Adult Immunization in Office Practice Naveen Thacker, Niranjan Shendurnikar, Abhay K Shah, Tushar P Shah
Page numbers followed by b refer to box, f refer to figure, and t refer to table.
Abdala 168
Accidental needle stick injuries 82
Acellular pertussis vaccine 18
Acquired immunodeficiency syndrome 75, 121, 188
Acute flaccid paralysis 41
Acute hypersensitivity reaction 41
Acute respiratory distress syndrome 73
Adaptive system 16
Adenovirus vectored vaccines 172
Adult vaccination 63
center, set-up of 48f
Adverse events following immunization 39, 42t, 48
grades of 40t
surveillance system 39
types of 39t
Advisory Committee on Immunization Practices 23, 39, 62, 69, 85, 89, 113, 127, 139, 142, 144, 160
Aedes aegypti 122
Aedes albopictus 122
Alcoholism 88
Allergy 148
Aluminum hydroxide 19
American Diabetes Association 144
Anaphylactoid reaction 41
Anaphylaxis 41
Antibody 16, 168
Antigen 16
presenting cells 16, 189
Anti-pertussis toxin 67
vaccination 121
vaccine 117, 160
Antivaxxers 60
Anxiety 27, 41
Arthritis 176
ASHA workers 62
Asian flu 74
Asplenia 130, 142, 146
congenital 88
Association of Physicians of India 78, 92, 128, 150
Asthma 88, 144
Astrazeneca vaccine 167, 180
Autonomy 61
Bacillus Calmette-Guérin 17, 19, 31, 33, 41, 188
B-cells 16
Biomedical Waste Management Rules 28, 28t
Bleeding disorder 142, 148
Blood products, antibody-containing 146
Body mass index 21
Bone marrow transplant 142
Bordetella pertussis 190
Bronchial asthma 78
Cancer 78, 188
chemotherapy 145
Cansino vaccine 167, 171173
Cardiomyopathies 88
Cell culture vaccines 118
Centers for Disease Control and Prevention 24, 59, 114, 123, 129, 150, 159, 176
Central Bureau of Health Intelligence 67
Cerebrospinal fluid leak 88
Cervical cancer 12, 105
Chemotherapy 142
Chickenpox 4, 9, 109, 112
infection 109
Chinese hamster ovary cells 168
Cholera 127, 158
public health impact of 130
vaccine 131, 160
Chronic obstructive pulmonary disease 12, 78, 88, 142, 144
Cirrhosis 88
Coadministered vaccine 21
Cold chain 30
components of 31
maintenance 30
Common cold 73
Complement deficiencies 88
Conjugate pneumococcal vaccine 87
Continuous temperature recording devices 37
Corbevax 168170, 173
Coronavac 166, 180
Coronavirus disease 2019 (COVID-19) 9, 47, 151, 158, 165, 172, 174178
infection 180
pandemic 3, 9, 22, 24, 45, 47, 50, 53, 56, 58, 61
spread 22
vaccination 22, 45, 59, 60, 61, 78, 155, 161, 165, 170, 172, 172b, 174178, 184, 185
guideline 161
vaccine 45, 141, 169171, 173179, 181, 182, 184, 186
booster doses of 182, 183
composition 186
contraindications of 176
development of 165
side effects of 170
Covavax 173
Covaxin 166, 169, 170, 173, 174, 180, 181
Covishield 167, 169171, 173, 176, 177, 181
Covovax 168
Cowpox 59
Cuba's abdala 168
Curevac vaccine 167, 171
Cytokines 16
Cytolytic molecules 16
Damage-associated molecular patterns 170
Danger signals 16
Death 41
Delta variants 179, 182
Dengue 123
fever 122
infections 122
vaccine 122125, 139, 140
position of 126
Dengvaxia 123, 140
efficacy of 123
Deoxyribonucleic acid 16
vaccines 125, 166
Diabetes mellitus 12, 78, 88
Digital data loggers 37
Digital maximum-minimum thermometers 36, 37f
Diphtheria 9, 67, 68
and tetanus 18, 33, 35
pertussis, and tetanus 9, 33, 35, 60, 67, 138
and tetanus vaccine 67
Ebola virus 18, 165
