AQA AS Biology

Revision Notes

2.6.6 Ethical Issues with Vaccines & Monoclonal Antibodies

Evaluating the Ethical Issues & Studies of Vaccines & Monoclonal Antibodies

Ethical issues associated with the use of vaccines

  • Use of animals:
    • All vaccines are tested on animals before they can move onto human-trials (testing on humans) but some people think animal testing is unethical
    • Animal-based substances are sometimes used in the production of vaccines but some people disagree with this
  • Human testing:
    • Even at the human-trial stage, a vaccine carries a small risk (the person being tested on may actually suffer from symptoms of the disease or other, unpredicted side-effects)
    • Volunteers may be at higher risk of contracting the disease if they think the trial vaccine will fully protect them but it actually doesn’t (e.g. they might have unprotected sex because they have had a trial HIV vaccine but they actually end up contracting the disease as a result)
    • Human volunteers are often paid to take part in vaccine trials. Ethical issues can arise if these volunteers feel pressured into doing this (and potentially being harmed in the process due to the reasons described above) because of their financial status (i.e. people who are struggling financially may be more likely to volunteer themselves)
  • Side-effects:
    • Some people refuse to take a particular vaccine due to the (usually very small) possibility of side effects
    • In fact, these people are often protected due to herd immunity (when a high enough proportion of a particular population has immunity, in this case through vaccination, the risk of anyone contracting the disease becomes very low). Other people (who have had the vaccination) may think this is unfair
    • Some parents refuse to let their children be vaccinated (for various reasons) but this is ethically questionable – should a parent be allowed to put their child at risk (arguably a much greater risk) of contracting the disease instead?
  • Epidemics:
    • When new pandemics occur (e.g. Covid-19) there is often a struggle as to who should be vaccinated first (e.g. should the elderly be given priority?)
    • There is also often a struggle between countries as to who receives the vaccines first and in what quantities (e.g. poorer countries may not be able to afford as many doses of the vaccine as richer countries – should all countries suffering from a pandemic have equal access to a vaccine?)

Ethical issues associated with the use of monoclonal antibodies

  • Ethical issues around monoclonal antibody therapies often revolve around animal rights issues:
    • New monoclonal antibody therapies are often tested on animals before they can move onto human-trials but some people think animal testing is unethical
    • Currently, animals are used to produce the cells from which the monoclonal antibodies are produced but some people think this is an unethical use of animals

Evaluating methodology, evidence and data relating to the use of vaccines and monoclonal antibodies

  • Claims, both negative and positive, are often made about vaccines (e.g. about their success rates or potential side-effects)
  • These claims need to be validated (confirmed) with scientific evidence before they are accepted (i.e. they need to be backed up by scientific research)
    • This often involves other scientists repeating the same study (using the same methodology) and trying to reproduce the results
    • Other scientists may also conduct other studies that try to prove the same theory or find the same results
  • Even then, it is important to evaluate the data used to support claims or new findings concerning vaccines, as well as the methodology behind this data
  • The importance of evaluating data behind claims and new scientific findings also applies to monoclonal antibody therapies and treatments

Example: The MMR Vaccine

  • The MMR vaccine is a vaccine against measles, mumps and rubella that is usually given to young children
  • A study published in 1998, the findings of which were based on 12 children with autism, concluded that the MMR vaccine might cause autism. It was later found that one of the doctors who worked in this study was acting as a consultant to some parents of autistic children who were suing the pharmaceutical companies that produced the vaccine
  • Evaluating the study:
    • The study is not very convincing as it had a very small sample size (just 12 children)
    • This increases the likelihood that the results were due to chance
    • The doctor may have been trying to gain evidence for the lawsuit against the vaccine
    • This would make the study biased (a biased person or a biased study favours one side or issue over another)
  • In 2005, a study was published on the incidence of autism in 30,000 children in an area of Japan between 1988 and 1996. The MMR vaccine was first introduced in this area in 1989 but stopped being administered in 1993. The results of the study are shown below:

Japan MMR autism graph, downloadable AS & A Level Biology revision notes

Number of children diagnosed with autism by age 7 per 10,000 children between 1988 and 1996 in Yokohama, Japan

  • Describing the data:
    • The number of children with autism continued to increase even after the MMR vaccine stopped being administered
    • For example, in 1992 (when children were given the vaccine) approximately only 75 per 10,000 children were diagnosed with autism by age 7 but in 1994 (when children were no longer given the vaccine) approximately 200 per 10,000 children were diagnosed with autism by age 7
  • Drawing conclusions:
    • This study suggests there is no link between the MMR vaccine and autism
  • Evaluating the study:
    • We can have greater confidence in the results of this study (compared to the one in 1998) as the sample size was very large (30,000 children)
    • This improved methodology means that the results are less likely to be due to chance

Exam Tip

If you are asked to evaluate the methods or results of an experiment or study in an exam, remember to consider three things: repeatability, reproducibility and validity.

Repeatability: were enough repeat readings or measurements taken? Would the person conducting the study get similar results if they repeated their own experiment?

Reproducibility: how do the results compare with other people’s results? Would other scientists get similar results if they repeated someone else’s experiment?

Validity: does the data answer the original research question? Were all variables other than those being changed or measured sufficiently controlled?

