Patients found to have measles despite being immunised

Matt Woodley

26/06/2019 3:27:06 PM

Research has found 13 people in Victoria contracted measles in 2014–17 even though they had received at least one dose of vaccine.

Katherine Gibney
Dr Katherine Gibney says the main message from the finding is that one measles vaccine is not enough. (Image: Peter Casamento)

The research, led by University of Melbourne epidemiologist Dr Katherine Gibney, has raised doubts about the long-term efficacy of measles vaccines.
The 13 cases were confirmed as ‘secondary vaccine failure’, with antibodies found in the patients’ blood, but protection had waned in the lead up to contracting measles.
Dr Gibney told newsGP the findings are of particular relevance to GPs, as they are often the first point of contact for people suspected of having measles and secondary vaccine failures generally present with different symptoms.
‘These cases weren’t really typical … they were a bit less likely to have the fever, the cough and the coryza. Although they did have a rash, there were notes indicating that it wasn’t very much, or didn’t last very long or was atypical,’ she said.
‘Our message to doctors is that if you suspect measles, don’t just rely on the serology, which detects antibodies to measles, but also perform a PCR [polymerase chain reaction] test, which detects the actual virus.’
At least one of the secondary immune failure cases was found to have transferred the disease to two infants who were too young for vaccination.
Australia has already recorded 128 measles cases this year, the highest since 2014, and Dr Gibney said the main message is that one vaccine is not enough.
‘Until 1992 we were only giving one vaccine, so there are lots of adults out there who … haven’t had enough measles vaccine,’ she said.
‘Anyone who is unsure if they have had two doses of measles vaccine should see their doctor about getting an additional dose.’
While one of the 13 cases contracted measles after having previously received two vaccines, Dr Gibney said those who have only had one vaccine are at greater risk – especially if they aren’t getting a natural immunity boost from the disease circulating in the community.
‘If you had been vaccinated and came into contact with someone with measles you might get a little natural boost in your antibody levels,’ she explained.
‘Overall, in countries that have eliminated measles transmission, this is likely to emerge as a problem. There isn’t going to be an enormous number of cases, but it will be important in terms of recognising measles, because the cases are a bit different to those who aren’t immune.
‘More work needs to be done in the area of a third vaccine before we can routinely recommend this – we need to know definitively if a third booster shot will extend the immunity to measles for a lifetime.’

measles vaccination vaccine

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