What are vaccines?
Vaccines save millions of lives every year. Chances are good you’ve gotten a vaccination sometime in your life. Maybe it was the Measles, Mumps and Rubella vaccine back when you were a child. Or maybe it was the flu shot during last year’s flu season.
But do you really know how vaccines work?
Medically, the term vaccine describes a suspension of killed or weakened microbial cells or any other infectious substance, such as toxoids or venoms. This suspension is delivered into an individual’s body to produce boost their immune system.
This works by training a body’s immune system to produce unique antibodies designed to respond to specific chemical signatures, known as antigens, present in viruses, bacteria, and other pathogens.
The process of administering the vaccine to immunize a person is called either vaccination or immunization.
British physician Edward Jenner invented the first vaccination in 1798. He administered cowpox, a disease common among farmworkers and milkmaids, to patients to immunize them against smallpox, a more deadly virus. When a patient became sick with cowpox, their immune system would learn to produce antibodies that affect both cowpox and the closely related smallpox.
Categories of Vaccines
We classify vaccines into six categories:
- Replicative vaccines
- Non-replicative vaccines
- Cellular component vaccines
- Synthetic peptide vaccines
- Anti-idiotype vaccines
Certain bacteria produce a substance known as exotoxins, which are both toxic and antigenic (encouraging the production antibodies.) When these exotoxins are treated with formaldehyde or heat, they lose their toxicity but retain their antigenic properties. When treated this way, the substance becomes a type of vaccine we call a toxoid. A toxoid is used as a vaccine to induce active immunity based on the formation of specific antibodies, usually as an antitoxin.
There are numerous bacterial vaccines that provide immunity or resistance to some of the most common bacterial infections and diseases. Some of these include:
- Cholera: Usually involving some portion of the V. cholerae bacteria, this vaccination is most commonly delivered orally. However, there are injectable versions available as well. The resistance provided by these vaccines typically last only a few years. If you are travelling to cholera-prone regions of the world, you should check with your pharmacist to see if you should receive a cholera vaccine.
- Diphtheria: This vaccine, made from purified diphtheria toxoids, is usually administered to infants via an injection. Generally, diphtheria vaccinations are found combined with tetanus vaccinations.
- Meningococcal (meningitis and meningococcal septicemia): Another injected vaccine, this one is made of purified polysaccharide from N. meningitis bacteria. In Canada, treatment is usually delivered twice, once as an infant, and once as an adolescent. However, in parts of the world where meningococcus is more common, such as Sub-Saharan Africa, it is recommended that adults continue to receive boosters every 3 to 5 years.
- Pertussis (whooping cough): Made of up either whole or partial B. pertussis bacteria, this vaccine is usually administered to infants, typically in combination with diphtheria and tetanus vaccines as a DPT vaccine, with boosters offered to children as well.
- Pneumococcal pneumonia: This vaccine uses purified polysaccharide from the Strep. Pneumonie bacteria, and provides resistance to strains of bacteria that cause pneumonia, meningitis and bacteremia. In most cases, this vaccine is administered to both infants under 2 and seniors over 65. However, adults between 19 and 65 who smoke may wish to consult with their doctor or pharmacist about receiving a booster shot.
- Tetanus: This vaccine uses a purified tetanus toxoid, and is delivered to infants alongside the Pertussis and Diptheria vaccines as part of the commonly administered DPT vaccine.
- Tuberculosis: The commonly used BCG vaccine is administered to children in countries where tuberculosis is still a major threat. While this vaccine can provide resistance in infants and children, it is less effective in adults. As such, it is not usually prescribed to mature patients.
- Typhoid fever and paratyphoid fever: There are numerous types of typhoid and paratyphoid vaccines, most involving dead S. typhi, S.schottmulleri, and S.paratyphi A bacteria. This vaccine is not usually prescribed in Canada, though travellers to regions where typhoid fever is still prevalent, such as Southeast Asia, should consult with their pharmacists about vaccination.
As with bacteria, there are numerous viral vaccines. There are two principal types of viruses used in vaccines. One is inactivated, or killed, vaccines, which use pathogens that are dead. Attenuated vaccines use live viruses that have been weakened, and thus are largely harmless to humans. Some of the more common viral vaccines include:
- Influenza: The influenza vaccine, also known as flu shots, change every year to adapt to mutations in the influenza virus. This means the effectiveness of a flu shot can vary from year to year. Still, it is recommended children and adults get a flu shot every year, and the government of Alberta provides flu shots to all Albertans free of charge.
- Measles: Available both on its own, and as part of the MMR vaccine with mumps and rubella. It is usually given to toddlers.
- Mumps: Like the measles vaccine, the mumps vaccine is usually given to toddlers as part of the MMR vaccine.
- Poliomyelitis (polio): Can be found in two common forms, either the orally-delivered attenuated (Sabin) vaccine or the inactivated (Salk) injected vaccine. These vaccines are commonly provided to infants and children. However, adults who are at risk of exposure to the virus should consult with their pharmacists about receiving a booster.
- Rabies: Both doctors and veterinarians use this, as rabies vaccines are effective in both humans and dogs. It is usually preferred to vaccinate pets against rabies, so most humans won’t receive this treatment. However, those at high risk of rabies, such as those who work with pets and wildlife, may also be immunized.
For a routine immunization schedule designed for Albertans, check out the Alberta Health Services’ guide at immunizealberta.ca.
Role of Pharmacy Assistants in Vaccination
Due to the increased number of people travelling, pharmacy assistants will need to provide focused care to a rapidly growing base of patients in need of specialized vaccines, such as for cholera, hepatitis, or typhoid fever. Pharmacy assistants retrieve and review patient immunization histories for pharmacists, so they should be knowledgable of how vaccines work and what vaccines a patient might need.
Role of Medical Office Assistants in Vaccination
Patients seeking vaccinations from doctors are among the most frequent visitors to a medical office, be they new parents or travellers preparing for a vacation. Medical office assistants, like pharmacy assistants, should be comfortable with retrieving and reviewing a patient’s immunization histories for doctors and nurses.