Polio is a disease that has caused paralysis in millions of children worldwide over the years. Polio is caused by a virus that lives in the throat and intestinal tract. It is spread mainly through contact with the feces of an infected person (for instance, by changing diapers).

Some children who get polio don’t feel ill at all. Others have the symptoms of a common cold, sometimes accompanied by pain and stiffness in the neck, back and legs. But some

children get severe muscle pain, and within a week can be paralyzed — in other words, loose the use of their muscles. Usually paralysis affects a child’s legs, but it can also affect other muscles, including those that control breathing.

Depending on the sites of paralysis, polio can be classified as spinal, bulbar, or spino-bulbar disease. Progression to maximum paralysis is rapid (2–4 days), is usuallyassociated with fever and muscle pain, and rarely continues after the patient’s temperaturehas returned to normal.

Spinal paralysis is typically asymmetric and moresevere proximally than distally. Deep tendon reflexes are absent or diminished. Bulbarparalysis can compromise respiration and swallowing.

Paralytic polio is fatal in 2%–10% of cases. After the acute episode, many patients recover at least some musclefunction and prognosis for recovery can usually be established within 6 months afteronset of paralytic manifestations.

There is no treatment for polio, and some children die from it. The incubation period for poliomyelitis is commonly 6 to 20 days with a range of 3 to 35 days.

DESCRIPTION

Two different kinds of Polio vaccine are available:

• A live attenuated (weakened) oral polio vaccine (OPV).  OPV is given orally.
• An inactivated (killed) polio vaccine (IPV). Unlike OPV, IPV has to be injected by a trained health worker.

Both vaccines are highly effective against all three types of poliovirus. There are, however, significant differences in the way each vaccine works.

Both vaccines are highly effective against all three types of poliovirus. There are, however, significant differences in the way each vaccine works.
•  ORAL POLIO VACCINE (OPV)
The action of oral polio vaccine (OPV) is two-pronged: OPV produces antibodies in the blood (‘humoral’ or serum immunity) to all three types of poliovirus. In the event of infection, this will protect the individual against polio paralysis by preventing the spread of poliovirus to the nervous system. OPV also produces a local immune response in the lining (‘mucous membrane’) of the intestines – the primary site for poliovirus multiplication. The antibodies limit the multiplication of ‘wild’ (naturally occurring) virus inside the gut, preventing effective infection. This intestinal immune response to OPV is probably the main reason why mass campaigns with OPV can rapidly stop person-to-person transmission of wild poliovirus.
Advantages of Oral Polio Vaccine

OPV is an orally applicable vaccine. It does not have to be administered by a trained health worker, can be given by volunteers, and – unlike most other vaccines – does not require sterile injection equipment.

The short-term shedding of vaccine virus in the stools of recently immunized children means that in areas where hygiene and sanitation are poor – and the incidence of polio is likely to be highest – immunization with OPV can result in the ‘passive’ immunization of persons within close contact. As discussed above, the unique ability of OPV to induce intestinal, local immunity is probably responsible for the extraordinary effect of OPV mass campaigns in interrupting wild poliovirus transmission ( Pulse Polio ). Due to these advantages, OPV remains the vaccine of choice for the eradication of polio, which would not be feasible with inactivated polio vaccine (IPV).

                                                               Disadvantages of Oral Polio Vaccine
Although OPV is safe and effective, in extremely rare cases (approx. 1 in every 2.5 million doses of the vaccine) the live attenuated vaccine virus in OPV can cause paralysis – either in the vaccinated child, or in a close contact. Immune deficiency of the recipient may be among the causes. This extremely low risk of Vaccine Associated Paralytic Poliomyelitis (VAPP) is well known to, and accepted by most public health programmes in the world because without OPV, hundreds of thousands of children would be crippled every year. Immunization programmes in countries where the risk of wild-virus caused polio has come down to zero are now considering combined immunization schedules using both OPV and IPV.
Rarely, a strain of poliovirus in OPV may genetically change and circulate among a population. These are known as vaccine-derived polioviruses (VDPV) and knowledge on them is growing.

•  INACTIVATED POLIO VACCINE (IPV)
Inactivated polio vaccine (IPV) needs to be injected and works by producing protective antibodies in the blood (serum immunity) thus preventing the spread of poliovirus to the central nervous system. However, it induces only very low levels of immunity to polivirus locally, inside the gut. As a result, it provides individual protection against polio paralysis but, unlike OPV, cannot prevent the spread of wild polio virus.
Advantages of inactivated Polio Vaccine
IPV is not a ‘live’ vaccine – the polio virus is inactivated – and immunization with IPV carries no risk of vaccine-associated polio paralysis. Immunization with IPV triggers an excellent response of the immune system in most IPV recipients.
Disadvantages of inactivated Polio Vaccine
Unlike the oral vaccine, IPV confers only very little immunity in the intestinal tract. When a person immunized with IPV is infected with wild poliovirus, virus can still multiply inside the intestines and be shed in stools,  risking continued circulation. For this reason, OPV is the vaccine of choice wherever a polio outbreak needs to be contained, even in countries which rely exclusively on IPV for their routine immunization programme. Other disadvantages of IPV include the price, the cost of the syringe, and the need for trained health workers to administer the vaccine using sterile injection procedures.