Emergency use authorization 165, 169
Empathy 55
Emphysema 88
Encephalitis 73
Encephalopathy 41
Eosinophils 16
Equine rabies immunoglobulin 119
Escherichia coli 125, 192
Fainting 41
Febrile seizures 41
Fever 42, 176
enteric 9, 13
Filamentous hemagglutinin 70
Flu 73
vaccine 73, 78
Food and Drug Administration 76
Fresh frozen plasma 146
Gamalaya 167, 171, 173
Gastrointestinal system 194
Gender neutral vaccination 108
Geometric mean titers 17, 181
Geriatric Society of India 92
Gluteal muscle 25
Graft versus host disease 145
Granulomatous disease, chronic 88
Guillain-Barré syndrome 22, 78, 172, 173
H1N1 3, 7476
H2N2 74
H3N2 7376
Haemophilus influenzae B 16, 19, 33, 82, 127, 129, 145, 146
Healthcare professional 45, 53, 150
disease 78, 88
failure, congestive 88
Hemagglutinin 74
Hematopoietic stem cell transplantation 145, 192
Hemoglobinopathies 88
Hepatitis 33
A 4, 9, 13, 24, 101, 137, 140, 143, 145, 151
adult 4
vaccination 102, 103
vaccine 11, 35, 101103, 160
virus infection 101, 102, 144
B 9, 11, 24, 27, 28, 137, 143, 145, 151, 152
chronic 86
immunoglobulin 84, 153
infection 4, 81, 82, 84
surface antigen 153
vaccination, current status of 84
vaccine 35, 81, 84, 140, 151, 153t, 189
virus 15, 19, 81, 83, 84, 144
C 27, 28, 81, 137
vaccine, role of 103
Herpes viruses 188
Herpes zoster 5, 13, 113, 114
vaccine, common adverse effects of 114
Hong Kong flu 74
Human cytomegalovirus disease 192
Human immune system 15
Human immunodeficiency virus 27, 28, 75, 88, 105, 112, 121, 142, 151, 188
infection 88
Human papillomavirus 7, 18, 19, 24, 40, 105, 106, 137, 145, 188
infection 9, 105
vaccination 107
vaccine 105107, 139
bivalent 106
Hypertension 88
Hypotonic hyporesponsive episode 41, 42
Immune system 15
pathogenesis of 122
role of 122
Immunity 6
active 15
cell-mediated 16, 110, 143
cellular 16
herd 20, 21f
humoral 16
passive 15
sterile 6
vaccine-induced 178
Immunization 3, 7
adult 46, 57
general aspects of 1
Immunocompetent host 142
A 194
G 67
intravenous 146
M 110
Immunologic memory 18
Immunosuppressive therapy 142
Inactivated influenza vaccine 78
composition of 75
high-dose 75
Inactivated Kolar strain 132
Inactivated polio vaccine 33, 60, 82, 145, 148, 151, 158
Inactivated vaccine 19, 173
platform 166t
Inactivated whole virion vaccines 166
Indian Academy of Pediatrics 4
Indian Association of Occupational Health 93, 150
Indian Council of Medical Research 124, 191
Indian Medical Association 93, 150
Indian Society of Nephrology 93
Infectious diseases 3
Influenza 9, 33, 73, 151
A virus 74, 75
antigenic subtypes of 74t
illness 75
infection 74
prevention of 75
vaccination, benefits of 152
vaccine 73, 7679, 79t, 151
dosage schedule of 76
safety data of 78
A 3, 73
B 73
C 73
importance of 73
Injectable polio vaccine 155
Injection site abscess 41, 42
Innate immune system 16
Innate T-cells 16
Integrated digital thermometer 36
Intensive care unit 178
Intussusception 41
Invasive pneumococcal disease 12, 87, 88b
Isothermic cold boxes 31, 36
J&J 167, 173, 180
Janssen 169, 180
coronavirus disease 2019
(COVID-19) vaccine 167
Japanese encephalitis 19, 127, 131, 132
vaccine 3, 132, 155, 158
Kidney disease 78
chronic 141, 144
Lactation 142
Light-sensitive vaccines 35
Live oral Ty21A typhoid vaccine 96
Live-attenuated vaccine 18, 75, 76, 125, 132, 146
Liver disease 78
