In an air-handling system that provides cooled air to occupants of a building, most of the air is returned from the space back to the air handler to be reused. This is called â¦ Return Air, or RA. However, some fresh air (called Outside Air, or OA) must be mixed in.
Polio is a viral infection that can cause permanent paralysis. The inactivated poliovirus vaccine (IPV) is usually given at ages 2 months, 4 months, 6â18 months, and 4â6 years. Though the oral poliovirus vaccine (OPV) is still used in many parts of the world, it has not been used in the United States since 2000.
Poliomyelitis (Polio) in Children. Poliomyelitis, also called polio, is a highly contagious infectious disease caused by three types of poliovirus. The poliovirus is a virus most recognized for its destruction to the nervous system causing paralysis.wo versions of the vaccine may be administered: IPV. Inactivated polio vaccine (IPV) is administered by injection (a shot). This vaccine is administered at all four immunization visits. Administration of the IPV cannot cause polio and is safe to use for individuals with weakened immune systems.