In order for vaccines to protect everyone, an estimated 85 to 95 percent of the population must
be immunized. Studies have shown that children who are not immunized are more likely
to become infected with measles and pertussis. Younger children often are the most
vulnerable; 90 percent of deaths from pertussis are in infants younger than 6 months old.
It is not advisable to skip or delay vaccines, as this will leave the child vulnerable to disease for
a longer period of time. Parents should follow the immunization schedule provided by the
CDC and its Advisory Committee on Immunization Practices, the AAP, and the American
Academy of Family Physicians (AAFP) each year. This schedule is designed by experts
to ensure maximum protection and safety for children at various ages. Parents should
discuss any concerns with their child’s pediatrician.
Serious events occur more often from the actual infection or disease, rather than from the
vaccine; therefore, the vaccine is much safer.
PERTUSSIS
Recently, there have been outbreaks of pertussis (also know as whooping cough) in various
areas of the United States. Pertussis is particularly dangerous to infants who are too young to
receive the DTaP vaccine. At least six babies have died during these outbreaks. Experts are
recommending “cocooning,” a strategy that protects infants who are too young to be immunized,
by having parents, siblings, and caretakers vaccinated against this disease. People over 11 years
of age (and those over 7 in some states with outbreaks) should receive 1 dose of Tdap vaccine if
they have not already.
The Disease
If you've ever seen a child with pertussis you, won't forget it. The child coughs violently and
rapidly, over and over, until the air is gone from his/her lungs and he/she is forced to inhale with
the loud "whooping" sound that gives the disease its nickname, Whooping Cough. Then the
coughing begins again. These severe coughing spells can go on for weeks. The child might turn
blue from lack of air, or vomit after a coughing spell. A child with Whooping Cough can have
difficulty eating, drinking, or even breathing.
The Immunization
The first pertussis vaccine was developed in the 1930's, and became widely used by the 1940's.
In the early 1990's a new "acellular" pertussis vaccine was licensed, which works as well as the
original vaccine but has fewer side effects.
Recently a second pertussis vaccine, Tdap, was added to the schedule for adolescents. It is
recommended that adolescents receive this vaccine instead of Td so that they continue to be
protected against Whooping Cough.
Tetanus:
The Disease
Tetanus enters the body through cuts in the skin. It can get in through even a tiny pinprick or
scratch, but it prefers deep puncture wounds or cuts, like those made by nails or knives. Children
can also get tetanus following severe burns, ear infections, tooth infections, or animal bites. Rusty
nails are often blamed for causing tetanus, but is the tetanus bacteria, and not rust, that causes
the disease. You can get tetanus from a shiny nail as easily as from a rusty one.
The Immunizaton
As with the diphtheria vaccine, tetanus vaccine is really a toxoid, which protects against the toxin
produced by tetanus bacteria.
Recently a second tetanus vaccine, Tdap, was added to the schedule for adolescents. It is
recommended that adolescents receive this vaccine instead of Td.
Diphtheria used to be a major cause of childhood illness and death. Through the 1920's about
150,000 people got diphtheria each year in the United States and about 15,000 of them died. The
word diphtheria struck fear into the hearts of parents in those days, but today there are only a few
cases a year. This change is due largely to our parents and grandparents, who got their children
immunized.
DTaP Side effects:
Mild Problems (Common)
Fever (up to about 1 child in 4)
Redness or swelling where the shot was given (up to about 1 child in 4)
Soreness or tenderness where the shot was given (up to about 1 child in 4)
These problems occur more often after the 4th and 5th doses of the DTaP series than after
earlier doses. Sometimes the 4th or 5th dose of DTaP vaccine is
followed by swelling of the entire arm or leg in which the shot was given, lasting 1-7 days (up to
about 1 child in 30).
Other mild problems include:
Fussiness (up to about 1 child in 3)
Tiredness or poor appetite (up to about 1 child in 10)
Vomiting (up to about 1 child in 50)
These problems generally occur 1-3 days after the shot.