chronic 88, 103, 142, 144
Lower respiratory tract infections 12
Lymphadenitis 41
Malaria Policy Advisory Committee 190
Malaria vaccine 190
Malignancies 142
Measles 151
mumps, and rubella 19, 24, 33, 40, 61, 107, 127, 140, 142, 145, 151
vaccine 110, 140, 151
rubella 60, 153
vaccine 158
Meningococcal conjugate vaccine 127, 129
Meningococcal disease 9, 129
prevention 154
Meningococcal meningitis 11
Meningococcal polysaccharide vaccine 130
Meningococcal vaccine 130, 152, 154, 159
recommendation of 130
Microarray patches 195
Micronutrient deficiency 21
Middle east respiratory syndrome coronavirus 165
Misconceptions 53
Moderna 167, 169, 171, 172, 180
Monocytes 16
mRNA vaccines 166, 173
Mucosa-associated lymphoid tissues 193
Mucosal vaccination 193
Multisystem inflammatory syndrome 177
Mumps 151
Mycobacterium tuberculosis 188
Myocarditis 73
Myositis 73
National Action Plan for Dog Mediated Rabies Elimination 121
National Immunization Program 10, 45, 52, 61, 87, 140
National Institute of Allergy and Infectious Diseases 125, 166
National Vaccine Advisory Committee of Centre for Disease Control 28
National Vector Borne Disease Control Program 132
Natural killer T-cells 16, 191
Needle stick injuries 85
Needle-free injector system 169
Neglected tropical diseases 116
Neisseria meningitidis 11, 129, 152, 188
Neuralgia, postherpetic 114
Neuraminidase 74
Neuritis, brachial 41
Neurotropic human varicella-zoster virus 109
Neutrophils 16
Nonsteroidal anti-inflammatory drugs 177
Northern hemisphere pattern 74, 77f
Novavax 168, 173, 180
Omicron variants 179, 182, 185
O-phthaldialdehyde 90
Oral immunization, limitations of 194
Oral polio vaccine 33, 60, 146, 160
bivalent 158
Oral typhoid vaccine 146
Osteitis 41
Osteomyelitis 41
Papillomatosis, respiratory 106
Paratyphoid vaccine 191
Passive immunization 119
Pathogen-associated molecular patterns 170
Pertussis 9, 67, 68, 151, 188
Pfizer 167, 169, 171, 172, 180
Phagocytic disorders 88
Plasmodium falciparum 190
Pneumococcal conjugate vaccine 88, 143, 145
Pneumococcal disease 9, 12
Pneumococcal infection 87
Pneumococcal pneumonia 5
Pneumococcal polysaccharide 148
vaccine 88
Pneumococcal vaccination 93
Pneumococcal vaccine 12, 87, 89, 92, 93
Pneumonia, community-acquired 90
Polio 151, 158
vaccine 160
Poliomyelitis, inactivated 107
Polysaccharide 18
conjugated 18
Postexposure prophylaxis 117, 119t
Posthematopoietic stem cell transplantation 145t
Pregnancy 142
Protein 18
subunit vaccines 166, 168, 173
Pseudomonas aeruginosa 96
Public health disease surveillance 8
Quadrivalent vaccine 107
Rabies 9, 116, 151
exposure, categories of 117t
immunoglobulin 117
monoclonal antibody 117
passive immunization 119
prophylaxis 117
vaccination 121
vaccine 116, 152, 155, 160, 190, 191
Radiotherapy 142, 145
Randomized controlled trial 90
Recombinant viral vector vaccines 166
Renal disease, chronic 144
Research Society for Study of Diabetes in India 93
Respiratory syncytial virus 22
Reverse transcription polymerase chain reaction 185
Rheumatoid arthritis 175
Rituxan therapy 175
Rituximab 175
Rubella 9, 13, 151
syndrome, congenital 137
Saccharomyces cerevisiae 82
enterica serovar typhi 95
paratyphi 191
typhi 95, 154, 191
Seizures 41, 42
Sepsis 41
Severe acute respiratory syndrome coronavirus 2 4, 19, 175
virus 24, 165, 185