Ethical Issues with Vaccines & Monoclonal Antibodies

Prevention & control of cholera

  • Cholera occurs when people do not have access to effective sanitation facilities and access to clean water
  • It is difficult to prevent and control cholera because of:
    • The fast-growing cities in developing countries not having the appropriate infrastructure. They have limited funds for large-scale projects such as the provision of drainage systems, sewage treatment facilities and clean water supplies
    • Humanitarian crises (eg. displacement of people due to wars or natural disasters), which can cause the destruction of sanitation infrastructure and/or the provision of poor sanitation facilities in overcrowded temporary housing
    • The use of raw human sewage to irrigate crops
  • Prevention of cholera can occur through:
    • Providing adequate sewage treatment infrastructure
    • The provision of clean, piped water that has been chlorinated to kill bacteria (as this occurs in developed countries, cholera is very rare among them)
    • vaccination programmes in areas where cholera is endemic
  • Cholera can be controlled by:
    • Ready access to treatments such as oral rehydration therapy (a solution containing glucose, salts and water)
    • Monitoring programmes by the World Health Organisation (WHO)
    • Using antibiotics in severe cases (to reduce the risk of antibiotic resistance)

Prevention & control of malaria

  • The 3 main methods for reducing malaria are:
    • Reducing the number of Anopheles mosquitoes in an area
    • Reducing the chance of being bitten by these mosquitoes
    • Using drugs to prevent Plasmodium infecting humans
  • As Anopheles mosquitoes (specifically female mosquitoes) are the vectors that transmit Plasmodium between human hosts, the transmission cycle of malaria can be broken (or at least reduced) by reducing the number of these mosquitoes. This can be achieved by:
    • Spraying living areas with insecticides, such as DDT
    • Spreading oil over the surfaces of water bodies that the mosquitoes breed in such as ponds and irrigation or drainage ditches (the mosquitoes lay their eggs in water but the larvae breathe air at the water surface – an oil layer makes this impossible and kills the larvae)
    • Draining marshes and other unnecessary bodies of water
    • Ensuring ponds and irrigation or drainage ditches are stocked with fish that feed on mosquito larvae
    • Spraying these water bodies with a preparation containing the bacterium Bacillus thuringiensis, which kills mosquito larvae but is not toxic to other organisms
  • Unfortunately, mosquitoes lay eggs in even very small puddles and pools of water and therefore it is practically impossible to control all breeding sites using the methods listed above
  • Prophylactic (preventative) drugs (eg. chloroquine, mefloquine) are taken before, during and after a visit to a location where malaria is prevalent. However, the use of these drugs has resulted in drug-resistant strains of Plasmodium or the drugs are expensive and have disagreeable side-effects
  • One of the best ways to prevent malaria is to avoid being bitten in the first place. People in malarial zones should sleep under bed nets (which can also be soaked periodically in insecticide to increase effectiveness) and should try to avoid exposing their skin at dusk when mosquitoes are most active
  • In the 1950s, the World Health Organisation (WHO) coordinated a worldwide eradication programme. Whilst malaria was eradicated from some countries, the programme was mainly unsuccessful because:
    • Plasmodium became resistant to the drugs being used to try and control it
    • Anopheles mosquitoes became resistant to DDT and other insecticides being used against them
  • To control malaria governments, WHO and institutions (eg. universities) are focusing on:
    • Working within health systems to improve diagnosis
    • Improving the supply of effective drugs
    • Using drugs in combination to reduce drug resistance
    • Promoting appropriate methods to prevent transmission (eg. the use of biological controls to target the larvae and insecticide-treated bednets)
  • Recent scientific advances regarding the control of malaria are:
    • Simple dipstick tests for diagnosing malaria – this means a diagnosis can be made much faster and does not require a laboratory
    • The entire Plasmodium genome has been sequenced, which will help in the development of vaccines

Prevention & control of tuberculosis (TB)

  • TB is spread quickly from person to person when droplets released by the coughing or sneezing of an infected person with the active form of the illness are inhaled by an uninfected person (the droplets contain the TB-causing bacterium Mycobacterium tuberculosis)
  • The process of contact tracing (and the subsequent testing of those contacts for the bacterium) is an important method of controlling the spread of TB
    • Contacts are screened for symptoms of TB infection, although the diagnosis can take up to two weeks
  • Prevention for TB occurs through the use of the BCG vaccine (the only vaccine for TB)
    • The vaccine protects up to 70-80% of those who receive it, although its effectiveness decreases with age unless the person is exposed to TB
  • The form of TB that can be transmitted between cattle and humans (caused by Mycobacterium bovis) can be prevented by:
    • Routinely testing cattle for TB and destroying those that test positive
    • Pasteurising milk (kills any TB-causing bacteria present in the milk)
    • Ensuring meat is cooked properly

Prevention & control of HIV/AIDS

  • Preventing the spread of HIV is very difficult, as the virus has a long latent stage, which results in it being transmitted by people who have the virus but show no symptoms and do not know they are infected
    • This occurs because the virus can change its surface proteins, making it difficult for the human immune system to recognise it and for a vaccine to be developed
  • To prevent the transmission of HIV the following measures can occur:
    • Blood donations can be screened for HIV and heat-treated to kill any viruses
    • HIV-positive mothers and their babies can be treated with drugs (as HIV can be transmitted across the placenta, during birth and through breast milk
    • Condoms, femidoms and dental dams can be used to decrease the infection risk during sexual intercourse and oral sex by forming a physical barrier between body and fluids
    • Education programmes about how the virus is transmitted can be released into the community to encourage people to change their behaviours in order to protect themselves and others
    • Intravenous drug users encouraged not to share needles
  • Controlling HIV can occur by:
    • Contact tracing (and the subsequent testing of those contacts for the virus)
    • Screening blood donations
    • Public health measures widespread HIV testing of the population and education programmes
    • Needle-exchange schemes have been set up in some places to exchange used needles for new, sterile ones
    • Encouraging high-risk groups (eg. male homosexuals, prostitutes, injecting drug users) to be tested
    • Using anti-retroviral drugs
  • The socio-economic status of a person or country with HIV can determine how it is controlled. For example, HIV-positive mothers are advised not to breastfeed in high-income countries, however, in low- and middle-income countries breastfeeding offers protection against other diseases (eg. cholera)
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