Moderate Problems (Uncommon)
Seizure (jerking or staring) (about 1 child out of 14,000)
Non-stop crying, for 3 hours or more (up to about 1 child out of 1,000)
High fever, over 105°F (about 1 child out of 16,000)
Severe Problems (Very Rare)
Serious allergic reaction (less than 1 out of a million doses)
Several other severe problems have been reported
after DTaP vaccine. These include:
o Long-term seizures, coma, or lowered consciousness
o Permanent brain damage.
These are so rare it is hard to tell if they are caused
by the vaccine.
Polio:
The Disease
Polio was one of the most dreaded childhood diseases of the 20th Century in the United States.
An epidemic in 1916 killed 6,000 people and left 27,000 more paralyzed. In the 1950's, parents
refused to let their children go to movies or go swimming for fear of catching the disease.
The Immunization
There are two types of polio vaccine: Inactivated (killed) polio vaccine (IPV), which is a shot; and
live oral polio vaccine (OPV), which is a liquid that is swallowed. In the US, only the IPV is used.
Inactivated Polio Vaccine (IPV) can prevent polio.
History: A 1916 polio epidemic in the United States killed 6,000 people and paralyzed 27,000
more. In the early 1950’s there were more than 20,000 cases of
polio each year. Polio vaccination was begun in 1955. By 1960 the number of cases had dropped
to about 3,000, and by 1979 there were only about 10. The
success of polio vaccination in the U.S. and other countries sparked a world-wide effort to
eliminate polio.
Today: No wild polio has been reported in the United States for over 20 years. But the disease is
still common in some parts of the world. It would only take one
case of polio from another country to bring the disease back if we were not protected by vaccine.
If the effort to eliminate the disease from the world is successful,
some day we won’t need polio vaccine. Until then, we need to keep getting our children
vaccinated.
These people should not get IPV:
Anyone who has ever had a life-threatening allergic reaction to the antibiotics neomycin,
streptomycin or polymyxin B should not get the polio shot.
Anyone who has a severe allergic reaction to a polio shot should not get another one.
These people should wait:
Anyone who is moderately or severely ill at the time the shot is scheduled should usually wait
until they recover before getting polio vaccine. People with
minor illnesses, such as a cold, may be vaccinated.
Ask your health care provider for more information.
What are the risks from IPV?
Some people who get IPV get a sore spot where the shot was given. The vaccine used today has
never been known to cause any serious problems, and most
people don’t have any problems at all with it.
However, a vaccine, like any medicine, could cause serious problems, such as a severe allergic
reaction. The risk of a polio shot causing serious harm, or death,
is extremely small.
Recent News About Polio: In Tajikistan at least 128 cases of acute flaccid paralysis had been
reported in Tajikistan by April 22, and 10 of the infected children had died. However, the polio
virus was detected in only seven of these cases, according to the WHO report. Uzbekistan has
also reported three cases of AFP.
Outbreak confirmed by WHO
A team of six WHO experts are in the country to work with the
Tajik national health authorities. The outbreak was confirmed by tests conducted at the WHO
Collaborating Center in Moscow.
“This is the first importation of polio in the European region since Europe was certified as poliofree in 2002,” noted Sona Bari, a spokesperson for the WHO Polio Eradication Initiative on
Monday. She added that three large-scale vaccination campaigns are being carried out and are
expected to reach some 864,000 children under age five. Bari added that genetic sequencing is
under way to identify the origin of the outbreak. Routine immunization in Tajikistan is around 87
percent, she noted; however, “there are sub-pockets in all countries, including remote rural areas,
which are less well-vaccinated than others.”