Sexually transmitted infection 105
flexneri 192
sonnei 192
Shingles 9
Sickle cell disease 88
Sinopharm 166, 171, 174, 184
Sinovac 166, 171, 174
Solid organ transplant 142, 145
Southern hemisphere pattern 74, 77f
Spanish flu 74
Splenectomy 88, 142
Splenic dysfunction 88
Spodoptera frugiperda 76
Sputnik-V 167, 169171, 173, 180
Staphylococcus aureus 192
Stem thermometer 36
Steroids 142
Streptococcus pneumococci 87
Streptococcus pneumoniae 12, 73, 87, 143, 188
Swine flu 74
Sympathy 55
Systemic inflammatory response syndrome 73
T-cells 16, 83, 122, 189, 191
activation 15
immunity 185
Temperature monitoring devices 36
Tetanus 9, 67, 68
diphtheria, and pertussis 67, 68, 151
vaccine 138, 151
maternal 10
neonatal 10
prophylaxis 71t
toxoid 24, 31, 35, 35, 138
Tetravalent vaccines 76, 193
Thrombocytopenia 41
heparin-induced 176
T-lymphocyte deficiency 88
Toxic shock syndrome 41
Travel medicine 7
Triplex vaccine 192
Trivalent influenza vaccine 76
Tuberculosis 188
Tumor necrosis factor-alpha 171
Typhoid 96, 151
conjugate vaccine 19, 96, 98, 151
fever 95, 99
polysaccharide vaccine 160
vaccination 96
vaccine 9599, 154
Universal Human Pre-Exposure Immunization Against Rabies 12
Universal Immunization Programme 3, 154
route 21
schedule 21
Vaccine 35, 45, 157
administration 23
behavior, spectrum of 62, 63f
carrier 31
reduced pain of 195
system 194, 195
failure 20
general aspect of 1
hesitancy 56
determinants of 62
induced thrombotic thrombocytopenia 172, 173
platforms 166f
preventable diseases 9, 15, 39, 45, 67, 127f, 142, 150, 157
epidemiology of 9
protection, correlate of 20
storage 30
types of 19, 19t, 79
vial monitor 37, 37f
Varicella 4, 13, 109, 151
disease 112
infection 109, 110
vaccine 109, 110, 112, 113, 151
safety profile of 111
virus 6
immunoglobulin 113
virus 109, 140
Vaxchora 130
Vibrio cholerae 130, 196
Viral vector vaccines 125, 167, 173
pros and cons of 173
Whole cell pertussis vaccines 138
Whooping cough 9
World Health Organization 46, 56, 77, 81, 87, 96, 101, 116, 137, 150, 153, 154, 157, 179, 182
categories 117t
World Rabies Day 121
Wound management 71t, 117
Yellow fever 18, 148, 158, 161
vaccination 158, 159
vaccine 159
Zika virus 165
Zoster vaccines 5, 109, 114
types of 114
Zycov-D 168170, 173
Chapter Notes

Save Clear

General Aspects of Vaccines and Immunization
  • Immunization in Adults: Introduction and General Considerations
    T Jacob John
  • Epidemiology of Vaccine-preventable Diseases in Adults in India
    Venkatarao Epari, Sandhya Gupta, Chandrakant Lahariya
  • Essentials of Immunology and Immunization
    Sapan C Pandya, Rutviz Mistry, Meera Shah
  • Vaccine Administration: Principles and Practices
    Niranjan Shendurnikar, Divya Dave
  • Vaccine Storage and Cold Chain Maintenance
    Digant D Shastri
  • Adverse Events Following Immunization and Vaccine Safety
    Abhay K Shah
  • Setting up of Adult Vaccination Center
    Tushar P Shah, Bhavesh Patel
  • Communication and Counseling Adults for Immunization
    Satish V Pandya, Chitra Pandya
  • Ethical Issues in Adult Vaccination
    Tushar P Shah2

3Immunization in Adults: Introduction and General ConsiderationsChapter 1

T Jacob John
Q1. Immunization is widely recognized as a childhood prophylactic medical intervention. Do adults also need immunization?
