Vaccines Across Lifespan Part 1 PDF

Vaccines Across Lifespan Part 1 COM 116 Racha Khaled, MD. MRCOG, CABOG, MOG  Objectives Introduce immunity and vaccinations as medical terms. Develop a knowledge about the types of immunity and its relation to vaccination. Identify the different...

Vaccines Across Lifespan Part 1 COM 116 Racha Khaled, MD. MRCOG, CABOG, MOG  Objectives Introduce immunity and vaccinations as medical terms. Develop a knowledge about the types of immunity and its relation to vaccination. Identify the different types of vaccinations, pros and limitations of each one of them. Study the financial impact of vaccinations on the world economy. Extended explanations about different vaccines will be presented in Part 2 of this lecture next week. How are vaccines and public health related? The History of Vaccines https:// youtu.be/E_PKQ_M7AtU  How are Vaccines and Primary Health Care Related? Vaccination is a key component of preventive health services offered in primary health care settings. Primary health care provides a platform for equitable access to vaccinations. Primary health care providers educate patients about the importance of vaccines. Disease Surveillance*  Vaccines and Year 2020 In 2020 The World Health Organization and UNICEF warned of an alarming decline in the number of children receiving life-saving vaccines around the world. This is due to disruptions in the delivery and uptake of immunization services caused by the COVID-19 pandemic. According to new data by WHO and UNICEF July 2020.  #Vaccines Work for All The aim of World Immunization Week is to promote the use of vaccines to protect people of all ages against disease. The week takes place from 24-30 April. Nearly 20 million children are still unvaccinated and under- vaccinated worldwide. Immunity is the ability of the body to resist harmful disease organisms that can cause infectious diseases. Immunology is study of the structure and function of the immune system.  Types of Immunity 1- Natural immunity: is a consequence of stimulation of immunity by exposure to an infection. 2.-Herd immunity: This develops when a high proportion of the target population in the community has been immunized with vaccines, usually 80% and more, in order to prevent the spread of infectious diseases. 3. Passive immunity( ready-made antibodies): Immunity that results from transfer of antibodies from one person or animal to another person and this offers antibodies that can protect a person temporarily. Examples?* When to use passive immunity?** 4. Artificial immunity (vaccination) or active immunity: when a person’s own immune system develops protection after a vaccination. It usually lasts for many years.  Herd immunity It arises when a high percentage of the population is protected against a virus or bacteria, making it difficult for a disease to spread because there are so few susceptible people left to infect. Herd immunity prevents severe outbreaks of diseases. Herd Immunity is particularly crucial for protecting people who cannot be vaccinated. Who are the people that we cannot give them vaccines?* Herd Immunity  How herd immunity is achieved? Through vaccines and infection Reaching herd immunity through vaccination has drawbacks: o Protection from some vaccines can wane over time, requiring revaccination. o People may not get all the shots needed to be completely protected from a disease. Herd immunity can also be reached when a sufficient number of people in the population have recovered from a disease and have developed antibodies against future infection. Drawback: - o Need a large number of population to be infected >90% in most cases o The infection might be severe and may cause disability or death  Vaccination Vaccines safely and effectively use a small amount of a weakened or killed virus or bacteria or bits of lab-made protein that imitate the virus in order to prevent infection by that same virus or bacteria. A vaccine will usually prevent the onset of a disease or else reduce its severity. The goal of public health is to prevent disease. It's much easier and more cost-effective to prevent a disease than to treat it.  Types of Vaccines Live-attenuated vaccines - includes heterogeneous vaccines Inactivated vaccines Subunits vaccines Toxoid vaccines COVID-19 Vaccine Types mRNA Vaccine (Pfizer-BioNTech and the Moderna) Viral Vector Vaccine (AstraZeneca)  Live attenuated vaccines  These vaccines are so similar to the natural infection. They consist of live pathogens that have been weakened by heat or chemical treatment, to a non-pathogenic form. Pros: 1-They help prevent, and create a strong and long-lasting immune response. 2- They produce memory cells and that’s why 1 or 2 doses only of most live vaccines can give a lifetime of protection against a bacteria or virus that causes the disease. Cons: 1-People with weakened immune systems, long-term health problems, or people who’ve had an organ transplant, should not receive these vaccines. 2-Need to be kept cool, so they don’t travel well. 3- Very rarely, the vaccine by itself induces the disease in some people. 4- If the vaccine is grown in a contaminated tissue culture it can be contaminated by other viruses (e.g. retro viruses with measles vaccine).  Heterogeneous Vaccines Heterogonous vaccines are a subgroup of live attenuated vaccines produced from different strains or types of a pathogen. BCG, or Bacille Calmette-Guerin, is a heterogonous vaccine that protects against tuberculosis.  Inactive vaccines  They consist of a whole virus or bacteria that has been killed by heat, radiation, or chemicals. Pros 1-They are easy to produce and store 2-Do not induce the disease at the time of the vaccination 3-People with weakened immune systems, long-term health problems, or people who’ve had an organ transplant, can receive these vaccines. Cons Cause a weaker immune response so people require multiple doses or booster shots to get full immunity.  Toxoids  Toxoid is an inactivated toxin: a toxin of a pathogenic organism, basically bacteria, treated so as to destroy its toxicity but leave it capable of inducing the formation of antibodies. Pros: Toxoid vaccines are extremely effective against bacteria whose harmful effects are caused by toxins. Cons: 1- you may need booster shots to get ongoing protection against diseases. 2-They create immunity to the toxin of the bacteria that cause a disease but not to the bacteria itself.  Subunits Vaccines  Subunit vaccines, like inactivated whole-cell vaccines, do not contain live components of the pathogen. They differ from inactivated whole-cell vaccines, by containing only the antigenic parts of the pathogen. These parts are necessary to elicit a protective immune response. Pros: 1- Have no live components so it will not induce the disease. 2-safer and more stable than live attenuated vaccines. Cons: 1-costly, as antigenic properties of the various potential subunits of a pathogen must be examined in detail to determine which particular combinations will produce an effective immune response within the correct pathway. 2- Often a response can be elicited, but there is no guarantee that immunological memory will be formed for future responses.  Components of a Vaccine -Antigens are the components derived from the structure of disease-causing organisms, which are recognized as ‘foreign’ by the immune system and trigger a protective immune response to the vaccine. -Stabilizers are used to help the vaccine maintain its effectiveness during storage. -Adjuvants are added to vaccines to stimulate the production of antibodies against the vaccine to make it more effective. -Antibiotics (in trace amounts) are used during the manufacturing phase to prevent bacterial contamination of the tissue culture cells in which the viruses are grown. Benefits in Economic Evaluation of Vaccinations  Question A mother of 6 year old boy came to a primary care clinic to ask the physician a question: My child is invited to a chickenpox party, do you think that I should let him go though he is not vaccinated against chickenpox? would it be better for my child to get the chickenpox this way?  Resources World Health Organization www.who.int Centers for Disease Control and Prevention www.cdc.gov Hp2020: www.healthypeople.gov First Aid USMLE Step1by Tao Le, Vikas Bhushan