How Vaccines Can Be Used To Fight Outbreaks

How a vaccine for a newly discovered virus is made, what determines if a vaccine is effective or not, and how many people need to be vaccinated to get herd immunity. I include how the trajectory of an outbreak would change if more people got vaccinated.
Anay Shroff
Grade 6


An outbreak is when the number of cases for a disease suddenly rises.

 An outbreak may occur in a big or small area. It may stay for a few days, weeks, or years.

   A vaccine is a thing that makes the Immune system produce antibodies by making it think that our body are exposed to the disease; it works by putting in a harmless or dead version of the virus into the immune system.

My question is how an effective vaccine can stop an outbreak so that an outbreak doesn’t last for several years?


Stopping a viral or bacterial outbreak can’t be done by luck. There are public health tools that are required to help. Vaccines are considered as one of the best health tools in the world, which is why if there is a new disease Scientists rush to make a good and effective vaccine for it. There is often the most rush for a vaccine on a virus or bacteria that can infect more people in less time.

In my opinion if enough people achieve herd immunity then outbreaks for the disease can stop or the disease can be eradicated There are so many ways to achieve herd immunity for example, taking hygiene precautions, most people get infected with the disease, but if the disease is deadly and it is easily transmittable like COVID-19, vaccines are the best and effective health tool to stop outbreaks



Viruses are microorganisms that we can only see with a microscope, and some of them are harmful. They can affect health seriously and they can even cause for death. To stop viruses there are some special public health tools required. One of the public health tools are vaccines. Vaccines are things that make our immune system produce antibodies for a virus, by tricking it to think that the version of the virus inserted by the vaccine(either harmless or dead) is harmful so the immune system gives an immune response. Vaccines save many people’s lives from harmful viruses every year.  Some examples of harmful viruses are COVID-19, Ebola, Zika virus, and the flu.

Viruses have caused pandemics for millennia, which have cause hundreds of millions of deaths. There are many viruses such as the bubonic plague(also known as Black Death), and smallpox which have killed millions of people worldwide. The 1918 Spanish flu pandemic has also killed 40-70 million people worldwide. There have also been other flu epidemics and pandemics in 1968, and 2009. These have also caused a number of deaths, but they have been resolved more quickly because of vaccines already being there but those vaccines just needed to be tweaked a bit.

Another example is SARS (Severe Acute Respiratory Syndrome) which is caused by a coronavirus. It spread rapidly throughout Asia and Europe, then reached north, and south America. It resulted in a total of 8098 cases and 774 deaths. Since 2004 there have been no reports of SARS, but several vaccines for SARS are in their pre-clinical trial stage(as per 2018) to prepare just in case SARS comes again.

All of these diseases that have caused pandemics or epidemics are considered either emerging infectious diseases(diseases that have never appeared before) or re –emerging infectious diseases( diseases that have been recognized but are appearing in a different form, in a different location. But there is one thing in common with all diseases, which is that they are dangerous. Luckily we don’t have to worry for a re-emerging infectious disease, as much as we have to worry for an emerging infectious disease, because we already have a vaccine for a re-emerging infectious disease it is just that we need to tweak it a bit.

In the old times, whenever a disease struck people were very worried because there was nothing that they could do to stop it. Luckily now we don’t have to worry as much because we have vaccines, and we can make them for a new disease even if it takes time. The thing we have to worry about the least because of vaccines is that the disease will last for decades, or centuries. 





So many people get infected and some of them die because of a novel disease. A novel virus is a virus that has never been discovered before.  After a novel virus starts infecting people, biotechnology companies around the world start rushing to make a good and effective vaccine for the new novel virus. If it is a novel virus, then we don’t have a vaccine for it because it is a brand new disease. Several months after the disease has been found, we see major outbreaks in countries worldwide which is why biotechnology companies race to develop a safe and effective vaccine for that virus. Without a proper vaccine and no health precautions (for example closures, masks, physical distancing, proper hygiene), an outbreak can cause severe problems around the world and hospitals around the world would fill up very quickly. With all of that the number of people immune would also rise as the number of infected people rises since if a person gets infected, after the virus goes away the person also becomes immune, but with deadly viruses we need vaccine protection early to save human beings.



