What is a vaccine?
A: A vaccine is a biological preparation that provides active acquired immunity to a particular
A vaccine typically contains an agent that resembles what?
A: A disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins, or one of its surface proteins.
The agent stimulates the body's immune system to recognize the agent as a what?
A: A threat, and to further recognize and destroy any of the microorganisms associated with that agent that it may encounter in the future.
The administration of vaccines is called what?
Vaccination is the most effective method of preventing what?
A: Infectious diseases.
Widespread immunity due to vaccination is largely responsible for the worldwide eradication of what disease?
It is also responsible for the restriction of diseases such as what?
measles, and tetanus from much of the
The effectiveness of vaccination has been widely studied and what?
A: Verified; for example, vaccines that have proven effective include the influenza vaccine, the HPV vaccine, and the chicken pox vaccine.
The World Health Organization (WHO) reports that licensed vaccines are currently available for how many different preventable infections?
The terms vaccine and vaccination are derived from what?
A: Variolae vaccinae (smallpox of the cow), the term devised by Edward Jenner to denote cowpox.
He used it in 1798 in the long title of his Inquiry into the Variolae vaccinae known as the Cow Pox, in which he described what?
A: The protective effect of cowpox against smallpox.
In 1881, to honor Jenner what did Louis Pasteur propose?
A: That the terms should be extended to cover the new protective inoculations then being developed.
There is overwhelming scientific consensus that vaccines are a very safe and effective way to do what?
A: Fight and eradicate infectious diseases.
Sometimes, protection fails because the host's immune system simply does not what?
A: Respond adequately or at all.
Lack of response commonly results from clinical factors such as what?
A: Diabetes, steroid use, HIV infection, or age.
It also might fail for genetic reasons if the host's immune system includes what?
A: No strains of B cells that can generate antibodies suited to reacting effectively and binding to the antigens associated with the pathogen.
Even if the host does develop antibodies, protection might not be adequate; immunity might develop how?
A: Too slowly to be effective in
time, the antibodies might not disable the pathogen completely, or there might be multiple strains of the pathogen, not all of which are equally susceptible to the immune reaction.
However, even a partial, late, or weak immunity, such as a one resulting from cross-immunity to a strain other than the target strain, may do what?
A: Mitigate an infection, resulting in a lower mortality rate, lower morbidity, and faster recovery.
Adjuvants commonly are used to do what?
A: To boost immune response, particularly for older people (50–75 years and up), whose immune response to a simple vaccine may have weakened.
Maurice Hilleman's measles vaccine is estimated to prevent how many deaths every year?
A: 1 million.
If a vaccinated individual does develop the disease vaccinated against (breakthrough infection), the disease is likely to be what?
A: Less virulent than in unvaccinated victims.
In 1958, there were 763,094 cases of measles in the United States resulting in how many deaths?
A: 552 deaths resulted.
After the introduction of new vaccines, the number of cases dropped to how many per year?
A: Fewer than 150.
In early 2008, there were how many suspected cases of measles?
Fifty-four of those infections were associated with what?
A: Importation from another country, although only 13% were actually acquired outside the United States.
63 of the 64 individuals either had never been vaccinated against measles or were what?
A: Uncertain whether they had been vaccinated.
Other diseases such as rubella, polio, measles, mumps, chickenpox, and typhoid are nowhere near as common as they were a hundred years ago thanks to what?
A: Widespread vaccination programs.
As long as the vast majority of people are vaccinated, it is much more difficult for what to happen?
A: For an outbreak of disease to occur, let alone spread.
This effect is called what?
A: Herd immunity.
Polio, which is transmitted only between humans, is targeted by an extensive eradication campaign that has seen endemic polio restricted to only parts of what three countries?
A: Afghanistan, Nigeria, and Pakistan.
However, the difficulty of reaching all children as well as cultural misunderstandings have caused the anticipated eradication date to be what?
A: Missed several times.
Vaccines also help prevent the development of what?
A: Antibiotic resistance.
Vaccination given during childhood is what?
A: Generally safe.
Adverse effects, if any, are generally what?
The rate of side effects depends on what?
A: The vaccine in question.
Some common side effects include what?
A: Fever, pain around the injection site, and muscle aches.
Additionally, some individuals may be what?
A: Allergic to ingredients in the vaccine.
MMR vaccine is rarely associated with what?
A: Febrile seizures.
Severe side effects are extremely what?
Some countries such as the United Kingdom provide what for victims of severe adverse effects via its Vaccine Damage Payment?
Some vaccines contain what?
A: Live, attenuated microorganisms.
Many of these are active viruses that have been cultivated under conditions that do what?
A: Disable their virulent properties, or that use closely related but less dangerous organisms to produce a broad immune response.
Although most attenuated vaccines are viral, some are what?
A: Bacterial in nature.
Examples include what viral diseases?
A: Yellow fever, measles, mumps, and rubella, and the bacterial disease typhoid.
The live Mycobacterium tuberculosis vaccine developed by Calmette and Guérin is not made of a contagious strain but contains a what?
A: A virulently modified strain called "BCG" used to elicit an immune response to the vaccine.
The live attenuated vaccine containing strain Yersinia pestis EV is used for what?
A: Plague immunization.