HIB:
The Disease
You may never have heard of Haemophilus influenzae type b, or "Hib" disease. For some reason
Hib disease has never become as well known as other childhood diseases, but it is just as
dangerous. As recently as the mid-1980's, Hib disease struck one child out of 200 under 5 years
old in the United States. Every year about 12,000 children got meningitis (inflammation of the
covering of the brain) as a result of Hib. In fact, Hib disease was the leading cause of bacterial
meningitis in children under five. About 1 in 4 of these children suffered permanent brain damage,
and about 1 in 20 died. In addition, about 8,000 children a year suffered from other serious
complications, such as pneumonia.
The Immunization
Hib vaccine has had a dramatic impact on Haemophilus influenzae type b. As soon the first
vaccine came into use in 1985, the disease began to disappear. Several improved vaccines have
been licensed since then, and the age for the first shot has been lowered from 24 months to 2
months. There were an estimated 20,000 cases of Hib disease a year in the mid-1980's, but now
there are only a few hundred cases a year.
Before Hib vaccine, Hib disease was the leading cause of bacterial meningitis among children
under 5 years old in the United States. Meningitis is an infection of
the brain and spinal cord coverings, which can lead to lasting brain damage and deafness. Hib
disease can also cause:
pneumonia
severe swelling in the throat, making it hard to breathe
infections of the blood, joints, bones, and covering of the heart
death
Risk from Hib vaccine:
A vaccine, like any medicine, is capable of causing serious problems, such as severe allergic
reactions. The risk of Hib vaccine causing serious harm or death is
extremely small.
Most people who get Hib vaccine do not have any problems with it.
Mild Problems
Redness, warmth, or swelling where the shot was given (up to 1/4 of children)
Fever over 101°F (up to 1 out of 20 children)
If these problems happen, they usually start within a day of vaccination. They may last 2-3 days.
Some specifics: Before Hib vaccine became available, there were approximately 20,000 cases
annually. Hib was the most common cause of bacterial meningitis in children in the U.S.
Hib meningitis once killed 600 children each year in this country, and those who survived
often had deafness, seizures and/or mental retardation.
Hep A:
The Disease
Hepatitis A is a serious disease that causes liver inflammation. It is caused by the hepatitis A
virus , which is found in the stool of persons with hepatitis A. It is usually spread by close
personal contact and sometimes by eating food or drinking water that has been contaminated.
The Immunization
You can protect children from hepatitis A by getting them vaccinated with two doses of hepatitis A
vaccine. It is recommended that children receive their first dose between 12-23 months of age,
although the vaccine can be given at later visits. The second dose of vaccine should be given at
least 6 months following the first dose.
Hep B:
The Disease
Hepatitis B is a disease that affects the liver. It is one of several hepatitis diseases (for example,
hepatitis A and hepatitis C). These are caused by different germs, but are similar in that they all
affect the liver ("hepatitis" comes from the Greek words for "liver" and "inflammation").
About 1.25 million people in the U.S. have chronic HBV infection. Hepatitis B virus is spread
through contact with the blood and body fluids of an infected person.
A person can get infected in several ways, such as:
by having unprotected sex with an infected person
by sharing needles when injecting illegal drugs
by being stuck with a used needle on the job
during birth when the virus passes from an infected mother to her baby
About 1/3 of people who are infected with hepatitis B in the United States don’t know how they
got it.
The Immunization
You can protect children from hepatitis B by getting them vaccinated with three doses of hepatitis
B vaccine. Newborn babies whose mothers either are infected with the hepatitis B virus or have
not been tested should get their first shot within 12 hours of birth, the second shot at 1-2 months
of age, and the third shot at 6 months of age. Other babies can get their first shot between birth
and 2 months of age, the second at 1-4 months of age, and the third at 6-18 months of age.
Why get vaccinated?
Hepatitis B vaccine can prevent cancer. It is the first anti-cancer vaccine because it can
prevent a form of liver cancer.
Each year it is estimated that:
80,000 people, mostly young adults, get infected with HBV
More than 11,000 people have to stay in the hospital because of hepatitis B
4,000 to 5,000 people die from chronic hepatitis B
What are the risks from Hepatitis B vaccine?
