How do health concerns impact immunisation programs?

• Inability to be vaccinated due to health issues

• Allergic reactions: One of the main risks of vaccinations is an allergic reaction which may occur not as a result from the vaccine itself, but from a reaction to the medium in which the vaccine was cultured – for example, people who are allergic to yeast would need to be mindful that some of the older hepatitis B vaccines have yeast as a component

• Preservatives: In the manufacture of vaccines, certain chemicals are used as preservatives, including thiomersal, formaldehyde, aluminium phosphate, alum and acetone – some claim that these preservatives can affect the nervous system, and these claims have been investigated and have found no connection

How do social factors impact immunisation programs?

• Social factors

• Ethical concerns with the use of animals to produce vaccines: As viruses can only reproduce in living cells, the manufacture of viral vaccines reqquires host tissue, for example, influenza virus is cultured in chicken embryos, and consequentialy, some people are concerned about the treatment of animals in the production of vaccines

• Ethical concerns with the use of human tissue to produce vaccines: Many vaccines require human tissue as some viruses that cause disease in humans do not grow well in cells derived from other species, and in addition, the use of human tissue avoids the problems of cross-species infection from possible unknown viruses – the source of human tissue is a concern for many people

• Ethical concerns with informed consent: A key principle of ethics is informed consent, and this applies to trialling vaccines – there is some concern that trialling vaccines in developing countries may lead to their use in populations with low standards of education, meaning that people are not fully allways of the risks and may be open to exploitation by the vaccine’s manufacturer

• Ethical concerns with testing on animals: Prior to clinical trials on humans, most vaccines are tested on animals to identify problems that could arise with humans, such as mice, birds, amphibians and fish – legislation exists to limit the way that animals can be used, however, some people do not believe they should be used at all

• Concerns about promoting sexual activity in teenagers: Some people believe that vaccinating against the sexually tansmitted infection human papilloma virus will likely encourage teenagers to be sexually active

• Availability: Vaccines may not be readily available in all areas

How do cultural factors impact immunisation programs?

• Economic factors

• Cost of vaccine: The vaccines may be too expensive for some people to afford

• Commercialisation: The interests of commercial vaccine production may affect its use