India's Universal Immunization Programme (UIP), as also the Expanded Programme on Immunization in other countries, targets newborns to 5 years for scheduled immunization with a number of vaccines, but also covers pregnant women for tetanus–diphtheria immunization. This illustrates that selected adults or selected vaccines may be chosen on purpose, for immunization in adults.
Three “emerging infectious diseases” of the last two decades necessitated adult immunization in India. In 2006, India introduced Japanese encephalitis (JE) vaccine into UIP primarily to address large scale outbreaks in Eastern Uttar Pradesh, Assam, and selected districts in a few more States. It was then extended to adults in 2011 onward in Assam since adult JE was found to be common.
In 2009, a pandemic caused by influenza virus A H1N1-pdm09 started in North America and reached India. When H1N1 vaccine became available, it was widely used in health care in India particularly in adults over 60 years. Currently, annual immunization with quadrivalent influenza vaccine (recommended strains of A H1N1; A H3N2; B Victoria; B Yamagata) is regularly offered in many hospitals to senior citizens. It is also to be recommended in pregnant women as it prevents severe disease in them and their infants.
The pandemic of Coronavirus disease of 2019 (COVID-19) broke out in early 2020. In unprecedented speed, vaccines became available by the last quarter of 2020 and the first quarter of 2021. On 3 January 2021, Government of India gave emergency use authorization for adult immunization with either of two vaccines—Covishield and Covaxin.
These three vignettes illustrate that adults also deserve immunization as their risks for disease become recognized and vaccines are available.
Q2. Are not most adults immune to most diseases? Why do they need immunization?
Children can be immunized for they get exposed to many diseases, particularly the childhood cluster of diseases targeted by UIP. All childhood vaccine-preventable diseases and many more are endemic in India and many adults would have been repeatedly exposed to them. Therefore, most adults in India would have acquired immunity to a number of infectious diseases. Yet there are risks of immunity gaps in adults that can be covered with immunization.
The first immunity gap is due to escaping infection as child, and growing up without immunity. JE in Assam illustrated this. Only first infection carries the risk of disease. Once infected, robust immunity develops and consequent protection is lifelong. The natural 4history of polio is similar in that only the very first infection with types 1, 2, or 3 carries the risk of polio paralysis. Since wild polioviruses are highly contagious, no child could escape infection, and all adults were protected. Since JE is mosquito-transmitted, its epidemiology is restricted by the bionomics of vector mosquitos and variations in age distribution can occur.
Hepatitis A infects many, if not most children, but some do escape. One infection provides lifelong immunity. Those who escaped infection in childhood may get infected at any age: Adult hepatitis A can be severe, even leading to liver failure. Those with any chronic liver disease are particularly vulnerable.
Varicella in India occurs in adults in many communities. Consequently, outbreaks in hospital workers are fairly common and it is a wise policy to check during recruitment the past history of chickenpox. Chickenpox in hospital staff is a risk for infection in immune-compromised patients who may have serious consequences, even fatality. Anyone without past experience of chickenpox deserves varicella vaccination, irrespective of age or occupation.
