antigenic component or subunit of a particular microorganism is utilized for vaccine production either the whole antigenic component (subunit vaccine) or through recombinant DNA technology (recombinant subunit vaccine). Here, antibody is produced in the vaccinated animal against the vaccinal component of the pathogen only. This antigenic component may be a protein obtained directly from the pathogen (peptide vaccine) or the peptide(s) produced from the pathogen itself through recombinant DNA technology (recombinant peptide vaccine) or a sugar (polysaccharide vaccine) etc. e.g. polysaccharide vaccine against pneumococcal infection in human. Conjugate vaccines are also one kind of subunit vaccine, in which vaccinal antigenic component of a pathogen is conjugated with a carrier protein for better antigen presentation and production of enhanced immunity. e.g. conjugate vaccine against Haemophilus influenzae in human. These vaccines do not produce any residual virulence unlike the live attenuated vaccines. Hence, chance of any breach in attenuation of the pathogen as well as becoming genetically altered due to passage in vivo or recombination can be avoided. Subunit vaccines don’t induce long lasting immunity. Hence, booster dose(s) is/are required.

DNA vaccines are new generation vaccines, which are constructed using the engineered plasmid containing the desired DNA of an immunodominant region which are administered with the help of micro-injection or gene gun delivery methods, so that antigen(s) is/are produced directly by cells of the recipient host for a long duration. There is no risk of reversion to virulence or no risk of infection are certain advantages of DNA vaccines over the conventional vaccines.

These viral vector vaccines are produced by using certain modified viruses as suitable vector platforms e.g. poxvirus, adenovirus based vectors, in which antigenic components of other pathogen(s) is/are inserted. Generally, the modified viral vector candidates used in vaccine production of such vaccines do not produce any overt clinical signs and symptoms in vaccinated animals. One of the major advantages of such vector platforms is the option of incorporating multiple antigenic components of different vaccinal candidates/pathogens as a single vaccine.

These are vaccines which contain one or more antigenic peptides encoded by immunodominant regions of the pathogen. These vaccines harbour the synthetic construct of the peptide(s) linked with the help of linkers, so that vaccinal antibodies are generated against the functional antigenic component(s) of the pathogen in the vaccinated animal host.

These are plant expressed subunit vaccines, where transgenic plants expressing one or more antigenic component(s) are produced and then propagated for production of edible unit containing the antigenic component(s) of the pathogen. It additionally targets for induction of mucosal immunity in the vaccinated organism apart from humoral and cell mediated immunity.

Marker vaccines are produced by use of deletion mutant vaccine candidates, those are devoid of one or more antigenic component(s). These vaccines can also be constructed using particular antigenic component(s) as subunit vaccine. These kind of vaccines induce antibody response against the particular antigen or group of antigens which is/are present in the vaccine, but not against the antigenic component(s) of the agent in its natural or wild form. Such marker vaccines offer promising application as compatible with ‘Differentiation of infected from vaccinated animal (DIVA)’ strategy, which is essential for effective implementation of disease eradication programme.

The messenger RNA (mRNA) vaccines are the new generation vaccines, produced by incorporating the mRNA in a carrier molecule. Once administered, the mRNA is presented to the recipient (host) immune system. Then the mRNA encodes the protein of interest in the vaccinated host. It results in development of both cell mediated as well as humoral immune response in the recipient host.

• Hester Biosciences: Poultry and Animal vaccines
• Indian Immunologicals (IIL): Animal vaccines
• Ventri Biologicals: Poultry and animal vaccines
• Biovet: Animal vaccines
• Brilliant Biopharma: Animal vaccines
• Indovax: Poultry vaccine
• Biomed: Animal and poultry vaccines
• Globion: Poultry vaccines

Many other companies sell the imported vaccines manufactured outside India