Friday, October 28, 2011

Second dose of measles, mumps and rubella vaccine is must to boost immunity

By Syed Akbar
Hyderabad: Vaccination for measles, mumps and rubella (MMR)
should be followed up by a second dose to provide strong immunity to
children against these troublesome diseases. A single dose of MMR
vaccine does not provide the required immunity leaving the vaccinated
child vulnerable.

According to a research study by senior researchers Dr G Sunil, Dr
Shukla Das, Dr VG Ramachandran and Dr SK Arora, children who receive
single dose MMR vaccine get only 20.4 per cent protection against
measles, 87.4 per cent against mumps and 75.7 per cent against
rubella. These children, when given the second dose of MMR vaccine,
showed increased immunity. The protection percentage went up to 72.6
for measles and 100 per cent for mumps and rubella.

MMR vaccine is not covered under the universal immunisation programme
in the country. But many parents immunise their children against these
diseases with a single dose vaccine between 15 and 18 months. The
research study revealed that a booster dose would give sure protection
to children.

"The percentage of children protected against measles was found to be
alarmingly low. Though the observed protection against mumps and
rubella was adequate, its durability was not known. The need for
re-appraisal of the current MMR immunisation policy is called for by
carrying out longitudinal studies on a larger sample," they pointed
out in the Indian Council of Medical Research journal.

According to the team, infants who receive measles vaccine before 12
months of age should be given two additional doses of measles antigen
containing vaccine at 12-15 months and 4-6 year of age. As far as
protection against mumps is concerned, accumulated global experience
has shown that two doses of mumps antigen containing vaccine are
required for a long-lasting protection.

The vaccine for rubella is considered as highly efficacious and the
immunity following a single dose is assumed to be life long, although
rubella antibodies may fall below detectable levels with time.

"Over a period of time the pool of susceptible children accumulates,
including the children who missed the opportunity of being vaccinated
with the first dose, serving as a fertile ground for an epidemic to
take place," they warned.

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