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May 07, 2021

OWSD Nigeria National Chapter University of Port Harcourt Branch series of scientific communications: Nnenna Frank-Peterside on VACCINE HESITANCE: MAKE INFORMED DECISIONS




 Long before the practice of immunization as we know it today people had made some interesting observations which led them to some practices. Those observations were that people who recovered from an infectious disease did not suffer from it again and if they did, it was very mild. The word “immunitas” a latin word that conveys the idea of “exemption from duty has since been used to convey this idea. About AD 649, a Chinese Doctor posited that the most effective method of preventing a reoccurrence of rabies is by covering people with the sick dog brain (1). As early as AD1000 the Chinese had an ancient custom where the content of smallpox pustule was dried and given to children to inhale. This protected them or ameliorated the effect of smallpox in these children (2). These and many more show that for over a millennium, Chinese doctors have tried to cure or prevent disease by some kind of immunization.

Immunization as we know it today was preceded by variolation, smearing of a skin tear with cowpox to confer immunity to smallpox. A British physician, Edward Jenner (1749-1823) observed that milk maids had mild or no smallpox that was killing a whole lot of people. He proceeded to perform his own experiment when on the 14th of May, 1796 he lacerated the skin of a 13 year old boy and inserted pustule material from the milder cowpox. On the 1st of June, 1796, he challenged that boy with smallpox material. The boy only suffered from mild cowpox. He repeated this experiment with 23 people and concluded that those who had cowpox were immune to smallpox. He called the procedure vaccination which denoted “from cow” to differentiate it from inoculation. By 1840, vaccination became free for all. In 1853, it was made compulsory in Britain and Europe followed, immediately. Over the 18th and 19th centuries systemic mass smallpox vaccination and surveillance led to the global eradication of same in 1979 as announced by world health assembly (3).

A vaccine, is defined as a product (weakened, killed or fragmented microorganisms or toxins) that stimulates a person’s immune system to produce immunity (antibodies or specialized T lymphocytes) to a specific disease, protecting the person from that particular disease. Vaccination is therefore an act of introducing a vaccine into the body to produce immunity to a specific disease. Immunization is the process by which a person becomes protected against a disease through vaccination. These two words are usually interchanged. The issue of vaccine resistance is almost as old as the vaccines themselves. Vaccine resistance is therefore nothing new. On the other hand health and medical scholars describe vaccination as one of the top ten achievements of public health in the 20th century. The anti-vaccination movement started in England where Jenner reported the vaccination procedure.  The reasons for their opposition were listed as sanitary (cutting and bleeding were unhygienic); religious (scaring of human flesh and inserting substance  form a lower being, cow, was unsustain); scientific (were not convinced about the transmission of these disease causing organisms from person to person) and political (infringement of human right).This issue spread to the United States of America and later resulted in the  vaccine act of 1898 removing the penalty for those who opted out and adding the “conscientious objector clause” giving them  an exemption certificate. Many vaccines have since been introduced with the following questions constantly asked;- is a particular vaccine necessary,- is the vaccine safe- can we trust expert advice and-are the information on side effects adequate and correct. These issues have continued into the 9th and 20th centuries. The request now, is, “Green out vaccines”, remove the toxins (4). To understand how vaccines work it is necessary to understand how the immune system works. When pathogens overcome the first and second lines of defense, they encounter the third which recognizes them as foreign and mounts an attack on them using a wide array of white Blood Cells which work together to eliminate same.(5). The first exposure produces antibodies, specialized T cells and memory cells to that organism. Upon re-exposure to the same organism, the memory cells are able to clear the organism before they can establish and cause disease. Vaccines work in the same manner but they contain weak or killed organisms, so they do not cause full blown disease, and in addition produce memory cells. If our body encounters same organism in the future, our bodies remember and mount an immediate clearance before the pathogen can settle to cause disease. There are different types of vaccines each with their advantages and disadvantages. They include the following; weakened (live attenuated), inactivated (killed), subunit, conjugate, recombinant, polysaccharide, toxoid, mRNA, viral vector, DNA and recombinant vector vaccines.

Benefits of immunization can be grouped in two, individual and population levels. For the individual, vaccine preventable diseases are reduced and recipients are kept in good health (6). Herd immunity is described as resistance to the spread of an infectious disease within a population that is based on pre-existing immunity of a high proportion of individuals as a result of previous infection or vaccination. The level of vaccination needed to achieve this varies for diseases. Vaccine failure can be primary or secondary. Primary vaccine failure is defined as the inability of a recipient to mount a protective response after a dose of vaccine. Secondary vaccine failure describes a gradual loss of immunity over years i.e. waning immunity. Another concept of interest is, virus variant. This is an isolate whose genome sequence is different from that of a reference virus. Virus variants are a significant public health concern. It is untrue that vaccines don’t protect against virus variants. People are therefore advised not to worry about new variants if they were fully vaccinated. The risk therefore is primarily for the unvaccinated. Vaccine hesitance is defined as the delay in acceptance or refusal of vaccines despite availability of vaccine services. It is complex, varying in time and place as well as with vaccines (7). It has been suggested that vaccine hesitance might be as a result of system failure, limited availability of vaccination service and curtailment of vaccine services in the presence of conflict or natural disaster among others. It is important to determine the reason for hesitance to be able to address the issue (8). Vaccine hesitance is influenced by the “3 Cs”; confidence, complacency and convenience.

I discovered that many mothers have vaccinated their children without having an understanding of what a vaccine is and how it works. I also discovered that many people were saying they will not accept the covid-19 vaccine. When asked why, they initially had no reason. Then on second thought said they were concerned about the side effects. The aim of this lecture was to give information, encouraging people to do their research properly, ask reliable people the right questions and from a place of knowledge make informed decisions on vaccine related issues. I hope I have achieved that aim.


1. Langer, W. (1976).Immunization against Smallpox before Jenner. Scientific American, 234(1)112-117

2. Xuetao Cao (2008). Immunology in China: the past, present and the future. Nature Immunology 9: 339-342.

3. World Health Organization. Smallpox, Retrieved on May, 5, 2021 from:

4. The history of vaccines. History of anti-vaccination movements. Retrieved May 3, 2021, from

5.The Immune System: Information about Lymphocytes, Dendritic Cells, Macrophages, and White Blood Cells. Retrieved, May,1,2021; from

6. Foundation for infectious diseases. 10 reasons to get vaccinated. Retrieved May, 5, 2021 from: https:///

7. Robb Butler (2015). Vaccine Hesitancy: what it means and what we need to know in order to tackle it. Journal of Vaccine. From: https;//

8. MacDonald, N.E,(2015). SAGE Working Group on Vaccine Hesitancy. Vaccine hesitancy: Definition, Scope and determinants. Vaccine 33934); 4161-4



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