10.1371/journal.pone.0176845 MATHguide.com.

10.1371/journal.pone.0176845 MATHguide.com.

Vyas, KidsHealth, The Nemours Foundation, July 2017, kidshealth.org/en/parents/chicken-pox.html.

  • “Chickenpox | Monitoring Vaccine Impact | Varicella | CDC.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, www.cdc.gov/chickenpox/surveillance/monitoring-varicella.html.
  • “Chickenpox (Varicella).” History of Vaccines, www.historyofvaccines.org/index.php/content/articles/chickenpox-varicella.
  • “Chickenpox.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Nov. 2018, www.mayoclinic.org/diseases-conditions/chickenpox/symptoms-causes/syc-20351282.
  • “Chicken Pox (Varicella Zoster Virus) Infection Information.” MyVMC, 31 May 2018, www.myvmc.com/diseases/chicken-pox-varicella-zoster-virus/.
  • “Epidemiology and Prevention of Vaccine-Preventable Diseases.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 11 Aug. 2015, www.cdc.gov/vaccines/pubs/pinkbook/varicella.html.
  • “Facts about Chickenpox.” US National Library of Medicine, Pediatric Children’s Health, Sept. 2005, www.ncbi.nlm.nih.gov/pmc/articles/PMC2722564/.
  • Facts About Chickenpox and Shingles for Adults. National Foundation for Infectious Diseases, Aug. 2009, www.nfid.org/publications/factsheets/varicellaadult.pdf.
  • “History of Anti-Vaccination Movements.” History of Vaccines, www.historyofvaccines.org/content/articles/history-anti-vaccination-movements.
  • Marangi L, Mirinaviciute G, Flem E, Scalia Tomba G, Guzzetta G, Freiesleben de Blasio B, et al.
    (2017) The natural history of varicella zoster virus infection in Norway: Further insights on exogenous boosting and progressive immunity to herpes zoster. PLoS ONE 12(5): e0176845. https://doi.org/10.1371/journal.pone.0176845
  • MATHguide.com. “Geometric Sequences and Series.” MATHguide Is the Source for Interactive Mathematics for Students, Parents and Teachers Called MATHguide, www.mathguide.com/lessons/SequenceGeometric.html.
  • “R Nought and Vaccine Coverage.” Khan Academy, Khan Academy, www.khanacademy.org/science/health-and-medicine/current-issues-in-health-and-medicine/ebola-outbreak/v/r-nought-and-vaccine-coverage.
  • “Reported Cases and Deaths from Vaccine Preventable Diseases, United States, 1950-2013.” Centers for Disease Control and Prevention Epidemiology and Prevention of Vaccine-Preventable Diseases, 13th Edition , Apr. 2015, vaccines.procon.org/sourcefiles/cdc-reported-cases-and-deaths-from-vaccine-preventable-diseases.pdf.
  • “The Mathematics of Diseases.” The Mathematics of Diseases, 25 July 2018, plus.maths.org/content/mathematics-diseases.
  • “Varicella (Chickenpox): Questions and Answers.” Vaccine Information, Immunization Action Coalition, www.immunize.org/catg.d/p4202.pdf.
  • Wharton M. The epidemiology of varicella-zoster virus infectionsExternal. Infect Dis Clin N Amer. 1996;10:571–81.
  • “ What Is Herd Immunity?” PBS, Public Broadcasting Service, www.pbs.org/wgbh/nova/article/herd-immunity/.
  • a3 =(1)53–1

    → (1) 25 = 25

    a4 =(1)54–1

    = 125

    a5=(1)55–1

    = 625

    a6=(1)56–1

    = 3125

    Generation

    Infected per generation

    Total infected

    1

    1

    1

    2

    5

    6

    3

    25

    31

    4

    125

    156

    5

    625

    781

    6

    3125

    3906

    Based off of our equation, it would take just 6 generations to infect the entire school. This illustrates the dire significance of vaccinations to grant immunity.