SCHEDULE

1.      We should continue to use OPV till we achieve polio eradication in India. IPV can be used additionally for individual protection.

2.      OPV must be given to children less than 5 years of age at the time of each supplementary immunisation activity.

ADVERSE EVENTS

What should I look for?

Look for any unusual condition, such as a serious allergic reaction, high fever, unusual behavior, or signs of paralysis. If a serious allergic reaction occurred, it would happen within a few  minutes to a few hours after the shot. Signs of a serious allergic reaction can include difficulty breathing, weakness, hoarseness or wheezing, a fast heart beat, hives, dizziness,

paleness, or swelling of the throat. If paralysis were to occur, it could happen from about a week to about a month after the vaccination. Symptoms might include:

•  severe muscle aches and spasms
•  weakness
•  loss of movement in an arm or leg

What should I do?

·         Call a doctor, or get the person to a doctor right away.

·         Tell your doctor what happened, the date and time it happened, and when the vaccination was given.

·         Ask your doctor, nurse, or health department to report the adverse event to [email protected] , [email protected]

·         Reporting reactions helps experts learn about possible problems with vaccines.

CONTRAINDICATIONS AND PRECAUTIONS

These people should not get OPV:

• ·         Anyone who is taking long-term steroids or any other drug that affects the immune system.
• ·         Anyone who has cancer or is getting chemotherapy.
• ·         Anyone who has AIDS or HIV infection, or another disease that affects the immune system.
• ·         If anyone in these three groups will be changing a child’s diapers or be in close contact with a child getting polio
  vaccine, that child should not get OPV.
• ·         A baby should not get OPV if someone who will be in close contact with the baby (for instance changing diapers) has
  never had any kind of polio vaccine.
• ·         Anyone who has had a severe allergic reaction to a dose of OPV should not get another dose.

These people should wait:

Anyone who is moderately or severely ill at the time the immunization is scheduled should usually wait until they recover before getting OPV. People with minor illnesses, such as a cold, may be vaccinated. Ask your health care provider for more information.

IPV: Immunization with Inactivated Poliomyelitis Vaccine should be deferred in the presence of any acute illness, including febrile illness, to avoid superimposing adverse effects from the vaccine on the underlying illness or mistakenly identifying a manifestation of the underlying illness as a complication of vaccine use. A minor illness such as mild upper respiratory infection is not reason to defer immunization.

Allergy to any component of Inactivated Poliomyelitis Vaccine, or its container, or an anaphylactic or other allergic reaction to a previous dose of IPV is a contraindication to vaccination.

STORAGE

OPV: The vaccine must be stored at -20⁰C or below under frozen state for storage up to 2 years. When the vaccine is thawed ( liquid form), it must be kept in refrigerator at 2⁰C to 8⁰C. Vaccine if stored at 2⁰C to 8⁰C shall remain good for only 4-6 months.

IPV: Store at 2° to 8° C.  DO NOT FREEZE. Discard product if exposed to freezing.
Do not use after expiration date.

PRESENTATION

OPV: A single dose of oral polio vaccine (usually two drops) contains

• ·         Live attenuated Sabin strain Polio viruses Type 1 – 1,000,000 infectious units
• ·         Live attenuated Sabin strain Polio viruses Type 2 – 100,000 infectious units
• ·         Live attenuated Sabin strain Polio viruses Type 3 – 600,000 infectious units
• ·         MgCl2 ( Stabilizer ) – 1M
• ·         Phenol red ( Indicator )
• ·         Kanamycin sulphate 9 (Preservative ) – 20 mcg

Squeezable Plastic tube / vial with VVM ( Vaccine Vial Monitor) Label (20 dose).
IPV: One dose of 0.5ml contains

• · Polio virus type 1 ( inactivated ) (Mahoney)  40DU
• · Polio virus type 2 ( inactivated ) (MEF1)       8DU
• · Polio virus type 3 ( inactivated ) (Saukett)     32D
•   Nonmedicinal Ingredients are 2-phenoxyethanol, formaldehyde, residual calf serum protein, neomycin, streptomycin and polymyxin B, Medium 199 Hanks (without phenol red).