Thank you for consulting with us at Doctor spring. I understand that you are worried about the fact that your daughter has received an extra dose of OPV accidentally.

Polio virus is basically of three serotypes (three different types, each of which can cause the same disease). It causes disease by invading the nerves of the body and causes paralysis (weakness of muscles in the body) in rare cases may even cause death due to invasion of the muscles necessary for respiration and swallowing.

Polio is transmitted via ingestion of infected food and water similar to cholera and typhoid. When a person is infected with polio virus, the virus multiplies in number in the intestine and is excreted in the feces form where it can spread from person to person. Polio mainly affects children under 5 years of age and rarely adults of they have a lot level of immunity against the virus.

After the primary attack of polio, when the child has generalized paralysis of all muscle in the body and fever, there is a gradual recovery during which the child regains power in most of the muscles. Residual paralysis mainly of the legs may be present in up to one in 200 people affected by polio.

Polio is a vaccine preventable disease. There are two types of vaccines available against polio: Oral polio vaccine and Injectable polio vaccine. In countries where polio is still endemic are there is a chance of re-emergence, OPV is the vaccine of choice due to various reasons. The OPV contains all three serotypes od the virus in particular quantities.

When the OPV is administered, the vaccine virus also infects the intestine but it does not cause disease. It is excreted in the feces and can infect other children who have not been immunized and can protect them too. Typically, it is said that 4 doses of 2 drops of polio vaccine are sufficient to protect a child. But the WHO recommends that in tropical countries like India where there is a high rate of infection of the intestines with other viruses, even fully immunized children should be administered additional doses on all National immunization days and in India on Pulse Polio days.

Additional doses of polio vaccine do not cause any adverse effects and in fact can offer additional protection to your child. Very rarely, OPV can cause paralysis in 1 in 2.5 million individuals which has occurred only with the first two doses of the vaccine and rarely with additional doses.

So, don't panic, you child is very safe. Hope this information was of use to you.