    Herd Immunity:
     Herd immunity is a large factor in the infection rates within a population. It dictates that “for each person that is vaccinated the risk of infection for the rest of the community decreases.”[9] In other words, Herd immunity is when the recovered, who are immune, outnumber the healthy susceptible, leading to little chance of creating an epidemic. Vaccination serves as somewhat of a bridge from the susceptible to the recovered, in that the in-patient never goes through the disease. Vaccination is very important to society because it creates herd immunity superficially; the amount of people that are infected or recovered are vastly smaller than a naturally-occurring setup. The Herd Immunity Threshold is the portion of the population that needs to be immune to control transmission of a disease. The Diekmann and Heesterbeek equation for Herd Immunity Threshold is

    Ht = BR–1BR

    = 1- 1BR

    This equation can help us uncover the percentage of people needed to be immune to protect the population. As previously stated, the average range secondary transmissions from one person is 5 (R0 = 5.0) so plugging that into the equation would give us

    1 –  1R0

    = 1 – ( 15

    ) = (45

    )

    Therefore, 80% regarding the population needs to be either immune vaccinated in a totally susceptible environment in order to stop the spread of varicella. [10]

    As more and more people are vaccinated, the herd immunity threshold also
    https://medium.com/@vladimirtrofimov049/best-3-biology-essay-samples-926566c2efb4increases. By decreasing the number of susceptible individuals, the herd immunity threshold decreases.

    Figure C. Visual representation of Herd Immunity taking effect in a population.[11]

     

    Case Trends:

     As vaccinations have become more and more standardized in society and widely implemented, we have experienced a decrease in not only varicella rates but many other diseases as well. Using data from the Morbidity and Mortality Weekly Reports (MMWR), I was able to create a graph.

    Based off of this graph and the data points, I used my calculator to find an equation for the Cases line of best fit.

    y=6.2458E 97 (.89838)x

    The graph was very eye-opening because it really pointed out the drastic downward trend of cases throughout the last few decades. It seemingly will hit zero soon, however that is improbable due to human error; many people do not have access to the varicella vaccine or choose not to partake in it. Since the origins of vaccination, some people have opposed the practice on the grounds that it is not “natural”, or may contain harmful chemicals. In the 1970s, people began to falsely believe that the vaccinations could actually do harm, and blamed cases of autism on the vaccinations. [12] Since 2001, the percentage of people who choose not to vaccinate has quadrupled.

     

    Conclusion:

     I went into this IA with minimal information on the dynamics of epidemiology, and furthermore the importance of vaccination. Every year when I get my shots, I think little of it, but this report highlighted just how much they matter. I regret having the limited scope of just the United State’s data, because I know that in other countries it would vary vastly due to cultural views on anti-vaccination, as well as simply limited access to health care. I felt very privileged and humbled that I live in a place where these options are available to me. If I were to further my research, I would extend my perspective globally, and compare with other countries. Additionally, if there was sufficient data available then I could compare my data with epidemics regarding the past, particularly ones which wiped out populations.

    I have an interest in the healthcare field, particularly in research; as time goes by,  I believe that medicine will advance to further eradicate disease and viruses.

     

     

     

     

     

    Appendix:

