The Americas
Unfortunately, there are still
countries in the world, where poliomyelitis is endemic. This means that the
disease could flare up at any time or in any place. Thus, polio vaccine and
immunization schedules are important to pediatric medical professionals, as
well as parents and others, who desire to protect children and prevent the
disease from spreading.
What is poliomyelitis?
"Poliomyelitis, often
called polio or infantile paralysis, is an acute viral infectious disease
spread from person to person, primarily via the fecal-oral route. The term
derives from the Greek polios, meaning "grey", myelos, referring to
the "spinal cord," and the suffix -itis, which denotes
inflammation." (2)
What causes polio?
"Polio is caused by
infection with a member of the genus Enterovirus known as poliovirus (PV). This
group of RNA viruses prefers to inhabit the gastrointestinal tract." (3)
This disease can spread among
children through human contact, as well as contaminated water or food and thus,
hygiene is important. Another effective method of protection and disease
prevention is vaccination.
What is the appropriate
vaccination schedule for children?
Children are normally given
polio vaccine as injections (IPV) or drops (OPV). This is four doses of polio
vaccine, at 2, 4, 6-8 months and between 4-6 years of age. (4)
Parents, guardians and others
may have questions about the nature of this illness, including the following:
What happens to a child (or an
adult) who has been infected by polio?
"In about 1% of the cases
the virus enters the central nervous system, preferentially infecting and
destroying motor neurons leading to muscle weakness and acute flaccid
paralysis. Different types of paralysis may occur, depending upon the nerves
involved. Spinal polio is the most common form, characterized by asymmetric
paralysis that often involves the legs. Bulbar polio leads to weakness of
muscles innervated by cranial nerves. Bulbospinal polio is a combination of
bulbar and spinal paralysis." (5)
Historically, when was polio
first recognized as a disease process threatening the lives of children?
"Although major polio
epidemics were unknown before the late 19th century, polio was one of the most
dreaded childhood diseases of the 20th century. Polio epidemics have crippled
thousands of people, mostly young children; the disease has caused paralysis
and death for much of history." (6)
Who discovered polio?
"Poliomyelitis was first
recognized as a distinct condition, by Jakob Heine, in 1840. Its causative
agent, poliovirus, was identified in 1908, by Karl Landsteiner." (7)
When did polio vaccines begin
to be developed?
"The polio vaccines were
developed by Jonas Salk, in 1952 and Albert Sabin, in 1962." (8)
How are children and others,
protected by polio vaccine?
"Individuals who are
exposed to the virus, either through infection or by immunization with polio
vaccine, develop immunity. In immune individuals, IgA antibodies against
poliovirus are present in the tonsils and gastrointestinal tract and are able
to block virus replication; IgG and IgM antibodies against PV can prevent the
spread of the virus to motor neurons of the central nervous system." (9)
Does polio vaccine protect
children against all possible types of polio?
"Infection or vaccination
with one serotype of poliovirus does not provide immunity against the other
serotypes, and full immunity requires exposure to each serotype." (10)
Globally, how many polio
vaccines are there now?
"Two vaccines are used
throughout the world to combat polio. Both vaccines induce immunity to polio,
efficiently blocking person-to-person transmission of wild poliovirus, thereby
protecting both individual vaccine recipients and the wider community (so
called herd immunity)." (11)
What is Salk vaccine?
"The Salk vaccine, or
inactivated poliovirus vaccine (IPV), is based on poliovirus grown in a type of
monkey kidney tissue culture (Vero cell line), which is chemically inactivated
with formalin." (12)
How does Sabin polio vaccine
differ from Salk vaccine?
"... Albert Sabin
developed an oral polio vaccine (OPV) using live but weakened (attenuated)
virus, produced by the repeated passage of the virus through non-human cells at
sub-physiological temperatures. Human trials of Sabin's vaccine began in 1957
and it was licensed in 1962." (13)
When did polio initially become
a serious, global concern?
"Small localized paralytic
polio epidemics began to appear in Europe and the United States Australia , and New Zealand
How did this epidemic affect
children?
By 1950, the peak age incidence
of paralytic poliomyelitis in the United States had shifted from infants to
children, aged five to nine years, when the risk of paralysis is greater; about
one third of the cases were reported in persons over 15 years of age. (15)
What efforts are currently
underway to eradicate polio in the future?
"Enhanced vaccination
efforts led by the World Health Organization, UNICEF and Rotary International
could result in global eradication of the disease." (16)
Note that there are still serious medical concerns related
to mass vaccination for polio. The American
Academy
1. Children and caregivers, unable to fight infections or on long-term steroid treatment, should not be given POV. Neither should those with cancer or AIDS/HIV.
2. Children allergic to
neomycin, streptomycin or polymyxin B, should not receive IPV.
3. OPV can cause poliomyelitis,
as it is a live vaccine, while IPV is not.
4. Side effects to polio
vaccine may include hives, itching, burning sensation of the skin, difficulty
breathing and other symptoms normally associated with shock. (17)
Note that those who have
further questions with regard to polio vaccine for children or immunization
schedules are encouraged to consult their family physicians or pediatricians.
There is also educational information about polio, as well as polio vaccine for
children and other family members, available on the Internet.
2. Ibid.
3. Ibid.
5. Op. Cit. Polio
6. Ibid.
7. Ibid.
8. Ibid.
9. Ibid.
10. Ibid.
11. Ibid.
12. Ibid.
13. Ibid.
14. Ibid.
15. Ibid.
16. Ibid.
17. Op. Cit. 990101c.html
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