Mild problems
soreness where the shot was given, lasting a day or two (up to 1 out of 11 children and
adolescents, and about 1 out of 4 adults)
mild to moderate fever (up to 1 out of 14 children and adolescents and 1 out of 100 adults)
Severe problems
serious allergic reaction (very rare)
HPV:
The Disease
Genital human papillomavirus (HPV) is the most common sexually transmitted virus in the US.
More than 50% of sexually active men and women are infected with HPV at some time in their
lives. There are about 40 different types of HPV that can cause infection. Some types can cause
serious health problems such as cervical cancer in women, other cancers in the genital area in
women and men, and genital warts in women and men.
The Immunization
HPV vaccine can prevent most genital warts and most cases of cervical cancer. HPV vaccine is
routinely recommended for girls in a 3-dose series. The first dose is given at 11-12 years of age,
a second dose is given 2 months after the first dose, and a 3rd dose is given approximately 4
months later. The vaccine is also recommended for girls and women 13-26 years of age who did
not receive it when they were younger.
Measels:
The Disease
Not everyone recognizes measles as the serious disease it really is, possibly because it used to
be a routine part of everyone's childhood, and also because we don't see it nearly as much as we
used to. But measles can be deadly. The 10th Century Persian physician Rhazes considered
measles "more to be dreaded than smallpox." Measles still kills about a million people a year
around the world. Measles can also make a pregnant woman have a miscarriage or give birth
prematurely.
Measles
Measles virus causes rash, cough, runny nose, eye irritation, and fever.
It can lead to ear infection, pneumonia, seizures (jerking and staring), brain damage, and
death.
The Immunization
Measles vaccine was licensed in 1963. As children started getting the vaccine, measles quickly
began to disappear. Today we see only about a hundred cases a year.
What are the risks from MMR vaccine?
causing serious problems, such as severe allergic reactions. The risk of MMR vaccine causing
serious harm, or death,
is extremely small. Getting MMR vaccine is much safer than getting any of these three diseases.
Most people who get MMR vaccine do not have any problems.
Mild Problems
Fever (up to 1 person out of 6)
Mild rash (about 1 person out of 20)
Swelling of glands in the cheeks or neck (rare)
If these problems occur, it is usually within 7-12 days after the shot. They occur less often after
the second dose.
Moderate Problems
Seizure (jerking or staring) caused by fever (about 1 out of 3,000 doses)
Temporary pain and stiffness in the joints, mostly in teenage or adult women (up to 1 out of 4)
Temporary low platelet count, which can cause a bleeding disorder (about 1 out of 30,000
doses)
Severe Problems (Very Rare)
Serious allergic reaction (less than 1 out of a million doses)
Several other severe problems have been known to occur after a child gets MMR vaccine. But
this happens so rarely, experts cannot be sure whether
they are caused by the vaccine or not. These include:
o Deafness
o Long-term seizures, coma, or lowered consciousness
o Permanent brain damage
Measles is another example of a vaccine-preventable disease with serious consequences.
Currently in the U.S., up to 20 percent of people with measles are hospitalized. This is one of the
most infectious diseases in the world; if vaccinations were stopped, each year about 2.7 million
deaths from measles worldwide could be expected. A recent outbreak of measles in San Diego,
California, 11 children contracted measles and none had been vaccinated. This is the highest
number of measles cases San Diego has seen in 17 years. It is believed to have started with a
child who caught measles in Switzerland and then returned to the U.S.
Mumps:
The Disease
Before vaccines, mumps was a common childhood disease. The most obvious sign of mumps is
swelling of the cheeks and jaw, which is caused by inflammation in the salivary glands. Children
with mumps usually also get a fever and headache. Generally, mumps is a mild disease, but it
does have its serious side.
Mumps
Mumps virus causes fever, headache, and swollen glands.
