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ACIP: Advisory Committee on Immunization Practices

AID: activation-induced cytidine deaminase

APC: antigen-presenting cell

ASD: autism spectrum disorder

BCG: bacille Calmette-Guérin

BCR: B-cell receptor

CDC: Centers for Disease Control and Prevention

CoP: correlate of protection

COVID-19: coronavirus disease 2019

CRM: cross-reactive material

DTaP: diphtheria and tetanus toxoids and acellular pertussis

EBOV: Zaire ebolavirus, Ebola virus

EMA: European Medicines Agency

EUA: Emergency Use Authorization

Fab: fragment, antigen-binding

Fc: fragment crystallizable

GBS: Guillain-Barré syndrome

GPCR: G protein-coupled receptor

H1N1: hemagglutinin subtype 1 and neuraminidase subtype 1

H3N2: hemagglutinin subtype 3 and neuraminidase subtype 2

HA: hemagglutinin

Hib: Haemophilus influenzae type b

HIV: human immunodeficiency virus

HPV: human papillomavirus

Ig: immunoglobulin

IIV: inactivated influenza vaccine

IOM: Institute of Medicine (now National Academy of Medicine)

IPV: inactivated poliovirus (vaccine)

JE: Japanese encephalitis

mCoP: mechanistic correlate of protection

MeV: measles virus

MMR: measles-mumps-rubella

MMRV: measles-mumps-rubella-varicella

mAbs: monoclonal antibodies

mRNA: messenger RNA

nCoP: nonmechanistic correlate of protection

PCV: pneumococcal conjugate vaccine

PRP: polyribosylribitol phosphate

RBD: receptor binding domain

RSV: respiratory syncytial virus

SAE: serious adverse event

SARS-CoV-2: severe acute respiratory syndrome coronavirus 2

SIDS: sudden infant death syndrome

TB: Mycobacterium tuberculosis

Td: tetanus toxoid and reduced diphtheria toxoid

Tdap: tetanus toxoid, reduced diphtheria toxoid, acellular pertussis

VZV: varicella-zoster virus

WHO: World Health Organization


The historical impact of infectious diseases is evident in the high mortality rates in young children and adults and the disruption that these diseases have caused in emerging societies. The rise of civilization in conjunction with the domestication of plants and animals permitted people to live in denser communities with each other and with their animals. Such proximity provided ideal breeding grounds for infectious pathogens, and their spread resulted in epidemics throughout the world. As people began to question the underlying causes of disease and the apparent protection to reinfection afforded to some survivors of a disease, ideas of immunity and disease prevention were born, apparently as early as the 5th century.

The concept of immunity goes back at least to the 17th century when emperor K’ang of China documented his practice of variolation, or inoculation, of his troops and his own children with smallpox to confer protection from the disease (Hopkins, 2002). Variolation involved taking liquid from a smallpox pustule of an infected patient, cutting the skin of an uninfected person, and then introducing the inoculum. Records from the 18th century note that enslaved Africans brought to the U.S. bore scars from smallpox variolation and were thought to be immune to the disease. Variolation against smallpox was also reported by Lady Mary Montagu during her time in Constantinople (1716–1718). Lady Montagu, herself a survivor of smallpox, reported that certain Turkish women would open a wound in healthy individuals and introduce the contents of a smallpox vesicle with a large needle, thereby providing a level of protection against smallpox. About 2% to 3% died after variolation, whereas 20% ...

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