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.
The polio shot (IPV) does not cause polio The recommended schedule for polio vaccination is three doses of IPV at 2, 4, and 6 months of age, and a booster at 4-6 years of age. Booster doses of polio vaccine are also recommended for persons traveling to areas of the world where polio is still a problem.olio [PO-lee-oh] is a viral disease that can damage the nervous system and cause paralysis. The polio virus enters the body through the mouth, usually from hands contaminated with the stool of an infected person. Polio is preventable by immunization.