Normally vaccines undergo many stages before they are approved for use.

  • The first step for a normal vaccine is pre-clinical trial, there they check if the animals they administer the vaccine to develop antibodies.
  • The next step is phase 1 clinical trials, there they give the vaccine to 25-50 healthy adults to see if it is safe or not (each adult is monitored individually).
  • The next phase is phase 2 clinical trials, it involves hundreds of people to find out the correct dosage to give, and if it develops an immune response or not.
  • Then in the phase 3 clinical trial the vaccine is given to thousands of people to assess if it protects humans or not and if it is safe to use.
  • If it does protect people from the disease then it is checked by regulators for effectiveness, safety and quality of the vaccine and it is checked by independent policy makers (Like Centers for Disease Control, Health Canada) to determine the best way to use it. If the vaccine meets the standards the vaccine can then be authorized for use, and it is ready for licensing and registration, normally this whole process takes 5-10 years.

In the case of a recent deadly virus like COVID-19 where the vaccine is needed urgently, some of the phases are running parallel, and the research team can send a request for temporary authorization from the regulatory body and an emergency use listing from WHO. This authorization from WHO is only given if the vaccine meets strict safety and effectiveness standards. For the COVID vaccine once the vaccine is being used it is continuously monitored by health officials throughout its use. Even though some of the phases run parallel there is no lack of safety throughout the process of the development of the vaccine.




Vaccines work by tricking our immune system into thinking that it has been attacked by the infectious disease that we want to inoculate against. Vaccines are mainly made in 2 different ways.

1. The first way uses a harmless version of the real virus. When the vaccine is given to a person, the harmless version has what is called a vector virus. That vector virus produces the spike protein found on the surface the vaccine is trying to prevent, because of that protein our body makes antibodies which can grab on to that protein. Through this process, the body is able to build a strong immune response against the spike protein without exposing you to the virus that causes the disease. One example of this is the Oxford-AstraZeneca COVID-19 vaccine.

2.The second way is using RNA or DNA to make the protein found on the surface of the virus the vaccine is trying to prevent. The RNA or DNA teaches our cells how to make the protein that the virus has on its surface. After our cells make that protein the immune system spots it and makes antibodies which can grab on to the protein so that in case the person gets infected the antibodies can be produced right away and they can hold on to the virus while the other cells kill it. Some examples are the Pfizer, and Moderna COVID-19 vaccine.




Some vaccines need to be taken only once in a lifetime, while other vaccines need to be taken at regular intervals. Some examples of vaccines that are needed once in a lifetime like the measles vaccine. Some other vaccines need to be taken at regular intervals like the Mumps, and Rubella vaccine. Some vaccines like the COVID-19 vaccine need a booster dose for you to be fully protected against the disease. Some vaccines are given 3 to 4 ties at a few month intervals when you are a baby and then not needed to be given again after grownups.





It is not only important for the vaccine to have efficacy, it is also important for the maximum amount of people to take the vaccine. That can be done in many ways but the most effective would be the government advising the public of the safety of the vaccine. To do that the government can do various things like advertising, handing out flyers door to door, going door to door with vaccine registration sheets to encourage people to take the vaccine. The government can also make advertisements on TV and social media about how the vaccine is safe and what steps they take to ensure the vaccine is safe. Here is some information I found on Health Canada website about vaccine safety.





There are 6 steps for vaccine safety in Canada.

