1 / 12

To Vaccinate or Not to Vaccinate?

To Vaccinate or Not to Vaccinate?. That is the question. Joanne Mann J.L.Mann@Massey.ac.nz. Cholera Dengue Diphtheria E coli Influenza Haemophillus influenzae B Hepatitis A Hepatitis B Human Papillomavirus Japanese encephalitis Measles Meningococcus Mumps

anka
Download Presentation

To Vaccinate or Not to Vaccinate?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. To Vaccinate or Not to Vaccinate? That is the question Joanne Mann J.L.Mann@Massey.ac.nz

  2. Cholera Dengue Diphtheria E coli Influenza Haemophillus influenzae B Hepatitis A Hepatitis B Human Papillomavirus Japanese encephalitis Measles Meningococcus Mumps Tetanus/Neonatal tetanus Pertussis (whooping cough) Pneumococcus Poliomyelitis Rabies Rotavirus Rubella Shigella Smallpox Tuberculosis Typhoid Yellow fever Varicella (chickenpox) Vitamin A Other diseases Vaccine-Preventable Diseases* *Source: http://www.who.int/vaccines/en/vaccprevdis.shtml To Vaccinate or Not to Vaccinate?

  3. Why Be Vaccinated? • So that you don’t get infected. • So that you don’t pass the infection on. • But… • What about the negative side effects from a vaccination? To Vaccinate or Not to Vaccinate?

  4. Should I be Vaccinated? • It depends on the relative costs of remaining susceptible and of being vaccinated. • But, if everyone around you is vaccinated… To Vaccinate or Not to Vaccinate?

  5. On To the Maths… • Let p be the proportion of the population that are vaccinated (then 1-p aren’t vaccinated). • Let Cvbe the cost of being vaccinated, and Cs be the cost of remaining susceptible. • Let S∞be the proportion of the population that are still susceptible after an epidemic. To Vaccinate or Not to Vaccinate?

  6. On To the Maths… • S∞ is calculated from • R0is the basic reproduction ratio: the number of secondary cases that would occur from a primary case in a fully susceptible population. To Vaccinate or Not to Vaccinate?

  7. Two Choices • Be vaccinated, then your expected individual cost is Cv. • Remain susceptible, then your expected individual cost is 1-p-S∞ is the proportion of the population who were infected during the epidemic. To Vaccinate or Not to Vaccinate?

  8. The Community • The cost to the community will be a combination of the two individual strategies: • What is the best option? To Vaccinate or Not to Vaccinate?

  9. To Vaccinate or Not to Vaccinate?

  10. The Best Individual Strategy • The best strategy for the individual varies depending on Cv and Cs. • If Cv < Cs then the expected cost of vaccination is lower than the cost of remaining susceptible, unless a significant proportion of the population is vaccinated. • Best Strategy: To Vaccinate or Not to Vaccinate?

  11. Best for the Community • The lowest expected cost, for the community, is to always vaccinate the proportion of the population equal to • So, convince every one you come in contact with to be vaccinated – then you don’t have to be! To Vaccinate or Not to Vaccinate?

  12. References • Bauch, C. T., Galvani, A. P. and Earn, D. J. Group Interest Versus Self-Interest in Smallpox Vaccination Policy.Proc Natl Acad Sci U S A. 2003 Sep 2;100(18):10564-7 (available online: http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=12920181) • Mann, J. Modelling repeated epidemics with general infection kernels. To Vaccinate or Not to Vaccinate?

More Related