Biology
/
Vaccines

Vaccines

Shiken premium Upgrade Banner

Vaccines are substances that can help your body fight against a specific disease. They contain weakened or dead versions of the virus or bacteria that causes the disease. When you get a vaccine, you become vaccinated. This means that your body can recognize the virus or bacteria and create an immune response to fight it off if you ever come into contact with it again.

Getting vaccinated is an example of artificial immunity. This means that you can build up immunity to a disease without actually getting sick from it. Most people who get vaccinated won't experience any symptoms of the disease, since the vaccine only contains a weak version of the pathogen.

It's important to get vaccinated to protect yourself and others around you from getting sick. By getting vaccinated, you can help prevent the spread of diseases and keep yourself and your community healthy. So, make sure to stay up-to-date on your vaccinations and talk to your healthcare provider if you have any questions or concerns. Remember, prevention is key! Keywords: vaccines, vaccination, immune response, disease, immunity, pathogen, virus, bacteria, community, healthcare provider.

How do vaccines work?

When you receive a vaccine, the weakened pathogen is introduced into your body either through an injection or orally. However, vaccines are usually given as injections because the weakened pathogen can be broken down in the stomach if taken orally.

After vaccination, your body's immune system is triggered to respond to the foreign antigens present in the vaccine. This primary immune response involves T Helper cells activating B plasma cells to produce specific antibodies against the pathogen's antigens.

The primary response also leads to the production of memory cells, which provide long-term immunity. If the same pathogen is encountered again, memory cells will quickly produce specific antibodies in a secondary response, preventing symptoms of the disease from developing.

In some cases, booster vaccines may be necessary to ensure that memory cells are still present in the body. These secondary or tertiary vaccines can help maintain immunity and protect against future infections.

Examples of vaccines

The MMR vaccine is usually given to children in two doses, at least 4 weeks apart, during infancy. This vaccination provides long-term protection against measles, mumps, and rubella.

The HPV vaccine is given to children in the UK when they are 12 or 13 years old. This vaccine protects against the human papillomavirus, which is a group of very common viruses. Some types HPV are and can lead to the development of certain types of cancer, such as cervical cancer, vaginal cancer, vulval cancer, anal cancer, cancer of the penis, and some cancers of the head and neck. By getting the HPV vaccine, you can protect yourself from these types of cancer and the risks associated with contracting HPV.

Types of vaccine

There are several types of vaccines including attenuated pathogens, inactivated vaccines and mRNA vaccines (not widely used) which show promise for the future.

Live attenuated vaccines

The vaccines mentioned above, such as the MMR vaccine and the yellow fever vaccine, contain whole pathogens that have been weakened. The weakened pathogens in these vaccines multiply slowly, allowing the body to recognize the antigens on the pathogen and produce a primary immune response without becoming overwhelmed and showing symptoms of the disease.

However, these vaccines may not be suitable for individuals with weak immune systems, as their primary immune response is slower, and the pathogen may cause symptoms before antibodies can be produced. Live attenuated vaccines, such as the MMR vaccine and the yellow fever vaccine, typically produce longer-lasting and stronger immune responses.

Inactivated vaccines

Unlike live attenuated vaccines, inactivated vaccines contain whole pathogens that have been killed or subunits of the pathogens, such as proteins. are more suitable for individuals systems because do living pathogens, reducing the risk of causing disease.Inactivated vaccines may also contain adjuvants, which are substances that enhance the body's immune response to an antigen. While adjuvants can improve the effectiveness of the vaccine, they may also cause local allergic reactions, such as a sore arm, in some individuals.

