POLIO BEFORE AND AFTER THE VACCINE
3. What trend does the graph show? What explains the trend?
between the year 1950 to 1963
Based on the given information, it is difficult to provide a specific answer without the actual graph. However, if we assume that the graph shows a decrease in polio cases from 1950 to 1963, then the trend would indicate a decline in polio incidence.
The explanation for this trend could be the introduction and widespread vaccination of the polio vaccine during this time period. The polio vaccine, developed by Jonas Salk in 1955 and later the oral polio vaccine developed by Albert Sabin in the early 1960s, played a significant role in reducing the number of polio cases.
These vaccines helped to create immunity against the poliovirus, preventing individuals from contracting the disease and therefore reducing the spread of polio within communities. The success of the polio vaccine programs led to a significant decline in polio cases, eventually leading to the elimination or near eradication of polio in many parts of the world.