By Victor Romulo Gallardo Dumaguing, MD
A SIXTY-FOUR dollar question, just like Shakespeare’s “to be or not to be”
There’s a national dilemma; parents, especially mothers vacillate. Pediatricians as a rule initiate, encourage and suggest, parents hesitate. Understandably, with the public outcry about the Dengvaxia still fresh in the minds of Filipinos, parents are torn between a yes and a no decision as to whether they will bring their children for immunization, and that might explain too, the phenomenon of vaccine hesitancy among adults, especially senior citizens who are, sad to say, susceptible to COVID-19 infection and most likely to succumb to its more serious, and fatal complications.
The sad reality is that microbes are ubiquitous- they are everywhere- and every human being is exposed to any of them at the moment of birth, be it at home or in the supposed aseptic environment of the delivery room of the most modern hospital. Fossil studies reveal that microbes antedate homo sapiens on the surface of the earth. Thus, humans must learn to contain them and prevent them from causing disease in the form of infections.
Standard textbooks in microbiology and immunology define vaccines as a material that can artificially induce immunity to an infectious disease, usually after ingestion of the material (oral polio vaccine) or through injections. In other words, vaccines deliberately, that is purposely exposes a person to an attenuated or weakened version of the pathogenic microbe like virus, bacteria to challenge and stimulate the person’s own immune system to produce protective antibodies and the so-called memory cells, whose function is to mount another aggressive defensive force should the person be exposed to the same microbe in the near future.
Thus, booster doses of some vaccines are needed to make sure that the defense is always primed and ready for subsequent similar infectious processes. The immunity provided by vaccination or immunization is called artificial active immunity; in contrast to the antibodies a person forms after actually getting sick, vaccination simulates or copies an infectious process – not a full blown clinical disease – with the purpose of provoking an antibody response. This explains why, vaccinated persons, adult or child usually have a low grade fever a few hours after immunization which your family doctor would readily explain that now, your body is reacting, starting to produce antibodies.
Various materials are used in vaccines. Most vaccines are made from living or dead (inactivated) pathogens or even from actual toxins which the microbes themselves produce. In general, vaccines made from living organisms are most effective but they must be prepared from harmless organisms that are anti genetically closely related to the microbe or from what is called attenuated-weakened microbe that have been genetically changed so that they are no longer capable of producing all the signs and symptoms of the actual disease..
Progress in research propelled by a broad background in biochemistry and pharmacology showed that it was practical and found it safe to vaccinate against several diseases by combining specific vaccines in a single injection. Classic examples are the DPT vaccine which contains toxoids to prevent diphtheria and tetanus and the antigenic portion of killed bacteria (Bordatella pertussis) to prevent whooping cough. Mothers all over the world are thankful there is the reliable MMR vaccine for measles, mumps and rubella (German measles)
Basic requirements for a vaccine to be called “ideal” include: it must contain enough antigenic determinants to stimulate and challenge the immune system of the person to produce the desired amount of effective antibodies; it must contain antigenic determinants from all strains of the microbe that cause the disease- in polio, by strains of Leon, Brunhilde, Lansing- in which case, these vaccines are called polyvalent. Thus, a monovalent vaccine is specific only for one strain of the microbe.
The word vaccine come from “vacca”, the Latin word for cow. The medical world remembers Edward Jenner, the British physician who volunteered to be immunized by the then so-called Chinese method using powder prepared from dried smallpox scabs – by inhaling the powder. He later noticed that milkmaids working closely with cows never had smallpox thus he hypothesized that having the milder form of cowpox (vaccinia minor) protected the patients from having the more serious, deforming and fatal smallpox, Using materials from dried cowpox lesions, Jenner vaccine was born and the whole world is eternally grateful.