Why are children given polio drops regularly on certain days in a year?
Every child receives a dose of Oral Polio Vaccine (OPV), a live, attenuated virus which colonises the gastrointestinal tract. This virus competitively inhibits the wild, disease-causing poliovirus. Not only does this prevent pernicious infection in the host, it precludes transmission of the wild poliovirus to other hosts. Since poliovirus cannot survive outside a host for more than two weeks, theoretically it would be eradicated, resulting in the eradication of poliomyelitis. Herd Immunity comes into play, in this type of programme given on certain days, which may help in the eradication of the disease. When many hosts are vaccinated, especially simultaneously, the transmission of wild virus is blocked, and the virus is unable to find another susceptible individual to infect. Because poliovirus can only survive for a short time in the environment (a few weeks at room temperature, and a few months between 0–8° Celsius (32–46° Fahrenheit)) without a human host the virus dies out. So, you
