BPS1101 - Vaccines

Question 1

How is immunity developed?

Answer 1

Immunity is developed after exposure to an illness, when our bodies have found and make copies of antibodies that work to treat the illness.

Question 2

How does immunity work?

Answer 2

After developing immunity to a disease, subsequent exposure produces a faster immune response, killing the infectious microbes before they become large in number and make us sick.

Question 3

How do vaccines contribute to immunity?

Answer 3

Vaccines allow us to develop immunity while skipping over the illness, by inciting an immune response that produces the antibodies that would be necessary to fight off a specific illness, should we be exposed to it in the future.

Question 4

How does immune system memory work?

Answer 4

Immune system memory works by identifying microbes using a large number of random antibodies and receptors, and then making copies of the one that works so that the next time we are exposed to the microbes they can be treated swiftly with the antibodies already present.

Question 5

What is the adaptive immune system?

Answer 5

The adaptive immune system as a system that works well to identify infections and treat them using a selective immune response but takes 2-3 days to produce a maximum immune response.

Question 6

How does the adaptive immune system work?

Answer 6

The adaptive immune system consists of antibodies carried by B cells with each B cell carrying an antibody that recognizes a specific epitope on a specific microbe.

Question 7

How does the body make and store antibodies? How do vaccines take advantage of this?

Answer 7

The body makes many unique antibodies that each stick to a specific epitope and when an infection takes place the body finds an antibody that works and then makes copies of that specific antibody. Vaccines take advantage of this by using genetically modified microbes that have the epitopes present in the real virus minus the virus itself, in order to trigger an immune response that produces the antibodies that would be needed to fight off the actual virus. Most infections only occur once.

Question 8

What happens to B cells during the immune response?

Answer 8

Immune response trigger replication of specific B cells with some B cells becoming memory cells after the infection, so that the next time an exposure to the same virus takes place there is no lag period.

Question 9

What impact do memory cells have on future infections?

Answer 9

Memory cells allow us to skip over the lag period upon future exposure to a virus because we already have antibodies present to treat the virus, before it becomes a full blown infection and we get sick.

Question 10

How do viruses evade our immune system? How does the immune system track them down?

Answer 10

Viruses hide inside of our cells and so the infected cells display fragments of the viral protein on their MHC receptors in order to let the immune system know that they are infected and with what. Helper T cells send this information to killer T cells which upon receiving confirmation from both the helper T cell and the infected cell itself, sends instructions to the infected cell to die, killing the virus along with it.

Question 11

What cells become memory cells?

Answer 11

Both B cells and T cells can become memory cells to fight off future infection

Question 12

How many times do most diseases infect the same person?

Answer 12

Most diseases only infect once

Question 13

What were the effects/symptoms of smallpox?

Answer 13

Smallpox had a 20-40% mortality rate and left 70-80% of survivals disfigured. Symptoms of smallpox included fever and a distinctive rash, especially on the face. It was a debilitating disease that killed large numbers of people before it was eradicated.

Question 14

What was variolation?

Answer 14

Variolation was a practice used in many ancient cultures were people would be deliberately exposed to illnesses that they hadn’t yet caught.

Question 15

How was vaccination discovered? By who?

Answer 15

Vaccination was discovered by Edward Jenner when he observed that milkmaids who worked with cows and caught cowpox did not catch smallpox. He tested out his theory that the cowpox infections were preventing the milkmaids from catching smallpox by inoculating small children with cowpox and then smallpox and then observing that they did not catch smallpox.

Question 16

How did the smallpox vaccination work?

Answer 16

The smallpox vaccination worked by injecting people with cowpox which had a similar enough molecular structure to smallpox to produce the antibodies required to fight off cowpox, while giving the patient only the mild symptoms of cowpox.

Question 17

What was anthrax and what issues did it cause on a larger scale?

Answer 17

Anthrax was a disease that affected livestock, causing them to die which was having adverse economic effects

Question 18

What did Louis Pasteur do to fight Anthrax?

Answer 18

Louis Pasteur discovered that he could create a weakened version of anthrax to be used in vaccinating by attenuating (heating) the virus which would cause only mild infection but still produce the necessary antibodies.

Question 19

What was the issue with the Anthrax vaccine? How was this resolved?

Answer 19

The issue with the anthrax vaccine was that because the virus itself was weakened, the immune response was also weakened and so it wasn’t producing the desired amount of antibodies. This was resolved using booster shots of the vaccine that served the purpose of increasing immune response.

Question 20

How do attenuated vaccines work? What are the potential effects?

Answer 20

Attenuated vaccines are vaccines that contain disease microbes that have been treated with heat or chemicals. The potential risk with the use of these vaccines is that because the virus is present you could catch the disease but this is very rare and unlikely unless you have a seriously weakened immune system?

Question 21

What is paralytic polio? What was the biggest impact of this form and how was it treated?

Answer 21

Paralytic polio accounts for approximately 1% of polio cases and involves paralysis of all muscles in the body including those that expand and contract the lungs, leading to patients suffering from this type of polio suffocating to death. From the 1950s patients presenting with paralytic polio were treated using iron-lung machines that breathed for them, with several iron-lung users still being alive today.