  • The first step is development, the research and development takes place then preclinical trials take place. After that the three phase clinical trials on people take place.
  • The second step is testing and approval, in this step Health Canada examines the results of the clinical trials to see if the vaccine works and if it is safe or not.
  • The third step is recommendations, in this step the NACI (National Advisory Committee on Immunization reviews the vaccine and determines the best use of the vaccine.
  •  The fourth step is manufacturing and transporting, in this step the manufacturer makes the vaccine and tests each batch to ensure the quality and safety. Then the Vaccines are packaged and labelled and then carefully stored for transportation. Then they transport the vaccine to the health center under the controlled temperature which the vaccine requires.
  • The fifth step is vaccination; in this step licenced health professionals administer the vaccine and record details on the patient’s records. Provincial/ territorial and federal officials meet to discuss the progress of the vaccination.
  • The sixth and final step is monitoring, in this step the vaccine is monitored for any deadly side effects as long as it is in use in Canada.


 ( <--- this is where I got the information from)



Vaccine distribution is a key factor for effective rollout of the vaccine program and they can be distributed based on priority factors like people’s age, work area and health conditions.


No vaccine works perfectly; a vaccine’s effectiveness is measured by the number of people who get immune to the disease because of the vaccine. For example for the measles vaccine 98% of the people who take the vaccine get successfully immune to the measles disease. Even when the vaccine does have effectiveness vaccines don’t take effect right away, it usually takes a few days to a few weeks for the body to build the initial immune response and remember the virus to help fight it next time.


The number of people required to be immune in order to achieve her immunity varies with each disease. For example the measles requires about 95% of the population to be vaccinated to achieve herd immunity, and the 5% remaining population is protected because of the virus having a hard time finding people to infect. For the Polio the percent of population required to be vaccinated to get herd immunity is 80% and the polio has been almost eradicated all over the worlds except a few countries.



Right now as the COVID-19 disease spreads around the world, strong vaccination efforts are required to achieve herd immunity. As the COVID-19 vaccines are coming out around the world, health care officials are wondering how many people will need to take the COVID-19 vaccine in order to achieve herd immunity. As of right now health care officials are saying the 70-90% of the world’s population will need to take the new COVID-19 vaccine in order to gain herd immunity. This number might change but as of now this is the goal that WHO has to vaccinate 70-90% of the world’s population. As per the data from Israel where 99.88% of the population has been vaccinated the cases have drastically dropped.

COVAX is a program made by the World Health Organization which makes sure that all the countries around the world get COVID-19 vaccines. COVAX works by having countries like Canada and the United States which can afford COVID-19 vaccines give spare vaccines to countries that can’t afford to buy COVID-19 vaccine so that people get immunized faster and people around the world obtain herd immunity faster.




                Measles is an extremely contagious and very serious disease which is caused by a virus. It is caused by a virus that is in the paramyxovirus family and it is normally passed through the air. If a person gets the Measles the persons respiratory tract, and then spreads through the body. Measles has only been found in humans and not animals unlike COVID-19 which has been detected in animals.    

Before the measles vaccine got introduced in 1963, large scale epidemics happened approximately every two to three years and resulted in about 2.6 million deaths each year. Most Measles deaths have happened in children under age of 5 and in 2018 even though there was a safe and cost efficient vaccine for the Measles 140,000 deaths occurred globally. Faster Immunization had a major impact on reducing measles deaths, because of Measles vaccination there has been a 73% drop in Measles related death from 2000-2018. During 2000-2018 the Measles vaccine prevented about 23.2 million deaths which make the Measles vaccines one of the best in public health.


Since 1918 the world has had about 4 pandemics for influenza only, and it has caused millions of deaths around the world including Canada.

  • In 1918 there was the first pandemic of the influenza happened, it was cause by the H1N1 virus
  • In 1957(1957-1958) there was a flu pandemic, it was caused by the H2N2 virus
  • In 1968 an influenza pandemic was caused by the H3N2 virus
  • In 2009 a novel version of the H1N1 virus caused another influenza pandemic


World got the vaccine for Influenza in the early 1940s, and it has widely circulated since the time of WW2.


  • Millions of Canadians have been infected with the seasonal influenza each year
  • Around 12,000 people in Canada are hospitalized each year because of influenza, and there are around 3,500 deaths each year in Canada because of the influenza virus


Canada’s goal is to vaccinate 80% of people at high risk to reduce Influenza related deaths.

