Measles, mumps and rubella are contagious infections caused by viruses
and all three are present in Sri Lanka. These diseases are highly infectious and
can cause severe complications. Measles is one of the leading causes of
childhood morbidity and mortality in developing countries and still remains a
major public health concern in developed countries. It can cause severe
complications such as otitis media, pneumonia and encephalitis 1. Meningoencephalitis
in children and epididymo-orchitis in adolescent boys are the most common
complications of mumps 2. Rubella is an exanthematous illness with high
incidence among adults. Congenital rubella syndrome is a result of rubella
infection in early pregnancy. All these three infections can be prevented by
Primary protection against these three infectious is provided mainly by
maternally transferred antibodies. The maternal transfer of antibodies depends
on few factors such as antibody levels of the mother, gestational age and
efficiency of transfer of maternal antibody.
The prevalence of maternal antibody in infants at any given time
therefore depends on aforementioned factors and the rate of decay of maternal
antibody in infant after birth 3. Active placental transfer of IgG is the important
component of the neonatal immunological defense mechanisms against infection.
This begins during the third trimester of pregnancy and increases sharply
thereafter. At the end of gestation,
IgG concentrations in fetal serum generally exceed their maternal levels 4. In addition to that, it has been shown that
passively transferred maternal antibodies present in breast milk and colostrum
renders protection to the young infants against respiratory infections and extraintestinal
infections, such as otitis media 5. It will be interesting to know whether this
is valid for the 3 viral infections studied here.
Mothers who have had natural infections have high levels of antibodies
compared to vaccinated mothers and they transfer higher levels of antibodies to
their infants 3. Studies have shown that HIV- type 1 infection and placental
malaria negatively affect placental transfer 6. Therefore results in
transferring low amount of antibodies to infants. Passively transferred IgG is
subjected to an exponential clearance rate with a half-life of 35–60 days 3.
Studies have shown that the maternal antibodies wane off rapidly in the first 6
months and mostly absent by the end of first year of life. Therefore it is necessary to vaccinate the
infants against these infections. Vaccines are available against each of above
infections individually as well as combinations like MMR vaccine.
Biological differences associated with the gender of an individual have
been reported to be a major source of variation affecting immune responses to
vaccination or infection 7.
Gender-specific differences in humoral responses following vaccination have
been found for a large number of viral and bacterial vaccines including rubella
and measles 8. Differences in the rate of decay of the antibody levels
against individual components of the measles–mumps–rubella (MMR) vaccine were also
reported between the genders. It has been shown that the percentage of MMR
recipients who developed a protective range of mumps IgG after one dose and two
doses of the vaccine was more among females than males but IgG against measles
was more among males than females and equal for rubella IgG 9.
Furthermore there were no previous studies reporting the
maternal antibody difference between genders before MMR vaccination. The aim of
the current study was to determine the level of maternally transferred
antibodies against measles, mumps and rubella at birth and in infants between
6- 12 months of age and compare them between the genders.