Hepatitis B infection is most often silent; hence history of past illness is no help to distinguish immune from nonimmune. A practical policy is to vaccinate all freshly joining staff and students in medical and nursing establishments. Others also deserve protection.
A second reason for immunity gaps in adults, against endemic diseases, is related to the pathogen changing its antigen profile, which we call “antigenic drift.” Endemic/seasonal influenza A H1N1 and H3N2 develop antigenic drift during prolonged circulation; hence, appropriate strains are chosen by the global influenza control program of the World Health Organization (WHO) for annual vaccination, separately in Southern Hemisphere and Northern Hemisphere. Another peculiarity of influenza immunity is that high levels of humoral immunity are necessary for protection, because spill-over antibodies on nasal and pharyngeal mucosal surfaces are needed for protection from disease. Although infection itself will boost antibody by memory recall, it will take a few days to kick in, whereas the incubation period of influenza is 1 or 2 days—hence reliance on immunological memory alone is insufficient. Adequate level of spill-over antibodies must be ensured prior to exposure for protection, for which purpose high levels of humoral immunity must be maintained always. That is the rationale of annual influenza vaccination.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is similarly highly prone to antigenic drift on account of the emergence of variants of concern. They have the tendency for evasion, or even outright escape, from immunity. Therefore, bolstering immunity levels by way of boosters are necessary—the higher the immunity achieved, the broader its protective effects, as is obvious from vaccine effectiveness observations. Some countries have begun giving second boosters for this reason. What does the future hold? I had predicted, way back in March 2020, that SARS-CoV-2 will become universally endemic, or pan-endemic. Policies of immunization during endemic infection have to be made, but periodic boosters may be one option that must be considered.
The third reason for immunity gap is immune-senescence due to ageing. All adults are not equal, immunologically. It was in 1999 that Indian Academy of Pediatrics adopted the policy that its purview covered all children and adolescents up to and including 18 years. That brought the legal and health care 5definitions of adults close: For us, all 19 years and older are adults. Arbitrarily, we may consider all 19–39 years as young adults; 40–59 as middle-age, and all 60 years and above as senior citizens—sexagenarians (60–69), septuagenarians (70–79), octogenarians (80–89), nonagenarians (90–99), centenarians (100–109), and supercentenarians (all 110 and above).
We have a predominantly young population in India—the median age is about 28 years—which means that 50% of population is below 29 years of age. Those above 80 years are <14,000,000 or about 1% of total population. Infectious diseases take a heavy toll of lives during their productive years of life and after retirement. We must ensure that no adult dies of vaccine-preventable diseases in our country.
Q3. What is immune-senescence and why does ageing cause it?
Ageing process, resulting in blunting of some or several body functions, begins during or after middle age. All organs, systems, and physiological processes, including the immune system undergo ageing.
In response to “nonself” exposure and stimuli, in our context infection, the immune system is called to respond. Defense responses are a continuum of inflammation, innate immunity, and adaptive immunity. Ageing of the inflammatory processes is called inflamm-ageing, which affects innate immunity as well; ageing of adaptive immunity is immune-senescence. The vaccinology of immune-senescence is discussed in another chapter.
While adults would have responded to many locally prevalent infectious agents and have accumulated memory cells and immune memory, immune senescence puts them at a disadvantage. Proportionally, naïve B and T-cells may now be a minority, crowded out by memory cells stimulated by a plethora of past infections. Where infectious diseases are controlled through functional public health system, life expectancy increases.
The capacity to generate new naïve cells would also decline by ageing, putting older adults at much immunological disadvantage. In short, senior citizens are vulnerable to many infections, as if the microbes were “opportunistic” under the circumstances. We should do the opposite and offer vaccine boosters to overcome the immunity gaps due to senescence as best as we can.
Moreover, many adults, middle age onward, have nutritional and metabolic (noncommunicable) diseases or their predisposing factors that may worsen the problems that the immune system has to face. Altogether adults are vulnerable, immunologically speaking, and our expertise must be put to work against those disadvantages.
