What are Inactivated Vaccines?
Inactivated vaccines use killed organisms to protect against subsequent infection with live organisms that cause disease.
Overview
Inactivated vaccines generally involve injection or inoculation of a person with killed organisms. The organisms used are generally virulent or disease causing strains, but they are no longer able to cause disease due to inactivation or killing of the organisms before inoculation. Inactivation or killing strategies can vary but generally involve the use of heat or chemical agents. Chemical agents are more commonly used as they can often maintain the structure of proteins or other biological molecule antigens that are important for eliciting an immune response. Inactivated vaccines are most effective for eliciting humoral immune responses as the inactivated organisms are unable to invade cells or replicate. Inactivated vaccines require strict quality control to ensure that killed organisms are fully inactivated before used for vaccination.
Existing Products
There are numerous inactivated vaccines currently in use. Examples of successful inactivated vaccines are listed here.
| Vaccine |
Description |
Notes |
| Cholera |
Two inactivated whole cell vaccines for cholera, Shancol and mORCVAX, were approved for use in India and Vietnam, respectively, in 2009. Because the duration of protection is limited, these vaccines will likely be limited to use in outbreak or potential outbreak scenarios. |
Cholera vaccines are not yet widely available, so the true impact of these vaccines has not been determined. |
| Influenza |
Inactivated vaccines for influenza have been in use since the 1940s. Influenza virus cultured in chick embryos is inactivated before injection. Due to high variability in virus strains from year to year, new vaccination is necessary each year. |
Influenza vaccines have the greatest impact on the elderly in the developed world. Because revaccination is needed each year, these vaccines are not widely used in resource poor settings. |
| Polio (Salk vaccine) |
Inactivated polio virus for vaccination was developed in 1952 using virus grown in tissue culture that is subsequently inactivated using the chemical formalin. It was FDA approved for the prevention of polio in 1955. |
As the first vaccine for polio, the Salk vaccine made an immediate impact on polio incidence in the U.S. The use of both the Salk inactivated and Sabin live attenuated polio vaccines has decreased the worldwide incidence of polio from 350,000 cases in 1988 to 1,652 cases in 2007. Because of these highly effective vaccines, polio is poised for eradication. |
| Rabies |
The first ever rabies vaccine was developed in 1885 by harvesting rabies virus from infected rabbits and allowing the virus to dry for 5-10 days, thus inactivating it. Although this vaccine has been replaced by more modern vaccine techniques, this discovery was an important advance for the vaccine community. |
Without treatment by post exposure vaccination, rabies is almost always fatal. The rabies vaccines was the first ever treatment for this infection and remains a key component of rabies treatment and prevention. |
Back to Top
Get Involved
To learn how you can get involved in neglected disease drug, vaccine or diagnostic research and development, or to provide updates, changes, or corrections to the Global Health Primer website, please view our FAQs or contact us at globalhealthprimer@bvgh.org.
PIPELINE
ANALYSIS
Inactivated vaccines benefit from a long history of use for a variety of infectious diseases. The relative strengths, weaknesses, opportunities, and risks for inactivated vaccines for viral, bacterial, and parasitic protozoan neglected diseases are summarized here. Examples of products currently in use or in development for relevant neglected tropical diseases are provided.
| |
Strengths |
Weaknesses |
Opportunities |
Risks |
| Inactivated: Bacterial diseases |
Relevant neglected tropical diseases:
Cholera (Shancol and mORCVAX, on market)
Tuberculosis (M. vaccae, phase III; RUTI, phase II)
ETEC (SBL 109, phase I) |
Inactivated vaccines are currently used for the prevention of cholera |
Primarily limited to production of humoral immune response which is not generally sufficient for intracellular infections |
May be useful in combination with other technologies as was done for Dukoral, a cholera vaccine that includes inactivated bacteria and a recombinant toxin protein |
Incomplete inactivation can lead to infection
Immune response may not be sufficient for all organisms |
| Inactivated: Viral diseases |
Relevant neglected tropical diseases:
Dengue (purified inactivated, pre-clinical) |
Method has been used successfully for multiple viral diseases |
Safety and efficacy in humans has not yet been evaluated |
Potential for combination with other dengue vaccines in development |
Incomplete inactivation can lead to infection
Immune response may not be sufficient for all organisms |
Get Involved
To learn how you can get involved in neglected disease drug, vaccine or diagnostic research and development, or to provide updates, changes, or corrections to the Global Health Primer website, please view our FAQs or contact us at globalhealthprimer@bvgh.org.
Tools for the development of inactivated vaccines vary widely based on the nature of the infectious organism. Please visit the disease profile ("Tools" tab) for each specific neglected disease if you would like to learn more about the availability of culture systems and other tools relevant for vaccine development.
Once organisms are cultured, heat or chemical methods can be used for inactivation. Chemical inactivation is more common as it generally is more effective for maintaining the structure of important antigens in the inactivated organism.
Get Involved
To learn how you can get involved in neglected disease drug, vaccine or diagnostic research and development, or to provide updates, changes, or corrections to the Global Health Primer website, please view our FAQs or contact us at globalhealthprimer@bvgh.org.