In the 2019-2020 season:

  • 44% of Canadian adults with chronic medical conditions took the influenza vaccine.
  • 70% of seniors took the influenza vaccine

This still falls short of the Canadian influenza vaccination goal, but because of this vaccination our effort to stop outbreaks is successful.




In the 2017-2018,2018-2019,and 2019-2020 season


Seasonal flu vaccination coverage for all adults (18+)

Flu season

Percent vaccinated (%)







Seasonal flu vaccination coverage for age 18-64 without chronic medical conditions

Flu season

Percent vaccinated (%)







Seasonal flu vaccination coverage for age 18-64 with chronic medical conditions

Flu season

Percent vaccinated (%)







Seasonal flu vaccination coverage for seniors (65+)

Flu season

Percent vaccinated (%)













COVID-19 INFECTION DATA (as of March 7 2021)

(This data is from John Hopkins University COVID tracker)

  • Around the world 116,712,556 total cases of COVID-19
  • In Canada there are 891,792 total cases of COVID-19


COVID-19 VACCINATION DATA (as of March 6 2021)

  • 3.85% of the world’s population has received the COVID-19 vaccine
  • In Israel 99.88% of the population has received the COVID-19 vaccine
  • In Canada 6.17% of the population has received the COVID-19 population

Canada’s goal is to give all people above the age of 16 the first dose of the COVID-19 vaccine by the end of June







As I said in my hypothesis and described in my research, achieving herd immunity is essential to stopping outbreaks, and vaccines play a huge part in the stopping of outbreaks. It is not only important to have an effective vaccine, but besides that other important factors like timely mass production of the vaccine, proper distribution of the vaccine, and public awareness about the safe vaccine so that enough people(70-95% of the population depending on the disease) get the vaccine to stop outbreaks and eventually eradicate the disease.

Unfortunately we won’t have a vaccine readily available for a virus that is novel (like COVID-19), but outbreaks can be controlled with the proper use of other public health tools like wearing masks, proper hand hygiene, and limited gatherings if the disease is very contagious, and staying healthy by exercising and eating healthy until research scientist develop a new and effective vaccine, and the vaccine gets distributed.  

From the past experience an effective vaccine is always useful with the help of organizations like W.H.O. and health care volunteers from around the world to not only stop outbreaks but to also eradicate the disease like in the case of measles and partially in the case of polio. To stop a pandemic collective coordinated efforts from around the world are required.



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  • Vaccines for Pandemic Threats. History of Vaccines. (2018, January 10).


  • World Health Organization. (2019, November 27). Measles – Global situation. World Health Organization.


  • World Health Organization. COVID-19 vaccines. World Health Organization.


  • Canada, H. (2021, January 8). Government of Canada.


  • Canada, H. (2021, February 26). Government of Canada. What you should know: AstraZeneca COVID-19 vaccine -


  • McCallum, K. (2020, December 30). Herd Immunity: How Many People Need to Get the COVID-19 Vaccine? Houston Methodist on Health.


  • Government of Canada, S. C. (2015, November 27). Health at a Glance. Flu vaccination rates in Canada.


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  • Centers for Disease Control and Prevention. (2018, March 21). History of 1918 Flu Pandemic. Centers for Disease Control and Prevention.


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  • organization, world health. (2020, December 31). Coronavirus disease (COVID-19): Herd immunity, lockdowns and COVID-19. World Health Organization.





Firstly, I would like to thank the CYSF team to promote the young scientist and give students like me an opportunity to do this type of project. I would also like to thank my school, school principal, and science teachers who provided guidance to me with this project, and who encouraged me to take part in this type of project. I would also like to than all the research scientist in the world who inspired kids like me to do this type of research. I would also like to thank all levels of government for encouraging people to take immunizations, and I would like to thank UN organisations, like WHO and UNICEF who work towards immunization programs world-wide and health care workers and volunteers around the world.  I would also like to thank my parents who helped me throughout the process of making my projects, and I would like to thank Mother Nature.