Question 22

What was the first polio vaccine and how did it work?

Answer 22

The first vaccine to treat polio was the Salk vaccine ,discovered in the early 1950s by Jonas Salk, which injected a dead virus and required a booster shot. The largest ever clinical trial took place in 1954 and the vaccine was discovered to be very safe and very effective, and was subsequently distributed to 1.4 million school children.

Question 23

What issue stemmed from the use of the Salk vaccine?

Answer 23

One batch of the vaccine produced by Cutter Laboratories had not undergone the proper testing and was discovered to contain the live virus but upon discovering this the company did not report to the government and simply sold the treatments as planned, leading to 170 cases of paralytic polio and 11 deaths.

Question 24

What was the second polio vaccine and how did it work?

Answer 24

Shortly after the development of the Salk vaccine the Sabin vaccine, which used an attenuated virus and was administered orally was developed. The Sabin vaccine did not require any booster shots and was adopted by most countries but did pose a 1 in 1 million risk of giving the patient polio.

Question 25

What impact did the polio vaccines have on the spread of polio? What happened when people stopped vaccinating?

Answer 25

After the adaptation of the Sabin vaccine by most countries by 2003 there were fewer than 300 cases worldwide. Due to political issues, in countries where people who were illegally trying to seize power denounced vaccines as western propaganda the number of cases rebounded to 1600, leading to the starting of the global eradication initiative in 2009. Cases of polio have then dropped by 99% since 2009

Question 26

What is the typical influenza cycle?

Answer 26

Influenza causes seasonal colds that typically infect 5-15% of population with a new virus forming ever year, spreading from the beginning of the flue season in October, with vaccines beginning development in June and being rolled out in November

Question 27

What are some misconceptions about flu vaccinations and what causes them? Why is it still important to get vaccinated against the flu?

Answer 27

A general misconception about the flu vaccine is that it doesn’t actually prevent people from catching the flu due to the number of people who get vaccinated but still catch it every year. This is because of the fact that the vaccines are rolled out after the flu season begins and also take 21 days to produce full immunity, which produces a period of time for both vaccinated and non-vaccinated people to catch it regardless. It is still important to get vaccinated against the flu because the vaccination can not only protect you from other subtypes of the virus and you never know when a particular flu strain will recirculate.

Question 28

What are the impacts of vaccines on diseases as a whole? How does this impact people’s ideas about vaccination?

Answer 28

Several diseases have been eradicated and many are close to eradication thanks to vaccination. As diseases are eradicated the number of adverse events relating to the disease decrease in number, making them stand out more when they do happen , sometime leading to people focusing more on the number of people who do get a disease versus the number of people who don’t get the disease.

Question 29

What are the catalysts for anti-vaccine sentiment?

Answer 29

Anti-vaccine sentiment is based around successful propaganda with a lot of modern anti vaccine activists fixating on the idea that vaccines can cause autism. Studies have proved that this is untrue but this theory stems from the fact that children with autism are often diagnosed around age 2 which is when they typically receive several of their childhood vaccinations. This baseless rumour was spread by a bogus study done by Wakefield et. al and he was subsequently stripped of his medical license.

Question 30

What are the impacts of anti vaccine sentiments?

Answer 30

Anti vaccine sentiments lower vaccination rates which increase infection rates in the population?

Question 31

Why is it important for people to get vaccinated both in general as well as when a country is disease free?

Answer 31

Generally, it is important for people to get vaccinated in order to maintain her immunity, which refers to the need for a certain proportion of the population to be vaccinated in order to prevent the circulation of a disease. It is important for people to get vaccinated even when a country is disease free because if people stop getting vaccinated it is very easy in this day and age for a disease to spread from one part of the world to another. When countries preemptively stop vaccinating against illnesses that have not been completely eradicated the diseases can easily become recirculated in a short period of time.

Question 32

What happened in Japan when the government discontinued Pertussis (Whooping Cough) vaccination?

Answer 32

After lowering the number of cases to 394 in 1948 the Japanese government discontinued vaccination against Pertussis leading to the number of cases rising to 13,000 by 1978, with 41 deaths.

Question 33

Are there vaccines to prevent cancer? What are they and how were they disocvered?

Answer 33

Despite originally being though of as a disease to do with “nervous irritability” in women, it was discovered that cervical cancer was a viral disease that only occurred in sexually active women, being linked to HPV in the 1970s. There are more than 200 types of HPV virus but only two that cause cancer (cervical and testicular). Gardasil, the vaccine used to prevent HPV, is made up from protein fragments and presents no risk of giving people HPV because it doesn’t contain a full virus.

Question 34

What concerns have been raised about the Gardasil vaccine?

Answer 34

Guillian-Barre syndrome can take place after Gardasil vaccination but these instances are very rare, with there having been 69 reported cases of associated GBS out of 8.6 million vaccinations, with 12 of these resulting in paralysis. Another issue raised with this vaccination, is the political belief that it encourages sexual activity which has been disproven.