AQA A Level Biology复习笔记2.6.6 Ethical Issues with 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. 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

   

• 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:

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