Vaccines Honor

Science & Health

Requirements

  1. Explain how vaccines work and what the word vaccine means.

    Answer: You must present to the instructor that vaccines are biological preparations that train the immune system to recognize and fight infectious agents (viruses, bacteria) without causing the disease. They contain weakened or inactivated versions, or fragments, of the pathogen; the body produces antibodies and memory cells that will recognize the real agent if it appears in the future. — Vaccination is considered medicine's greatest achievement — it has saved hundreds of millions of lives. The immune system has 'memory' thanks to B and T lymphocytes. Modern vaccines use technologies such as mRNA (Pfizer COVID), viral vector (AstraZeneca), and inactivated ones (Coronavac). Immunity can last months, years, or a lifetime depending on the vaccine and the vaccinated individual.

  2. Tell the story of the emergence of the first vaccine.

    Answer: You should present to the instructor that the first vaccine appeared in 1796, when the English physician Edward Jenner (1749-1823) observed that milkmaids who caught cowpox became immune to human smallpox, a deadly disease at the time. Jenner inoculated pus from cowpox into the boy James Phipps (8 years old) and then exposed the boy to human smallpox — the boy did not get sick. — Before Jenner, smallpox killed 400,000 Europeans per year. His discovery was a milestone of modern medicine. The WHO declared smallpox eradicated in 1980 — the first disease defeated by vaccination. Louis Pasteur, in the 19th century, expanded the concept by creating vaccines for rabies and anthrax. The ethically questionable experiment (on a child) would be prohibited today, but at the time it was revolutionary.

  3. Explain the characteristics, advantages, and disadvantages of the vaccines below:
    • Attenuated;
    • Inactivated;
    • Viral vector;
    • Subunits;
    • RNA.

    Answer: You must present to the instructor: 1) Attenuated (live weakened virus, e.g., MMR, BCG) — advantage: long-lasting immunity; disadvantage: cannot be used in the immunosuppressed; 2) Inactivated (killed virus, e.g., flu, rabies) — advantage: safe for everyone; disadvantage: needs a booster; 3) Viral vector (a harmless virus carries the target's gene, e.g., AstraZeneca COVID) — advantage: strong immunity; disadvantage: immunity against the vector itself may limit booster doses; 4) Subunit (uses only a piece/protein of the virus, e.g., hepatitis B, HPV) — advantage: very safe, without the whole virus; disadvantage: usually needs a booster and an adjuvant; 5) RNA (the mRNA teaches the cell to produce the virus's protein, e.g., Pfizer and Moderna) — advantage: fast production and high efficacy; disadvantage: requires storage at very low temperature. — Each type has its application. MMR (attenuated) is highly effective and given from 12 months on. Flu (inactivated) needs annual updating. mRNA was a recent technological disruption — a pre-existing technology, popularized during the pandemic. Subunit (HPV) vaccines are ultra-safe. Viral vector (AstraZeneca) is versatile but has limitations. Knowing each type helps to understand the complete vaccination schedule.

  4. What was the first disease eradicated in the world as a result of vaccination?

    Answer: You should present to the instructor that the first disease in the world to be eradicated by vaccination was smallpox, officially declared eradicated by the World Health Organization (WHO) on May 8, 1980, after a global vaccination campaign started in the 1960s. — Smallpox killed about 300 million people in the 20th century before being eradicated. The last natural case was in Somalia, in 1977. The vaccine came from Jenner's original work in 1796, refined over the centuries. Poliomyelitis is in the final stage of eradication, with few cases in Afghanistan and Pakistan recently. The WHO coordinated the victorious global campaign.

  5. Make a table of the vaccines provided by the public health service of your country. What diseases do they prevent, and when should they be administered?

    Answer: Table of the main vaccines offered by the SUS (National Vaccination Schedule) — disease it prevents and when to administer: 1) BCG (severe forms of tuberculosis) — single dose at birth; 2) Hepatitis B — at birth (first 24h); 3) Pentavalent (diphtheria, tetanus, whooping cough, Haemophilus influenzae b, and hepatitis B) — 2, 4, and 6 months; 4) IPV/OPV Poliomyelitis (infantile paralysis) — 2, 4, and 6 months + boosters at 15 months and 4 years; 5) 10-valent Pneumococcal (pneumonia, meningitis, otitis) — 2 and 4 months + booster at 12 months; 6) Human Rotavirus (severe diarrhea) — 2 and 4 months; 7) Meningococcal C (meningitis) — 3 and 5 months + booster at 12 months; 8) Yellow fever — 9 months + booster at 4 years; 9) MMR (measles, mumps, rubella) — 12 months + MMRV (with varicella) at 15 months; 10) Hepatitis A — 15 months; 11) DTP (diphtheria, tetanus, whooping cough) — boosters at 15 months and 4 years; 12) HPV (cervical cancer and others) — 9 to 14 years; 13) Meningococcal ACWY — adolescents 11-14 years; 14) dT/dTpa (diphtheria and tetanus; pregnant women) — booster every 10 years; 15) Influenza (flu) — annual for priority groups; 16) COVID-19 — according to campaigns. Build the table with columns Vaccine | Disease it prevents | Age/when to administer. — The SUS offers the world's most comprehensive national program for childhood vaccination. The schedule begins at birth with BCG and hepatitis B. MMR is a single dose at 12 months + booster at 15. HPV is free for girls aged 9-14 and boys aged 11-14 (protection against cervical cancer). Adults have their own schedule including flu and dT (diphtheria/tetanus).

  6. Explain the stages for the development of a new vaccine.

    Answer: You must present the stages to the instructor: 1) Basic/pre-clinical research — study of the agent, identification of antigens, tests in the laboratory and in animals; 2) Phase 1 (safety) — tests in small groups of healthy adults (20-100 people); 3) Phase 2 (dose and immunogenicity) — hundreds of volunteers, finding the ideal dose. 4) Phase 3 (efficacy) — thousands of volunteers comparing those who received the vaccine with those who received a placebo, confirming efficacy and safety; 5) Approval and registration — the regulatory agency (ANVISA in Brazil) reviews all the data and authorizes use; 6) Large-scale production and Phase 4 (post-marketing) — pharmacovigilance: monitors rare effects and long-term efficacy now that the population is using the vaccine. — Developing a vaccine normally takes 10-15 years. COVID-19 was an exception (1 year) due to global mobilization and pre-existing mRNA technology. Each phase eliminates failing candidates — only ~10% reach Phase 3. ANVISA uses rigorous criteria like the FDA. Phase 4 detects rare reactions (1 in millions) that only appear with large-scale use. Without this rigor, the risks are immense.

  7. What is the importance of having a large number of vaccinated people? What is herd immunity or collective immunity?

    Answer: 1) Importance of many people being vaccinated: it creates a collective barrier against contagious diseases, protecting even those who cannot be vaccinated (newborns, immunosuppressed people, allergic people), because it reduces the circulation of the infectious agent in the population. 2) What herd (or collective) immunity is: it is the phenomenon in which, when a large part of the population (about 70-95%, depending on the disease) is immune (through vaccination or by having already had the disease), the infectious agent can no longer circulate — there are too few susceptible people to infect, which interrupts the chain of transmission and indirectly protects those who are not immune. — R0 (basic reproduction number) defines the threshold — measles R0=12-18 (requires 95% immune), COVID R0=2-3 (requires 60-70%). Anti-vaccinationism threatens collective immunity — measles outbreaks resurged in 2018-2024 in places with vaccine coverage below the threshold. Getting vaccinated is an act of citizenship that protects the community, especially the most vulnerable who cannot protect themselves directly on their own.