Overall, inactivated vaccines are a safer option for individuals with weakened immune systems, as they do not contain live pathogens and are less likely to cause adverse reactions.

mRNA vaccines

Thank you for the prompt. Here's your requested table:

| Vaccine Delivery Method | Description Examples |
| --- | --- | --- |
| Live attenuated vaccines | Contain weakened pathogens that multiply slowly, allowing the body to produce a primary immune response without becoming overwhelmed and showing symptoms of the disease | MMR vaccine, yellow fever vaccine |
| Inactivated vaccines | Contain killed pathogens or subunits of the pathogen, such as proteins, and are more suitable for individuals with weak immune systems as they do not contain living pathogens | Hepatitis A vaccine, polio vaccine |
| mRNA vaccines | Deliver only the genetic code, mRNA, which teaches the body's cells to produce antigen proteins specific to the virus, triggering an immune response | Pfizer-BioNTech COVID-19 vaccine, Moderna COVID-19 vaccine |

An overview of vaccine delivery methods

Herd Immunity

Herd immunity is achieved when a sufficient proportion of the population has been vaccinated to break the chain of a pathogen's transmission, making it difficult for that pathogen to spread through the population and infect vulnerable groups who are unable to receive a vaccine. Pathogens are typically transmitted through close contact between individuals, therefore if most of the population is immune and cannot be infected, then it is very unlikely that a susceptible person who is unvaccinated will come into contact with a carrier of the disease.

Herd immunity, therefore, helps to protect individuals who cannot be vaccinated. Babies and the very young cannot be vaccinated because their immune systems are still underdeveloped and not yet fully functional, putting them at risk of serious illness if exposed to even a weaker form of the vaccine pathogen. Those who are ill or have compromised immune systems due to autoimmune diseases or immunosuppressant drugs also cannot be vaccinated due to the medical risks it poses.

Herd immunity

How is a successful vaccination program run?

In short, the criteria are: Sufficient quantity produced. Economically viable. WIdely available. Few or no side effects. Suitable ways for producing, storing and transporting the vaccine. Access to technologically advanced equipment.

Economical viability

The vaccine must be economically available.  In other words, it must cost a reasonable amount of money to research, produce, and deliver the vaccine. If the vaccine is too expensive to produce there is a risk that not enough will be made to vaccinate enough people to produce herd immunity. In addition, the vaccine must also be made economically available to the population, people should be able to afford the vaccine if it isn't free and must be able to afford associated costs such as transport to the vaccine centre.

Side effects

Vaccine developers should also work to ensure that there are few, if any, side effects from the vaccine. This is because fewer people will be likely to get the vaccine if they know that they will experience unpleasant side effects from it.

Suitable equipment and handling available

There must also be suitable ways of producing, storing, and transporting the vaccine. Researchers should have access to technologically advanced equipment and there should be hygienic conditions to store the vaccine in. Many vaccines must be refrigerated or kept cool, so vaccine centres should have access to fridges and freezers at the correct temperatures to keep the vaccine good for use.

Problems with vaccines

It is important to note that vaccines are not a total 'cure-all' and often do not entirely eradicate a disease from the population. Many also have ethical oppositions to the way vaccines are manufactured, as well as how they are used. These issues must be taken into account when considering the success of vaccines to combat diseases in populations.

Why vaccines are not completely foolproof"?

You are correct. While vaccines are very effective at preventing the spread of infectious diseases, a small percentage of vaccinated individuals may not develop immunity due to certain factors. One such factor is an individual's immune system. People who have weakened immune systems, whether due to a medical condition or medication, may not respond as effectively to the vaccine as healthy individuals.

Another factor that can lead to vaccine failure is timing. Vaccines require time to stimulate an immune response, and some individuals may become infected the virus before the vaccine has time to take effect. This is why it's important to continue practicing preventive measures, such as wearing masks and social distancing, even after receiving the vaccine.

Moreover, it's important to note that vaccines are not 100% effective. While they significantly reduce the risk of contracting the disease or experiencing severe symptoms, there is still a chance of becoming infected. This is why public health officials stress the importance of herd immunity, which occurs when a large percentage of the population is vaccinated, making it difficult for the disease to spread.