It can lead to deafness, meningitis (infection of the brain and spinal cord covering), painful
swelling of the testicles or ovaries, and, rarely, death.
Measles
Measles virus causes rash, cough, runny nose, eye irritation, and fever.
It can lead to ear infection, pneumonia, seizures (jerking and staring), brain damage, and
death.
The Immunization
The mumps vaccine we use today was licensed in 1967, and is a live, attenuated (weakened)
vaccine. The number of reported cases has dropped from over 150,000 in 1968 to only 666 in
1998.
Rubella:
The Disease
When children get rubella, it is usually a mild disease with a slight fever that lasts for about 24
hours and a rash on the face and neck that lasts two or three days.
The Immunization
Rubella vaccine was first licensed in the U.S. in 1969, and the vaccine we use today was licensed
in 1979. It is a live, attenuated (weakened) vaccine.
Meningocoocal
The Disease
Meningitis is an infection of the spinal cord and fluid surrounding the brain. Meningococcal
disease also causes blood infections. Children and young adults, particularly college freshmen
who live in dormitories, are most often affected by meningococcal disease, but persons of any
age can become infected. There are 2 types of meningococcal disease: bacterial and viral.
Severity of the disease and treatment depend on which type a person has.
Meningococcal disease is a severe bacterial infection that can cause meningitis, bloodstream
infection, and other localized infections. Although the disease is not
common in the United States, in those who get it, symptoms develop and progress rapidly even
leading to death in 24-48 hours.
The Immunization
There are 2 types of meningococcal vaccine. Meningococcal polysaccharide vaccine (MCV4) is
routinely recommended for all 11 and 12 year olds, and for children over 12 who have not
received the vaccine previously. MCV4 is preferred for people aged 11-55, as well as certain high
risk children from the ages of 2-10. The meningococcal polysaccharide vaccine (MPSV4) vaccine
is recommended for certain older populations.
What are the risks from meningococcal vaccine?
Up to about half of people who get meningococcal vaccines have mild side effects, such as
redness or pain where the shot was given. If these problems occur,
they usually last for 1 or 2 days. Mild side effects are more common after MCV4 than after
MPSV4. A small percentage of people who receive the vaccine
develop a fever. Serious allergic reactions, within a few minutes to a few hours of the shot, are
very rare.
Pneumococcal
The Disease
The Streptococcus pneumoniae bacteria kills more people in the United States each year than all
other vaccine-preventable diseases combined (about 40,000). It is commonly thought of as a
disease of the elderly, but it also takes its toll among our children. It is the leading cause of
bacterial meningitis in the country, hitting children under one year old the hardest. About 200
children die from invasive pneumococcal disease each year.
What is Pneumococcal Disease?
Infection with Streptococcus pneumoniae bacteria can cause serious illness and death. Invasive
pneumococcal disease is responsible for about 200 deaths each
year among children under 5 years old. It is the leading cause of bacterial meningitis in the United
States. (Meningitis is an infection of the covering of the brain).
Each year pneumococcal infection causes severe disease in children under five years old:
Over 700 cases of meningitis
13,000 blood infections
About 5 million ear infections
It can also lead to other health problems, including:
Pneumonia
Deafness
Brain damage
The Immunization
Until 2000, pneumococcal vaccine was recommended mostly for adults over 65 years old, and
was not licensed at all for children under 2. This is because the only type of vaccine that was
available (pneumococcal "polysaccharide" vaccine) doesn't work very well for young children. In
2000, a different type of vaccine (pneumococcal "conjugate" vaccine- PCV7) was licensed that
works for children under 2, and it was finally possible to prevent pneumococcal disease in this
vulnerable age group. In 2010, a new version of the pneumococcal conjugate vaccine (PCV13)
was approved that protects against even more strains of pneumococcal disease.
What are the risks from pneumococcal vaccine?
In studies reviewing nearly 60,000 doses, pneumococcal conjugate vaccine was associated with
only mild reactions:
About 1 infant out of 4 had redness, tenderness, or swelling where the shot was given.