    Bibliography

    • “Chickenpox (for Parents).” Edited by Shayan T. Vyas, KidsHealth, The Nemours Foundation, July 2017, kidshealth.org/en/parents/chicken-pox.html.
    • “Chickenpox | Monitoring Vaccine Impact | Varicella | CDC.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, www.cdc.gov/chickenpox/surveillance/monitoring-varicella.html.
    • “Chickenpox (Varicella).” History of Vaccines, www.historyofvaccines.org/index.php/content/articles/chickenpox-varicella.
    • “Chickenpox.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Nov. 2018, www.mayoclinic.org/diseases-conditions/chickenpox/symptoms-causes/syc-20351282.
    • “Chicken Pox (Varicella Zoster Virus) Infection Information.” MyVMC, 31 May 2018, www.myvmc.com/diseases/chicken-pox-varicella-zoster-virus/.
    • “Epidemiology and Prevention of Vaccine-Preventable Diseases.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 11 Aug. 2015, www.cdc.gov/vaccines/pubs/pinkbook/varicella.html.
    • “Facts about Chickenpox.” US National Library of Medicine, Pediatric Children’s Health, Sept. 2005, www.ncbi.nlm.nih.gov/pmc/articles/PMC2722564/.
    • Facts About Chickenpox and Shingles for Adults. National Foundation for Infectious Diseases, Aug. 2009, www.nfid.org/publications/factsheets/varicellaadult.pdf.
    • “History of Anti-Vaccination Movements.” History of Vaccines, www.historyofvaccines.org/content/articles/history-anti-vaccination-movements.
    • Marangi L, Mirinaviciute G, Flem E, Scalia Tomba G, Guzzetta G, Freiesleben de Blasio B, et al.
      (2017) The natural history of varicella zoster virus infection in Norway: Further insights on exogenous boosting and progressive immunity to herpes zoster. PLoS ONE 12(5): e0176845. https://doi.org/10.1371/journal.pone.0176845
    • MATHguide.com. “Geometric Sequences and Series.” MATHguide Is the Source for Interactive Mathematics for Students, Parents and Teachers Called MATHguide, www.mathguide.com/lessons/SequenceGeometric.html.
    • “R Nought and Vaccine Coverage.” Khan Academy, Khan Academy, www.khanacademy.org/science/health-and-medicine/current-issues-in-health-and-medicine/ebola-outbreak/v/r-nought-and-vaccine-coverage.
    • “Reported Cases and Deaths from Vaccine Preventable Diseases, United States, 1950-2013.” Centers for Disease Control and Prevention Epidemiology and Prevention of Vaccine-Preventable Diseases, 13th Edition , Apr. 2015, vaccines.procon.org/sourcefiles/cdc-reported-cases-and-deaths-from-vaccine-preventable-diseases.pdf.
    • “The Mathematics of Diseases.” The Mathematics of Diseases, 25 July 2018, plus.maths.org/content/mathematics-diseases.
    • “Varicella (Chickenpox): Questions and Answers.” Vaccine Information, Immunization Action Coalition, www.immunize.org/catg.d/p4202.pdf.
    • Wharton M. The epidemiology of varicella-zoster virus infectionsExternal. Infect Dis Clin N Amer. 1996;10:571–81.
    • “ What Is Herd Immunity?” PBS, Public Broadcasting Service, www.pbs.org/wgbh/nova/article/herd-immunity/.

    → (1) 25 = 25

    a4 =(1)54–1

    = 125

    a5=(1)55–1

    = 625

    a6=(1)56–1

    = 3125

    Generation

    Infected per generation

    Total infected

    1

    1

    1

    2

    5

    6

    3

    25

    31

    4

    125

    156

    5

    625

    781

    6

    3125

    3906

    Based off of our equation, it would take just 6 generations to infect the entire school. This illustrates the dire significance of vaccinations to grant immunity.

    Herd Immunity:
     Herd immunity is a large factor in the infection rates within a population. It dictates that “for each person that is vaccinated the risk of infection for the rest of the community decreases.”[9] In other words, Herd immunity is when the recovered, who are immune, outnumber the healthy susceptible, leading to little chance of creating an epidemic. Vaccination serves as somewhat of a bridge from the susceptible to the recovered, in that the in-patient never goes through the disease. Vaccination is very important to society because it creates herd immunity superficially; the amount of people that are infected or recovered are vastly smaller than a naturally-occurring setup. The Herd Immunity Threshold is the portion of the population that needs to be immune to control transmission of a disease. The Diekmann and Heesterbeek equation for Herd Immunity Threshold is

    Ht = BR–1BR

    = 1- 1BR

    This equation can help us uncover the percentage of people needed to be immune to protect the population. As previously stated, the average range secondary transmissions from one person is 5 (R0 = 5.0) so plugging that into the equation would give us

    1 –  1R0

    = 1 – ( 15

    ) = (45

    )

    Therefore, 80% regarding the population needs to be either immune vaccinated in a totally susceptible environment in order to stop the spread of varicella. [10]

    As more and more people are vaccinated, the herd immunity threshold also
    increases. By decreasing the number of susceptible individuals, the herd immunity threshold decreases.