In conclusion, while vaccines are an effective tool in preventing the spread of infectious diseases, they are not foolproof. It's important to continue practicing preventive measures and work towards achieving herd immunity to protect individuals who may not be able to develop immunity from the vaccine.

Reasons why people might avoid getting vaccinated

Individuals may choose not to be vaccinated for religious, ethical, medical, or political reasons.

For example, during the coronavirus pandemic, many individuals refused to be vaccinated due to ideological beliefs. Misinformation around vaccines, such as that they cause autism, and conspiracies such as that vaccines contain government tracking devices, can seriously damage the effectiveness of community vaccination programs and undermine trust in medical professionals.

Pathogenic mutations

The ability of pathogens to mutate is a major challenge when it comes to developing effective vaccines. Pathogens such as the influenza virus can mutate rapidly, making it difficult to develop a vaccine that provides long-term protection. Influenza viruses are constantly evolving, and new strains emerge each year, which is why the flu vaccine needs to be updated annually to provide protection against the current strains.

Antigenic variability is a significant problem for vaccines since the immune system may not be able to recognize the mutated pathogen, making the vaccine less effective. This is why scientists must continually monitor the pathogen and develop new vaccines or modify existing ones to keep up with the changes.

In some cases, there may be so many varieties of the pathogen that it is practically impossible to vaccinate against them all or to develop a single vaccine effective against each mutated strain. This is particularly true for viruses such as the common cold, which has over 100 varieties and the variability remain an essential tool in preventing the spread of infectious diseases continuing to research and develop new vaccines, scientists can stay one step ahead of the pathogens and help protect individuals from serious illness or death.

Mutations in the influenza virus

Pathogens can hide from the blood cells

Pathogens may also be able to escape the body's immune system through 'hiding' from white blood cells. This may occur by pathogens concealing themselves within cells, a common technique for viruses, or in other places out of reach of defense mechanisms. For example, cholera bacteria occupy the intestines. This is called antigenic concealment.

Vaccines and ethical issues

Ethical issues include animal testing, human trials, monetary issues and others.

Animal trials

The development of new vaccines often involves the use of animals for testing before clinical trials progress to testing new vaccines on humans. Some question the ethics of animal testing as animals cannot consent to be tested. In addition, trial vaccinations often have unknown and potentially harmful side effects.

Human trials

The ability of pathogens to mutate is a major challenge when it comes to developing effective vaccines. Pathogens such as the influenza virus can mutate rapidly, making it difficult to develop a vaccine that provides long-term protection. Influenza viruses are constantly evolving, and new strains emerge each year, which is why the flu vaccine needs to be updated annually to provide protection against the current strains.

Antigenic variability is a significant problem for vaccines since the immune system may not be able to recognize the mutated pathogen, making the vaccine less effective. This is why scientists must continually monitor the pathogen and develop new vaccines or modify existing ones to keep up with the changes.

In some cases, there may be so many varieties of the pathogen that it is practically impossible to vaccinate against them all or to develop a single vaccine effective against each mutated strain. This is particularly true for viruses such as the common cold, which has over 100 varieties and the variability remain an essential tool in preventing the spread of infectious diseases continuing to research and develop new vaccines, scientists can stay one step ahead of the pathogens and help protect individuals from serious illness or death.

Should some vaccines be compulsory?

While vaccines are essential tools in preventing the spread of infectious diseases, vaccine trials on humans raise ethical concerns regarding the risk-benefit ratio for participants. Researchers must weigh potential benefits of the vaccine against the risks of adverse reactions and side effects.

Vaccine trials must adhere to strict ethical standards, and participants must provide informed consent before taking part. The participants must be fully informed of the risks and benefits of the vaccine and have the right to withdraw at any time.

Moreover, it's essential to ensure that the vaccine is safe and effective for all individuals, regardless of age, gender, or ethnicity. This requires a significant investment of time, money, and resources to conduct clinical trials and gather data to ensure that the vaccine is safe and effective.

