The Oral Polio Vaccine (OPV) is a vaccine used to protect against poliomyelitis, a highly infectious viral disease that can lead to paralysis. OPV contains weakened forms of the poliovirus, which stimulate the immune system to produce antibodies without causing the disease. It is administered orally, making it easy to distribute, especially in areas with limited healthcare access. OPV has played a crucial role in global efforts to eradicate polio, significantly reducing the number of cases worldwide. The vaccine is part of the routine immunization schedule in many countries and is often used during mass vaccination campaigns, particularly in regions where polio is still a threat.