The importance of individualizing immunizations, from choice of antigens/vaccines to the timing and planning schedules with the number of doses, is our responsibility. Therefore, we need to know the background frequencies of ubiquitous and locality-specific pathogens, the risks of their diseases, the availability of various vaccines, their comparative merits and precautions, in order to serve adults with competence and accountability.
Q4. Why are pneumococcal and zoster vaccines recommended routinely?
Pneumococcal pneumonia and herpes zoster are two diseases illustrating the “opportunism” phenomenon. Immunity against pneumococci wanes due to immune-senescence, and senior citizens are prone to pneumococcal pneumonia. In younger age groups, pneumococcal pneumonia is usually the result of nasopharyngeal infection 6extending down to the alveoli—hence often heralded by upper respiratory symptoms, alerting physicians to examine for pneumonia when symptoms/signs develop. Early diagnosis and correct treatment save lives.
In senior citizens, pneumonia may follow bacteremia without upper respiratory symptoms. Fever and chills give away the clue to bacteremia. Often these are the only symptoms of early pneumonia and physicians are prone to miss the signal. By the time cough and sputum appear, the person would have slipped into multiorgan failure with fatal outcome. All these can be prevented by vaccinating senior citizens. My personal recommendation is for Prevnar 13 followed after 6 months with 23-valent nonconjugated vaccine, once during life.
Varicella virus is well known to set up latent infection in posterior nerve root ganglia. As immunity wanes, the probability of “reactivation” disease—herpes zoster—increases. However, we do not see herpes zoster as often as western country physicians see in their countries. One reason may be that chickenpox in India has an age shift upward and the risk of zoster is partly determined by duration of latent infection. Most persons with past chickenpox may not have lived long enough for high risk of zoster. Our life expectancy at birth is lower than in western countries, and senior citizens (above 60) constitute only 10% of our population, while it is over 20–25% elsewhere. Two zoster vaccines are licensed for use in few countries.
Q5. Are the terms immunization and vaccination synonymous?
The term immunization is taken for granted as synonymous with vaccination in common usage. Strictly speaking they are not synonymous, when we dissect out the meanings of the two words. Vaccination is what we do when we inoculate a vaccine; the effect we desire is induction of immune responses, surrogate for protective immunity. The physiological/immunological process of induction of immune response is the true meaning of immunization. Therefore, we must be reasonably sure that our vaccination results in immunization, for which much knowledge is required about the available vaccines, their epidemiological need in given contexts, safety profile, efficacy range, their benefit–cost consideration, and benefit–risk balance.
Once we understand all such issues, we are justified in using the word immunization for vaccination. So, purposeful vaccination, with good justification, and adequate confidence supported by actual documentation of desired immune response(s), or in its absence by evidence in the medical literature, qualifies for immunization.
Any or all detected immune response(s), and the idea of “immunity” as protection, need not be fully aligned. Immune response(s) that are “protective” against a given disease is the true value of immunity. Technically speaking, the presence of any immune response as detected against selected antigens is also immunity. It may be antibody- or cell-mediated response. Protection in this context, or immunity in the practical sense, has a range of functions. At one end of its spectrum is protection from severe disease threatening fatal outcome—which is the minimum we desire by immunization. At the other extreme end of the spectrum is protection from infection itself. The gradient of benefit lies in between.
The term “sterile immunity” has been used when immunity prevents even the very first event of pathogen entry into a sterile or “prohibited” site in the body, or, the entry of a virus inside a host cell that 7initiates infection. Immunization with human papillomavirus (HPV) vaccine does just that—once immunized, the particular HPV genotype is not allowed cell entry. If even one cervical epithelial cell is infected, the spread to contiguous cells cannot be prevented by immunity. Unlike other viruses, HPV spreads from cell to cell without giving a chance for virus neutralizing antibodies to stop further spread in the intercellular spaces. Vaccine-induced immunity is high enough for spill-over antibodies on the cervix all the time, protecting from infection per se, consequently protection from cancer induced by the genotypes in the vaccine.
