Dutch scientist Antonie van Leeuwenhoek first saw bacteria through a microscope in 1676. 255 years later, viruses were first seen with the introduction of the electron microscope in 1931. The reason it took another quarter of a millennium to see viruses after bacteria is because of the size difference between them. Furthermore, visual identification was hampered by the limits of technology.
The first antibiotic was developed in 1910 to treat syphilis, and in 1944, during WWII, mass production of penicillin began. It wasn’t until a generation later, however, that antiviral therapy came into clinical use.
Again, size mattered. Bacteria are generally larger and have more parts to attack: cell membranes, organelles, etc. Viruses, although simpler, prove more difficult to attack, as they require attacks at the genetic level.
The first antivirals: vaccines
Vaccines were developed before the actual discovery of the virus. Doctors knew there was something making people sick, something that could be transferred to other people that not only making them sick but also to make them immune. Such was the germ theory of the 19th century. Before this insight, the accepted theory was that illness was caused by “bad air.” In 1796, Edward Jenner used cowpox, a virus similar to smallpox, and injected it into people to prevent the deadly human version of the infection. About a hundred years later, Louis Pasteur tinkered with altered viruses to use as vaccinations. Vaccines for rabies, yellow fever, and polio followed.
Trickery and deception
Vaccines work via the following:
- Live, attenuated virus;
- Inactivated virus;
- Toxoid exposure;
- Synthetic mimicking of viruses.
Vaccines trick the body’s immune system into thinking it is infected, creating an immunological memory (planned strategy) for when an actual infection occurs. A vaccine is merely a practice drill that keeps the immune system prepared for the real thing. The deception is that the immune system does not know it’s a drill, and the trick is to introduce the body to a milder version of the disease being prevented.
Kinder, gentler viruses are created by attenuating the virus, which means altering it so that it is less virulent or possibly even harmless but keeping it alive, so to speak, to stimulate the immune system into action. Measles, mumps, and chickenpox vaccines do this.
Inactivated viruses use parts of the virus only. It’s enough for one’s immune system to see the infection or anything similar coming so that an infection is nipped in the bud. The flu vaccines are inactivated viruses.
Toxoid vaccines use a by-product of the virus, which will immunize the body against the damage done by the by-product and not against the infection itself. This approach is usually used with bacteria, such as tetanus and diphtheria.
What are the recommended vaccines?
Vaccination, or the act of receiving a vaccine, has been a cornerstone of public health since the 20th century. It is recommended that all children begin a series of vaccinations as early as the newborn period. The schedule of immunizations varies from country to country, but this information can be easily obtained from the World Health Organization’s website.
Generally, these schedules include the following:
- The hepatitis B vaccine is an inactivated virus vaccine and is given intramuscularly within 24 hours of birth, again at one month of age, and again somewhere between 6–12 months of age.
- The rotavirus vaccine is live and attenuated and given orally at two, four, and six months of age.
- Diphtheria, tetanus, and pertussis (DPT) vaccines: Diphtheria and tetanus vaccines are toxoid vaccines, while the pertussis is an inactivated virus. These vaccines are given intramuscularly at two months, 15–18 months, and 4–6 years of age. Afterwards, the tetanus vaccine is given about every five years.
- The H. influenza type B conjugate vaccine is inactivated and given intramuscularly at two, four, six months, and then between 12 and 15 months of age.
- The polio vaccine is an inactivated vaccine and is given intramuscularly or subcutaneously at two months of age, four months of age, somewhere between six to 18 months of age, and then when a child is between four and six years old. The oral version has not been used in North America since 2000 but is still used in many parts of the world as part of the polio eradication project.
- The influenza vaccine is an inactivated virus vaccine and is given intramuscularly at six months of age and annually thereafter. The nasal vaccine is a live, attenuated virus and is not generally recommended for the current influenza season.
- The MMR (measles, mumps, rubella) vaccine is a live and attenuated virus vaccine and is given subcutaneously at 12–15 months of age and again at four to six years of age.
- The rubella vaccine is given intramuscularly and should be given to women who are not immune, especially during pregnancy, and to all non-immune healthcare workers.
- The varicella (also known as varicella-zoster, VZV, or chickenpox) vaccine is a live and attenuated virus vaccine that is given subcutaneously at 12–15 months of age and again between the ages of four and six.
- The hepatitis A vaccine is an inactivated virus vaccine and is given by intramuscularly between 12 and 24 months of age and then repeated six months after the injection.
- Meningococcal vaccines are inactivated virus vaccines and are given intramuscularly at ages 11–12 and at age 16.
- There are three versions of the human papillomavirus (HPV) vaccine; each covers different types of the virus, although all contain protection from types 16 and 18, the ones implicated most frequently in cervical and throat cancer. Boys and girls should get three doses of the same formulation beginning from when they are 11–12. These doses should be separated by at least six months each. The doses are given via intramuscular injection.
Schools typically require recorded documentation of the scheduled vaccinations. However, there are problems that will delay or prevent vaccinations, including the following:
- Inconvenience, which is a problem of parental compliance
- Lack of confidence that vaccines work
- Distrust: There are fears of vaccines causing autism, autoimmune disease, etc. that are intensified by negative and sensational tabloid journalism and other media misinformation.
- Medical exemptions, such as a history of anaphylaxis or being immunocompromised
- Religious exemptions—beliefs that oppose immunization.
- Philosophical exemptions—parents who have moral and/or philosophical beliefs against vaccines.
- Parental belief that a child is not at risk because such diseases are rare—Such beliefs are rare because so many people are immunized; no child should be purposely excluded.
Parental hesitancy is a pediatric concern, and education is the best way to assuage it. Nevertheless, mandatory vaccination laws, designed to establish “herd immunity,” protect the unvaccinated as well. There are countless studies with overwhelming evidence-based results that have proven the efficacy of immunizations. Vaccines have made our 21st century lives the healthiest in the history of the world.
It took a long time to find the virus and a longer time to understand it enough to meet it head on. We have only been partially successful in eradicating some of these viruses from the Earth. Small pox is said to be eradicated, barring any militarized depots. The USA in 1979 and Canada in 1994 were declared polio-free. As time and the science of virology go forward, there is hope for additional progress. Thanks to vaccines for rubella (German measles), rabies, mumps, chickenpox, measles, HPV, and meningitis, most people in the industrialized world can look forward to a virus-resistant life. The number of cases of vaccine-preventable illnesses has declined by more than 90% since routine childhood immunizations were introduced.