University of Pittsburgh had begun immunization experiments in monkeys using dead polio virus. Soon, however, Salk began to test inoculations in paralyzed polio patients and by 1953 human trials among the general population were initiated. By the spring of the following year, the largest controlled field trials in medical history were underway, and by 1955 the vaccine developed by Salk and his researchers was declared effective. By 1962, Salk's vaccine had reduced the incidence of polio in the United States by 95 percent. The breakthroughs in immunology and vaccine development at Pitt by Salk and his team are considered one of the most
Salk "salk" is meant to operate on a battlefield along with other "salk's" on a landscale not greater than 50 x 100 metres. There are no logistical support elements in the structure of a "jagu". In the Canadian Army 'fireteam' refers to two soldiers paired for fire and movement. Two fireteams form an 'assault group' and two assault groups form a section of eight soldiers. Many other armed forces see the squad as the smallest military unit; some countries' armies have a pair consisting of two soldiers as the smallest military unit. In others a fireteam is composed of two pairs