Mumps cases soar amid fears MMR jab can ‘wear of f ’
MUMPS cases soared in Scotland last year amid fears the MMR vaccine does not give long-lasting protection.
There were 784 instances of the viral infection in 2019 – rising to 853 in the first three months of last year.
The Covid lockdown then halted the spread.
The growing number of cases may be down to several factors, warns a report by health Protection Scotland (hPS).
These include the vaccine not producing enough immunity in some people, or its protection ‘waning’ over time.
Children are given an MMR (measles, mumps and rubella) jab but the mumps component, unlike the other two, does not offer lifelong immunity.
Cases of mumps have been variable in recent years, including outbreaks linked to universities where young people live in close proximity – at the same age as MMR immunity starts to wane. Those affected by mumps in Scotland are usually between the ages of 17 and 34.
The disease is most recognisable by lumps on the side of the face.
Other symptoms include headache, joint pain and a high temperature. Most cases are mild but complications can include meningitis and inflammation of the pancreas.
The hPS report states: ‘The observed increase in cases may represent poor initial immune response to the mumps component of the MMR, waning immunity, or a combination of both.’
Regarding last year, the report added: ‘This trend has since shown a significant decline, with only ten cases reported between April and June, and a single case reported in December.
‘This is most likely to be the result of social distancing measures implemented to mitigate the transmission of Covid-19, which will also have interrupted the transmission of mumps, as well as reducing attendance at primary care to diagnose.’
All children in Scotland are offered the MMR jab when they reach a year old, with a booster before they begin school.
A total of 96.7 per cent of Scots five-year-olds receive a first dose and 92.8 per cent get a second, according to the latest figures, for last December.
There were 281 laboratory confirmed mumps cases in 2018, down from 385 the year before. Cases last year were mostly in teenagers and young adults.
A study of mumps outbreaks in the US between 2010 and 2015 found that 78 per cent were at universities.
Universities and colleges are perfect breeding grounds for viruses because young people from different areas live in shared accommodation and congregate in large numbers.
Some students, such as those from countries without high uptake rates, may not have had a mumps vaccine or a booster.
Another study found those affected in mumps outbreaks had been vaccinated around 14 years earlier. It is thought that waning immunity after that time leads to periodic outbreaks.
Some experts say a third MMR jab should be given to people during localised outbreaks.
But introducing a third booster to the population in general could mean outbreaks among older adults when that immunity wears off.
PhS said: ‘We produce periodic updates of our surveillance data and will be updating our web content to describe the patterns observed.’
Dr Mary Ramsay of Public health England, which supports the UK’s Joint Committee on Vaccination and Immunisation, said: ‘Those that have received two doses of the MMR vaccine and do get mumps have a much milder form. Children and young adults who have not had the full course can get the doses missed from their GP.’
‘Waning immunity’