POLIO VACCINE – INTRODUCTION
Polio vaccine provides protection against Poliomyelitis (also referred to as Polio)
Polio is an infectious disease caused by polio virus. The World Health Organization (WHO) has targeted the elimination of polio by the year 2003.
Clinical Symptoms: It enters a child’s (or adult’s) body through the mouth. Not everyone who’s infected with polio gets sick, and many (approximately 99%) who do get sick have only mild symptoms:
- cough, fever and stomach pain
- a stiff neck and headache
In <1% children the Poliovirus attacks the nervous system and can cause permanent muscle paralysis (can’t move leg or arm) or weakness. When the virus affects the muscles of the chest, it can even kill because of the paralysis of the muscles used in respiration.
Children infected with the virus excrete it in their stools, thereby posing a danger for the unimmunized children around them.
Poliovirus: Three different strains of poliovirus can cause polio (Type 1, 2, or 3). Poliovirus infection provides lifelong immunity against the disease, but this protection is limited to the particular type of poliovirus involved (Type 1, 2, or 3). Unfortunately, infection with one type does not protect an individual against infection with the other two types.
Risk of transmission: The infected child is more infectious just prior to and within first 2 weeks after the onset of paralysis.
Prevention of transmission: The polio virus is excreted in stool of the infected child for about six weeks. To reduce the risk of passing on the virus particles, people in contact with the ill child need to observe strict personal hygiene. So, wash hands before preparing food, eating or drinking, as well as after changing nappies, toilet etc.
Prevention of Polio
The development of effective vaccines to prevent paralytic polio was one of the major medical breakthroughs of the 20th century.
Two different kinds of vaccine are available.
Both vaccines are highly effective against all 3 types of poliovirus. However, there are significant differences in the way each vaccine works. Both vaccines provide immunity to polio, but Oral Polio Vaccine is especially effective in controlling the epidemics (attenuated virus excreted in stool and may spread to other persons and therefore, non-immunized person may also get immunized).