About 1 out of 3 had a fever of over 100.4°F, and about 1 in 50 had a higher fever (over
102.2°F) - usually within the first 1-2 days after injections.
Some children also became fussy or drowsy, or had a loss of appetite.
So far, no serious reactions have been associated with this vaccine.
Rota:
The Disease
Rotavirus is the most common cause of diarrhea and vomiting in infants and young children. In
fact, most children get rotavirus sometime before they are 5 years old. While many children have
mild cases, others can get very sick.
The Immunization
Rotavirus vaccine is an oral (swallowed) vaccine, not a shot. The vaccine has 2-3 doses that are
given by mouth at 2 months and 4 months of age. Another dose at 6 months of age may be
needed depending on the brand of vaccine used. Rotavirus vaccine will not prevent diarrhea or
vomiting caused by other germs, but it is good at preventing diarrhea and vormiting caused by
rotavirus.
Varicella:
The Disease
Varicella, or chickenpox, is one of the most common childhood diseases. It is caused by the
varicella-zoster virus. Most people in the United States get chickenpox while they are still
children. Until the late 1990's there were about 4 million cases a year. But now that people are
using varicella vaccine, that number has begun to drop.
What is Chickenpox?
Chickenpox (also called varicella) is a common childhood disease. It is usually mild, but it
can be serious, especially in young infants and adults.
The chickenpox virus can be spread from person to person through the air, or by contact with
fluid from chickenpox blisters.
It causes a rash, itching, fever, and tiredness.
It can lead to severe skin infection, scars, pneumonia, brain damage, or death.
A person who has had chickenpox can get a painful rash called shingles years later.
About 12,000 people are hospitalized for chickenpox each year in the United States.
About 100 people die each year in the United States as a result of chickenpox.
The Immunization
Varicella vaccine is a live-virus vaccine. It has been used in some parts of the world, such as
Japan, for over 20 years. It was licensed in the United States in 1995.
What are the risks from chienpox vaccine:
Most people who get chickenpox vaccine do not have any problems with it.
Mild Problems
Soreness or swelling where the shot was given (about 1 out of 5 children and up to 1 out of 3
adolescents and adults)
Fever (1 person out of 10, or less)
Mild rash, up to a month after vaccination (1 person out of 20, or less). It is possible for these
people to infect other members of their household, but this
is extremely rare.
Moderate Problems
Seizure (jerking or staring) caused by fever (less than 1 person out of 1,000).
Severe Problems
Pneumonia (very rare)
Influenza:
The Disease
Almost every child gets the flu (influenza) from time to time. The flu is caused by a virus and
usually occurs from October through May. The rates of infection are highest among children, and
flu symptoms can last a week or longer. For most people, the flu can cause fever, cough, sore
throat, headache, chills, muscle aches, and fatigue. Some people (especially those who have
other illnesses) can get much sicker, and can develop symptoms such as high fever or
pneumonia. On average, about 36,000 people die each year from influenza.
What is influenza?
The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe
illness, and at times can lead to death. Every year in the United
States, on average:
5% to 20% of the population gets the flu;
more than 200,000 people are hospitalized from flu-related complications; and
about 36,000 people die from flu-related causes.
Some people, such as olderserious flu complications.
The Immunization
There are two types of seasonal influenza vaccine: inactivated (killed) vaccine which is given by
an injection (shot), and live attenuated (weakened) vaccine that is sprayed into the nostrils. The
2010-2011 flu vaccine includes H1N1 as one of the three strains it protects against.
Because influenza viruses are always changing, scientists work every year to match the viruses
in the vaccine to those most likely to cause flu that year. For this reason, it is recommended that
influenza vaccines be received every year. It is recommended that everyone older than 6 months
receive flu vaccine. Children younger than 9 years old who have never received a flu shot need to
receive 2 doses of vaccine at least 1 month apart. The live attenuated vaccine that is given as a
nasal spray should not be given to children under 2 years of age, children with asthma, children
on long-term aspirin treatment, or children younger than 5 who have experienced wheezing in the
pat year.
