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Breakthrough measles (reinfection)
The term 'breakthrough measles' (previously referred to as 'reinfection') is used to describe a confirmed case of measles in someone who developed immunity to measles, either from natural measles or from prior receipt of measles containing vaccine.
The immunological characteristics of breakthrough measles differ from those of primary vaccine failure, which is thought to occur when patients never develop immunity, for example when measles vaccine is given in the presence of maternal antibody
Breakthrough measles cases are usually seen in patients who have received 2 doses of measles-containing vaccine, and antibody testing may be misinterpreted
In measles endemic areas breakthrough cases represent fewer than 10% of total infections, but this will increase as vaccination coverage in the general population rises (2)
In a highly vaccinated population and with the increasing availability of PCR testing it is inevitable that more breakthrough measles infections will be identified