Earlier we saw that this principle of sterile immunity is what we aim for, through annual influenza immunization. We need protection from influenza viruses causing infection, for which high levels of humoral immunity must be maintained. Even if “breakthrough” infection occurs, the diseases is rendered mild due to antibodies in body fluids—particularly in intercellular spaces.
Q6. Why should international travelers be vaccinated?
Immunization may play an important role for protecting the health of travelers. The epidemiological basis is simple: Endemic diseases in the country of destination (or transit) may be different from those of the traveler's country of residence. When the travel destination is endemic for vaccine-preventable diseases, the opportunity for protection must not be missed.
Since there is no highly effective vaccine to protect from malaria, antimalarial drugs are recommended when traveling to malaria-prone areas.
When travelling to a country in which yellow fever is prevalent, immunization is important, and even required by international travel regulations and visa approval. For those who travel from places without enzootic and endemic JE to JE-affected countries, pretravel immunization is a good precaution.
In this manner, there is a discipline called “Travel Medicine” and experts will have up-to-date information of the geographic prevalence and risks of various infectious diseases and the availability of various vaccines.
Eating out is either fashion or necessity these days—and food-borne infectious diseases are notorious in this context. All food-handlers—in road-side eateries to five-star hotels and everything in between—ought to be vaccinated against certain food-related infectious diseases and their microbial infections. Typhoid and hepatitis A immunizations are particularly relevant for both groups of people on either side of the food counter–those who cater and those who consume. International travelers going to countries where either or both are endemic should be up-to-date with their immunization.
Q7. Should there not be a national program for adult immunization?
Immunization makes use of a pharmaceutical tool—shared by individualized healthcare and also programmed immunization in public health.
Healthcare is the “felt need” of everyone who feels ill. The healthcare system is approached by the individual for diagnosis and treatment. The physician can/must take an extra step and consider immunization as “preventive medicine.”
The idea of “family practice” or “general practice” is for long-term care of members of families, or individuals, who ought to return to the same clinic repeatedly and not change clinics such as “shopping around.” In family and general practice, medical records should 8be maintained long term and the physician should give timely advice for immunization when relevant, on the basis of the several criteria described in this and other chapters in this book.
In healthcare, various specialty departments will immunize those who come under their care—obstetricians will immunize pregnant women; transplant experts will immunize transplant recipients according to protocol; oncologists will do likewise for those with malignancies on therapy.
Public health is the “art and science of disease prevention and health promotion” among citizens. Adult immunization in clinical practice is not a substitute for the government using immunization as a tool for prevention of diseases in the citizens. Unfortunately, India does not have a public health division in the government and for that reason no platform to make and implement policies on adult immunization.
When our government establishes a public health division, hopefully earlier than later, the entire gamut of health promotion and disease prevention can be systematized and reduction of disease frequencies monitored through reliable counting processes. This is known as “public health disease surveillance.” Once public health division is functional, UIP can be subsumed in it and the purview of immunization expanded to adults.
When immunization is brought under public health, the fall in disease burden may be higher than what may be accounted for by immunization coverage alone. This phenomenon is called “herd effect” while actual coverage achieves “herd immunity.” In simplified language, the proportion with immunity is herd immunity—infection-induced and immunization-induced immunity. The fall in disease incidence among the unimmunized on account of high herd immunity achieved through immunization is herd effect. The importance of these issues is related to “socio-economic development” of the nation.
When immunization is utilized maximally, healthcare centers will be uncluttered of vaccine-preventable diseases. Families will not need to spend money for treatment of vaccine-preventable diseases. Employed persons will not lose working days to diseases, and national productivity will increase. Professional practice of adult immunization added on the UIP platform is our contribution to nation building.
  1. Anonymous. Guidelines for vaccination in normal adults in India. Indian J Nephrol. 2016;26(Suppl 1):S7-14.
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