11.   No vaccine exists for hepatitis C.

12.   No vaccine exists for the virus, and treatment is limited to the symptoms of the illness.

13.   No vaccine exists.

14.   One reason is that not enough vaccine exists.

15.   The magazine contends that safer vaccines exist, but they are more expensive and are not promoted strongly enough by drug companies, doctors and federal regulators.

16.   Vaccine exists.

17.   Vaccines do not exist for all strains.

18.   Vaccines exist for two other hepatitis viruses.

19.   While a vaccine does not exist, the use of a periodic medication can prevent the development of microfilaria, thereby preventing the development of an adult worm.

20.   Yet effective vaccines do not exist, in part because most of the victims live in poverty and cannot afford drugs.

n. + exist >>共 1655
problem 4.39%
evidence 2.06%
possibility 1.59%
opportunity 1.28%
difference 1.17%
life 1.15%
condition 1.10%
technology 1.04%
system 0.84%
group 0.78%
vaccine 0.44%
vaccine + v. >>共 159
be 41.06%
work 4.50%
cause 3.91%
protect 3.32%
have 2.93%
exist 2.64%
prevent 2.15%
use 2.15%
make 1.66%
contain 1.27%
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