What are the risks for influenza vaccines:
Inactivated Influenza Vaccine:
Mild problems:
soreness, redness, or swelling where the shot was given
fever
aches
If these problems occur, they usually begin soon after the shot and last 1-2 days.
Severe problems:
Life-threatening allergic reactions are very rare. If they do occur, it is within a few minutes to a
few hours after the shot.
Thimerosal:
The primary argument made for an association between thimerosal and ASD is that
the rate of diagnosis of ASD has been steadily increasing since the early 1990s. At
that time also the routine vaccine schedule was increasing, resulting in an increasing
total dose of thimerosal. The antivaccinationists then assume causation from
correlation to blame rising ASD rates on thimerosal.
However, by 2002 thimerosal was completely removed from the routine vaccine
schedule, and now remains only in some flu vaccines. The total dose of thimerosal
exposure is far below 1990 levels, before ASD diagnoses began to rise.
Antivaccinationists predicted that ASD rates would fall dramatically in the years
following the removal of thimerosal from most vaccines – but rates have continued
to rise without even the slightest change in the rate of increase. This is a powerful
refutation of the thimerosal-autism hypothesis, and has been replicated in other
countries.
Further, the best epidemiological evidence suggests that the rise in the diagnosis
rate of ASD is an artifact of broadening the definition of autism, diagnostic
substitution, and increased surveillance. Therefore there isn’t really an autism
“epidemic” just a change in the definition and efforts to make the diagnosis.
How Vaccines Cause Immunity
When making vaccines they use the microbes, or microbe parts, to cause the immune system to
mount the desired immunity. The parts of the vaccine that cause the immune response are called
antigens. Antigens are simply any substances "foreign" to the body (not produced by the body).
Antigens that replicate (live entities that can make more of themselves using the invaded host body)
pose a particular, repeatable threat. These antigens include microbes (like bacteria & viruses) and
other parasites. The immune response causes antibodies to be made by the body after other white
blood cells find the antigens.
This immune response to vaccination is exactly the same as the immune response to any other type
of exposure to antigens that the body encounters every day. Therefore, the immune system or
immune response is not weakened in any way.
Vaccinations can be introduced orally (by mouth) or by injections (by needles) depending on the
type of vaccine. Vaccinations can be weakened or inactivated/dead forms of the microbe that would
cause diseases, or they can be just parts of the microbes that will still result in the same immune
response to the active or live form of the microbe.
Once the antigen is introduced, then your body will detect it with a type of white blood cells called B
lymphocytes. The cells will replicate in response to the detection (clone an army of B lymphocytes).
The newly formed B lymphocytes will then become either plasma cells or memory B cells.
Plasma cells will produce the antibodies to bind to the antigens. It takes 14 days for the antibodies to
reach a maximum concentration in the blood.
Memory B cells will live on (remain dormant in the body) after the antigens are removed and will
cause a quick response once the antigen is encountered again. Memory B cells are the primary reason
for vaccination. They are antigen specific and will prevent infection when that antigen is encountered
again.
The reason why immunization saves lives is because the body is able to build up Memory B cells
before being harmed by an actual live/strong replicating microbe during the first part of the immune
response (before there are any memory B cells). An army is made and standing in wait for any
invading disease causing microbes, including bacteria and viruses. The army can knock it down
before it can make a person sick.
Without this army, an invading microbe will have a chance to make millions of itself by using the cells
and body's resources. A virus will turn a body's cells into virus factory, and infected persons will
spread them to others. The body’s cells that are "eaten" by bacteria or used by viruses will no longer
be free to do their jobs within the body. This cellular destruction by microbes, and the resulting
immune response are what are seen on the outside as an illness. Vaccination prevents illness and the
spread of diseases.