The graph shows the changing number of cases of whooping cough in Britain from 1940 to 1990, and how the introduction and use of a vaccine for the disease affected the pattern. Apparently, there was a direct link between the administration of the vaccine and the number of cases of whooping cough among children during this period in history.
Overall, the number of cases fell from a high of 170, 000 to almost zero. However, there were significant fluctuations in the trend. For example, just after 1940, there was a surge in the number of cases from 50, 000 to approximately 170, 000. Although the figure fell back in the next few years, it peaked again in the early 1950s and fluctuated considerably until the introduction of a vaccination in the late 1950s.
Following this, the number of cases dropped sharply to well below 20, 000 in the mid-1970s, until a sudden fall in vaccinations, from 81 percent to 30 percent, resulted in a parallel rise in the incidence of the illness. Figures then went up again to 60, 000 around 1980, but gradually fell back to their earlier level as vaccinations were resumed. By 1990, 94 percent of children were being vaccinated against whooping cough, and there were few, if any, cases.
The graph
shows
the changing
number
of cases of whooping cough in Britain from 1940 to 1990, and how the introduction and
use
of a vaccine for the disease
affected
the pattern.
Apparently
, there was a direct link between the administration of the vaccine and the
number
of cases of whooping cough among children during this period in history.
Overall
, the
number
of cases fell from a high of 170, 000 to almost zero.
However
, there were significant fluctuations in the trend.
For example
,
just
after 1940, there was a surge in the
number
of cases from 50, 000 to approximately 170, 000. Although the figure fell back in the
next
few years, it peaked again in the early 1950s and fluctuated
considerably
until the introduction of a vaccination in the late 1950s.
Following this, the
number
of cases dropped
sharply
to well below 20, 000 in the mid-1970s, until a sudden fall in vaccinations, from 81 percent to 30 percent, resulted in a parallel rise in the incidence of the illness. Figures then went up again to 60, 000 around 1980,
but
gradually
fell back to their earlier level as vaccinations
were resumed
. By 1990, 94 percent of children were
being vaccinated
against whooping cough, and there were few, if any, cases.