MEDICINE FOR ALL

Subunit vaccines

Immune response:

• Subunit vaccines, like inactivated whole-cell vaccines do not contain live components of the pathogen. They differ from inactivated whole-cell vaccines, by containing only the antigenic parts of the pathogen. These parts are necessary to elicit a protective immune response
• This precision comes at a cost, as antigenic properties of the various potential subunits of a pathogen must be examined in detail to determine which particular combinations will produce an effective immune response witthin the correct pathway
• Often a response can be elicited, but there is no guarantee that immunological memory will be formed in the correct manner

Inactivated whole-cell vaccines

Safety and stability:

• Inactivated whole-cell vaccine have no risk of inducing the disease they are given against as they do not contain live components
• They are considered more stable than LAV vaccines.

Inactivated whole-cell vaccinations

Immune response:

• Inactivated-whole cell vaccines may not always induce an immune response and the response may not be long lived
• Several doses of inactivated whole-cell vaccines may be required to evoke a sufficient immune response

Inactivated whole-cell vaccinations

Inactivated vaccines are made from microorganism (viruses, bacteria, other) that have been killed through physical or chemical process. These killed organisms cannot cause disease.

Yellow fever (YF):

1. Hypersensitivity reactions

• Very rare
• Sensitivity to egg, which is commonly used to stabilize the vaccine, may explain at least some of these cases

2. Vaccine-associated neurotropic disease (encephalitis)

• Very rare
• Infants seem more susceptible to vaccine-associated neurotropic disease than the YF-vaccinated population at large

3. Vaccine-associated viscerotropic disease

• Very rare in children at 0.00001%
• The elderly seem more susceptible to reactions (very rare at 0.04-0.05%) than the YF-vaccinated population at large

Rotavirus:

• None reported to WHO
• To date, post-licensure surveilance does not indicate any increased risk of intussuception or other serious adverse reaction associated with the use of current rotavirus vaccines

Measles:

1. Febrile seizure 

• uncommon at 0.3%
• Adverse reactions, with the exception of allergic anaphylactic reactions, are less likely to occur after receipt of the second dose of measles vaccine

2. Thrombocytopenic purpura

• Very rare at 0.03%
• Adverse reactions, with the exception of allergic anaphylactic reactions, are less likely to occur after receipt of the second dose of measles vaccine

3. Anaphylaxis

• Very rare at 0.001%
• Allergic reactions to vaccine components including neomycin and the stabilizers gelatine or sorbitol, many follow vaccination.

Oral Polio vaccine (OPV):

• Vaccine-associated paralytic poliomyelitis (VAPP) in vacciness and their contacts
• Very rare at 0.00002-0.0004%
• An essential component of the global polio eradication campaign despite adverse reactions

Tuberculosis (BCG):

1. Fatal dissemination of BCG infection

• Very rare  at  0.000019-0.000159%
• Almost exclusively occurs in inadvertently immunized persons with severely compromised cellular immunity

2. BCG osteitis

• Very rare
• In the past BCG osteitis has been reported in connection with certain vaccine batches but now occurs very rarely

Five WHO recommended vaccines using LAV technology:

1. Tuberculosis (BCG)
2. Oral polio vaccine (OPV)
3. Measles
4. Rotavirus
5. Yellow fever