3.3.2 Storage, dosage and schedule of measles vaccine
The vials containing the dry measles vaccine powder can be frozen for long-term storage, but after reconstitution with the correct diluent, measles vaccine should be kept at between +2°C and +8°C, and never frozen. Any remaining reconstituted vaccine must be thrown away after six hours, or at the end of the immunization session, whichever comes first.
One dose of 0.5 ml of measles vaccine is injected subcutaneously (into the fatty layer below the skin and above the muscle) in the outer upper arm as soon as possible after nine months of age. Waiting this long is advisable because the maternal antibodies against measles that are transferred to the unborn baby before birth last longer in the blood of the baby than other antibodies. As a result, immunization with measles vaccine is often not effective before nine months of age. The aim in the EPI in Ethiopia is to give measles vaccine to all children at nine months of age. To achieve high-level population immunity, a second dose is ideally given after 12 months of age during supplementary immunization activities.
What are antibodies and how can maternal antibodies help in combating measles?
You learnt about antibodies in Study Session 1.
Antibodies are specialized proteins that circulate in the blood and other body fluids. They are produced by B cells in the immune system. They identify foreign antigens, such as those found on infectious agents (e.g. the measles virus), and neutralise them so they are unable to cause disease. Maternal antibodies are those produced by the mother when she is vaccinated, which are transmitted passively to the fetus across the placenta, or to her baby in her breastmilk. Maternal antibodies directed against measles viruses will protect the infant from measles in the first few months of his or her life.
In special situations, for instance in measles outbreaks, in emergencies such as in refugee camps with high measles transmission, or among HIV-infected children, an ‘early’ extra dose of measles vaccine may be given at six months. If a child has received measles vaccine before nine months of age, a second dose should be administered at nine months, or as soon as possible afterwards. All children should ideally receive a supplementary dose of measles vaccine after 12 months of age as part of measles elimination campaigns.
3.3 Measles vaccine