    Figure C. Visual representation of Herd Immunity taking effect in a population.[11]

     

    Case Trends:

     As vaccinations have become more and more standardized in society and widely implemented, we have experienced a decrease in not only varicella rates but many other diseases as well. Using data from the Morbidity and Mortality Weekly Reports (MMWR), I was able to create a graph.

    Based off of this graph and the data points, I used my calculator to find an equation for the Cases line of best fit.

    y=6.2458E 97 (.89838)x

    The graph was very eye-opening because it really pointed out the drastic downward trend of cases throughout the last few decades. It seemingly will hit zero soon, however that is improbable due to human error; many people do not have access to the varicella vaccine or choose not to partake in it. Since the origins of vaccination, some people have opposed the practice on the grounds that it is not “natural”, or may contain harmful chemicals. In the 1970s, people began to falsely believe that the vaccinations could actually do harm, and blamed cases of autism on the vaccinations. [12] Since 2001, the percentage of people who choose not to vaccinate has quadrupled.

     

    Conclusion:

     I went into this IA with minimal information on the dynamics of epidemiology, and furthermore the importance of vaccination. Every year when I get my shots, I think little of it, but this report highlighted just how much they matter. I regret having the limited scope of just the United State’s data, because I know that in other countries it would vary vastly due to cultural views on anti-vaccination, as well as simply limited access to health care. I felt very privileged and humbled that I live in a place where these options are available to me. If I were to further my research, I would extend my perspective globally, and compare with other countries. Additionally, if there was sufficient data available then I could compare my data with epidemics regarding the past, particularly ones which wiped out populations.

    I have an interest in the healthcare field, particularly in research; as time goes by,  I believe that medicine will advance to further eradicate disease and viruses.

     

     

     

     

     

    Appendix:

    Bibliography

    • “Chickenpox (for Parents).” Edited by Shayan T. Vyas, KidsHealth, The Nemours Foundation, July 2017, kidshealth.org/en/parents/chicken-pox.html.
    • “Chickenpox | Monitoring Vaccine Impact | Varicella | CDC.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, www.cdc.gov/chickenpox/surveillance/monitoring-varicella.html.
    • “Chickenpox (Varicella).” History of Vaccines, www.historyofvaccines.org/index.php/content/articles/chickenpox-varicella.
    • “Chickenpox.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Nov. 2018, www.mayoclinic.org/diseases-conditions/chickenpox/symptoms-causes/syc-20351282.
    • “Chicken Pox (Varicella Zoster Virus) Infection Information.” MyVMC, 31 May 2018, www.myvmc.com/diseases/chicken-pox-varicella-zoster-virus/.
    • “Epidemiology and Prevention of Vaccine-Preventable Diseases.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 11 Aug. 2015, www.cdc.gov/vaccines/pubs/pinkbook/varicella.html.
    • “Facts about Chickenpox.” US National Library of Medicine, Pediatric Children’s Health, Sept. 2005, www.ncbi.nlm.nih.gov/pmc/articles/PMC2722564/.
    • Facts About Chickenpox and Shingles for Adults. National Foundation for Infectious Diseases, Aug. 2009, www.nfid.org/publications/factsheets/varicellaadult.pdf.
    • “History of Anti-Vaccination Movements.” History of Vaccines, www.historyofvaccines.org/content/articles/history-anti-vaccination-movements.
    • Marangi L, Mirinaviciute G, Flem E, Scalia Tomba G, Guzzetta G, Freiesleben de Blasio B, et al.
      (2017) The natural history of varicella zoster virus infection in Norway: Further insights on exogenous boosting and progressive immunity to herpes zoster. PLoS ONE 12(5): e0176845. https://doi.org/10.1371/journal.pone.0176845
    • MATHguide.com. “Geometric Sequences and Series.” MATHguide Is the Source for Interactive Mathematics for Students, Parents and Teachers Called MATHguide, www.mathguide.com/lessons/SequenceGeometric.html.
    • “R Nought and Vaccine Coverage.” Khan Academy, Khan Academy, www.khanacademy.org/science/health-and-medicine/current-issues-in-health-and-medicine/ebola-outbreak/v/r-nought-and-vaccine-coverage.
    • “Reported Cases and Deaths from Vaccine Preventable Diseases, United States, 1950-2013.” Centers for Disease Control and Prevention Epidemiology and Prevention of Vaccine-Preventable Diseases, 13th Edition , Apr. 2015, vaccines.procon.org/sourcefiles/cdc-reported-cases-and-deaths-from-vaccine-preventable-diseases.pdf.
    • “The Mathematics of Diseases.” The Mathematics of Diseases, 25 July 2018, plus.maths.org/content/mathematics-diseases.
    • “Varicella (Chickenpox): Questions and Answers.” Vaccine Information, Immunization Action Coalition, www.immunize.org/catg.d/p4202.pdf.
    • Wharton M. The epidemiology of varicella-zoster virus infectionsExternal. Infect Dis Clin N Amer. 1996;10:571–81.
    • “ What Is Herd Immunity?” PBS, Public Broadcasting Service, www.pbs.org/wgbh/nova/article/herd-immunity/.

