Other serious problems, including severe
brain reactions and low blood count, have been reported after chickenpox
vaccination. These happen so rarely experts cannot tell whether they are
caused by the vaccine or not. If they are, it is extremely rare.
Note: The first dose of
MMRV vaccine has been associated with rash and higher
rates of fever than MMR and varicella vaccines given separately. Rash
has been reported in about 1 person in 20 and fever in about 1 person in
5.
Seizures caused by a fever are also
reported more often after MMRV. These usually occur 5-12 days after the
first dose.