Manufacturers of vaccines must also be held accountable for the quality and safety of their products. Governments must ensure that vaccines are adequately tested, regulated, and monitored to ensure that they meet established safety and efficacy standards before being released to the public.

In conclusion, while vaccines are essential in controlling the spread of infectious diseases, vaccine trials must adhere to strict ethical standards and prioritize the safety and well-being of participants. Researchers and manufacturers ensure are safe, effective to all individuals.

Prioritising who should be vaccinated

When vaccine stocks are running low or when a vaccine is very expensive to manufacture, who should be prioritised for vaccination?

Monetary issues

Monetary issues must also be taken into consideration. Is it right to charge money for vaccinations or should they be free? How will vaccination programs be funded? How is this funding balanced with the need to fund treatments for other diseases?

Vaccines - Key takeaways

Vaccines are a crucial preventative measure against infectious diseases caused by pathogens. They work by introducing a dead or weakened version of the pathogen to the body, which triggers an immune response and the development of memory cells that provide long-term immunity.

There are two types of vaccines: live attenuated vaccines and inactivated vaccines. Live attenuated vaccines contain weakened forms of the pathogen that can still replicate and trigger a stronger immune response, while inactivated vaccines contain dead pathogen that cannot replicate but still trigger an immune response.

Herd immunity is achieved when a large enough percentage of the population has been vaccinated, making it difficult for the pathogen to spread. This is particularly important for protecting vulnerable populations who cannot be vaccinated, those with compromised systems.

However, the use of animals in vaccine testing raises ethical concerns. While animal testing is necessary for ensuring the safety and efficacy of vaccines, it's important to minimize animal suffering and ensure that alternative methods are used whenever possible.

The question of whether vaccination should be mandatory also raises ethical concerns. While mandatory vaccination policies may be necessary to achieve herd immunity and protect public health, they can also infringe on individual autonomy and raise questions around government authority.

Ultimately, the decision to vaccinate should be a personal one based on a careful consideration of the risks and benefits. Governments and health organizations should focus on educating the public about the importance of vaccination and addressing concerns that people may have about vaccines to increase uptake rates and protect public health.

Vaccines

How do vaccines prevent disease?

Vaccines prevent disease in two ways. Vaccines prevent disease on an individual level by immunizing individuals against disease. When a person is vaccinated they are then immune to the disease vaccinated against. Vaccines also prevent disease on a wider community level. If the majority of the population is vaccinated then the spread of disease is stopped and herd immunity is reached. This is when unvaccinated individuals are also protected from disease because enough people have been vaccinated to break the diseases' chain of transmission.

What do vaccines contain?

Vaccines contain antigens from a specific disease that is being vaccinated against. Live attenuated vaccines contain weakened or damaged versions of pathogens, while inactivated vaccines contain whole pathogens that have been killed or subunits of the pathogens, such as proteins.

Why are adjuvants added to vaccines?

Adjuvants are added to vaccines because they promote the uptake of the antigen by the immune system. They help to increase the body's immune response to a vaccine.

What are the ethical issues with vaccines?

In research, questions as to who should research and manufacture vaccines must be raised, as well as what sort of profit they should be able to make from manufacturing vaccines. Vaccines are also often tested on animals in clinical trials, which some see as unethical because animals are unable to consent to testing. Ethical issues arise as to who should be vaccinated and if vaccines should be compulsory - how do you balance the need for personal free will with the need to protect the wider community from disease?

How do vaccines create immunity?

The antigens in vaccines stimulate a primary immune response. Helper T cells stimulate B cells to secrete specific antibodies against the vaccine's antigens. Memory cells are then produced which provide immunity as they deliver a fast secondary response if the pathogen is encountered in the body again.

Join Shiken For FREE

Gumbo Study Buddy

Try Shiken Premium
for Free

14-day free trial. Cancel anytime.
Get Started
Join 20,000+ learners worldwide.
The first 14 days are on us
96% of learners report x2 faster learning
Free hands-on onboarding & support
Cancel Anytime