    a4 =(1)54–1

    = 125

    a5=(1)55–1

    = 625

    a6=(1)56–1

    = 3125

    Generation

    Infected per generation

    Total infected

    1

    1

    1

    2

    5

    6

    3

    25

    31

    4

    125

    156

    5

    625

    781

    6

    3125

    3906

    Based off of our equation, it would take just 6 generations to infect the entire school. This illustrates the dire significance of vaccinations to grant immunity.

    Herd Immunity:
     Herd immunity is a large factor in the infection rates within a population. It dictates that “for each person that is vaccinated the risk of infection for the rest of the community decreases.”[9] In other words, Herd immunity is when the recovered, who are immune, outnumber the healthy susceptible, leading to little chance of creating an epidemic. Vaccination serves as somewhat of a bridge from the susceptible to the recovered, in that the in-patient never goes through the disease. Vaccination is very important to society because it creates herd immunity superficially; the amount of people that are infected or recovered are vastly smaller than a naturally-occurring setup. The Herd Immunity Threshold is the portion of the population that needs to be immune to control transmission of a disease. The Diekmann and Heesterbeek equation for Herd Immunity Threshold is

    Ht = BR–1BR

    = 1- 1BR

    This equation can help us uncover the percentage of people needed to be immune to protect the population. As previously stated, the average range secondary transmissions from one person is 5 (R0 = 5.0) so plugging that into the equation would give us

    1 –  1R0

    = 1 – ( 15

    ) = (45

    )

    Therefore, 80% regarding the population needs to be either immune vaccinated in a totally susceptible environment in order to stop the spread of varicella. [10]

    As more and more people are vaccinated, the herd immunity threshold also
    increases. By decreasing the number of susceptible individuals, the herd immunity threshold decreases.

    Figure C. Visual representation of Herd Immunity taking effect in a population.[11]

     

    Case Trends:

     As vaccinations have become more and more standardized in society and widely implemented, we have experienced a decrease in not only varicella rates but many other diseases as well. Using data from the Morbidity and Mortality Weekly Reports (MMWR), I was able to create a graph.

    Based off of this graph and the data points, I used my calculator to find an equation for the Cases line of best fit.

    y=6.2458E 97 (.89838)x

    The graph was very eye-opening because it really pointed out the drastic downward trend of cases throughout the last few decades. It seemingly will hit zero soon, however that is improbable due to human error; many people do not have access to the varicella vaccine or choose not to partake in it. Since the origins of vaccination, some people have opposed the practice on the grounds that it is not “natural”, or may contain harmful chemicals. In the 1970s, people began to falsely believe that the vaccinations could actually do harm, and blamed cases of autism on the vaccinations. [12] Since 2001, the percentage of people who choose not to vaccinate has quadrupled.

     

    Conclusion:

     I went into this IA with minimal information on the dynamics of epidemiology, and furthermore the importance of vaccination. Every year when I get my shots, I think little of it, but this report highlighted just how much they matter. I regret having the limited scope of just the United State’s data, because I know that in other countries it would vary vastly due to cultural views on anti-vaccination, as well as simply limited access to health care. I felt very privileged and humbled that I live in a place where these options are available to me. If I were to further my research, I would extend my perspective globally, and compare with other countries. Additionally, if there was sufficient data available then I could compare my data with epidemics regarding the past, particularly ones which wiped out populations.

    I have an interest in the healthcare field, particularly in research; as time goes by,  I believe that medicine will advance to further eradicate disease and viruses.

     

     

     

     

     

    Appendix:

    Bibliography

    • “Chickenpox (for Parents).” Edited by Shayan T. Vyas, KidsHealth, The Nemours Foundation, July 2017, kidshealth.org/en/parents/chicken-pox.html.
    • “Chickenpox | Monitoring Vaccine Impact | Varicella | CDC.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, www.cdc.gov/chickenpox/surveillance/monitoring-varicella.html.
    • “Chickenpox (Varicella).” History of Vaccines, www.historyofvaccines.org/index.php/content/articles/chickenpox-varicella.
    • “Chickenpox.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Nov. 2018, www.mayoclinic.org/diseases-conditions/chickenpox/symptoms-causes/syc-20351282.
    • “Chicken Pox (Varicella Zoster Virus) Infection Information.” MyVMC, 31 May 2018, www.myvmc.com/diseases/chicken-pox-varicella-zoster-virus/.
    • “Epidemiology and Prevention of Vaccine-Preventable Diseases.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 11 Aug. 2015, www.cdc.gov/vaccines/pubs/pinkbook/varicella.html.
    • “Facts about Chickenpox.” US National Library of Medicine, Pediatric Children’s Health, Sept. 2005, www.ncbi.nlm.nih.gov/pmc/articles/PMC2722564/.
    • Facts About Chickenpox and Shingles for Adults. National Foundation for Infectious Diseases, Aug. 2009, www.nfid.org/publications/factsheets/varicellaadult.pdf.
    • “History of Anti-Vaccination Movements.” History of Vaccines, www.historyofvaccines.org/content/articles/history-anti-vaccination-movements.
    • Marangi L, Mirinaviciute G, Flem E, Scalia Tomba G, Guzzetta G, Freiesleben de Blasio B, et al.
      (2017) The natural history of varicella zoster virus infection in Norway: Further insights on exogenous boosting and progressive immunity to herpes zoster. PLoS ONE 12(5): e0176845. https://doi.org/10.1371/journal.pone.0176845
    • MATHguide.com. “Geometric Sequences and Series.” MATHguide Is the Source for Interactive Mathematics for Students, Parents and Teachers Called MATHguide, www.mathguide.com/lessons/SequenceGeometric.html.
    • “R Nought and Vaccine Coverage.” Khan Academy, Khan Academy, www.khanacademy.org/science/health-and-medicine/current-issues-in-health-and-medicine/ebola-outbreak/v/r-nought-and-vaccine-coverage.
    • “Reported Cases and Deaths from Vaccine Preventable Diseases, United States, 1950-2013.” Centers for Disease Control and Prevention Epidemiology and Prevention of Vaccine-Preventable Diseases, 13th Edition , Apr. 2015, vaccines.procon.org/sourcefiles/cdc-reported-cases-and-deaths-from-vaccine-preventable-diseases.pdf.
    • “The Mathematics of Diseases.” The Mathematics of Diseases, 25 July 2018, plus.maths.org/content/mathematics-diseases.
    • “Varicella (Chickenpox): Questions and Answers.” Vaccine Information, Immunization Action Coalition, www.immunize.org/catg.d/p4202.pdf.
    • Wharton M. The epidemiology of varicella-zoster virus infectionsExternal. Infect Dis Clin N Amer. 1996;10:571–81.
    • “ What Is Herd Immunity?” PBS, Public Broadcasting Service, www.pbs.org/wgbh/nova/article/herd-immunity/.

    = 125

    a5=(1)55–1

    = 625

    a6=(1)56–1

    = 3125

    Generation

    Infected per generation

    Total infected

    1

    1

    1

    2

    5

    6

    3

    25

    31

    4

    125

    156

    5

    625

    781

    6

    3125

    3906

    Based off of our equation, it would take just 6 generations to infect the entire school. This illustrates the dire significance of vaccinations to grant immunity.

    Herd Immunity:
     Herd immunity is a large factor in the infection rates within a population. It dictates that “for each person that is vaccinated the risk of infection for the rest of the community decreases.”[9] In other words, Herd immunity is when the recovered, who are immune, outnumber the healthy susceptible, leading to little chance of creating an epidemic. Vaccination serves as somewhat of a bridge from the susceptible to the recovered, in that the in-patient never goes through the disease. Vaccination is very important to society because it creates herd immunity superficially; the amount of people that are infected or recovered are vastly smaller than a naturally-occurring setup. The Herd Immunity Threshold is the portion of the population that needs to be immune to control transmission of a disease. The Diekmann and Heesterbeek equation for Herd Immunity Threshold is

    Ht = BR–1BR

    = 1- 1BR

    This equation can help us uncover the percentage of people needed to be immune to protect the population. As previously stated, the average range secondary transmissions from one person is 5 (R0 = 5.0) so plugging that into the equation would give us

    1 –  1R0

    = 1 – ( 15

    ) = (45

    )

    Therefore, 80% regarding the population needs to be either immune vaccinated in a totally susceptible environment in order to stop the spread of varicella. [10]

    As more and more people are vaccinated, the herd immunity threshold also
    increases. By decreasing the number of susceptible individuals, the herd immunity threshold decreases.

    Figure C. Visual representation of Herd Immunity taking effect in a population.[11]

     

    Case Trends:

     As vaccinations have become more and more standardized in society and widely implemented, we have experienced a decrease in not only varicella rates but many other diseases as well. Using data from the Morbidity and Mortality Weekly Reports (MMWR), I was able to create a graph.

    Based off of this graph and the data points, I used my calculator to find an equation for the Cases line of best fit.

    y=6.2458E 97 (.89838)x

    The graph was very eye-opening because it really pointed out the drastic downward trend of cases throughout the last few decades. It seemingly will hit zero soon, however that is improbable due to human error; many people do not have access to the varicella vaccine or choose not to partake in it. Since the origins of vaccination, some people have opposed the practice on the grounds that it is not “natural”, or may contain harmful chemicals. In the 1970s, people began to falsely believe that the vaccinations could actually do harm, and blamed cases of autism on the vaccinations. [12] Since 2001, the percentage of people who choose not to vaccinate has quadrupled.

     

    Conclusion:

     I went into this IA with minimal information on the dynamics of epidemiology, and furthermore the importance of vaccination. Every year when I get my shots, I think little of it, but this report highlighted just how much they matter. I regret having the limited scope of just the United State’s data, because I know that in other countries it would vary vastly due to cultural views on anti-vaccination, as well as simply limited access to health care. I felt very privileged and humbled that I live in a place where these options are available to me. If I were to further my research, I would extend my perspective globally, and compare with other countries. Additionally, if there was sufficient data available then I could compare my data with epidemics regarding the past, particularly ones which wiped out populations.

    I have an interest in the healthcare field, particularly in research; as time goes by,  I believe that medicine will advance to further eradicate disease and viruses.

     

     

     

     

     

    Appendix:

    Bibliography

    • “Chickenpox (for Parents).” Edited by Shayan T. Vyas, KidsHealth, The Nemours Foundation, July 2017, kidshealth.org/en/parents/chicken-pox.html.
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