Wild mumps infection carries low risk of serious complications
Regarding the quick quiz on mumps (Clinical, November 17), what is Dr Stollery's source for meningitis incidence of 5 per cent?
Certainly in the 1960s meningoencephalitis occurred in less than 2.5 per cent of clinical cases under the age of 201. As the incidence of subclinical infection is 30-40 per cent, this means it happens in less than 1 per cent of cases and the prognosis is usually good2.
Dr Stollery also seems to have omitted to quiz us on the generally benign nature and longlasting immunity conferred by wild mumps infection3. After 15 years of vaccinating against mumps with MMR, outbreaks have occurred in the north of this country for the last two years for example in Stockport, where 95 per cent are vaccinated and one-third of cases are aged over 15. As one witty doctor commented, perhaps this is the Government's answer to population control.
1. Meyer MB. An epidemiological study of mumps; its spread in schools and families. Am J Hyg; 75:259-281
2. Pattersons Sick Children, 9th Ed 1971 p613
3. Harrison's Principles of Internal Medicine 11th Ed, 1987 p709
Dr Jayne Donegan
Dr Nigel Stollery replies:
The 5 per cent incidence comes from page 61 of Clinical Medicine, by Kumar and Clark, published by Balliere Tindall.
Interestingly, the American Emedicine website (www.emedicine.com/ped/topic1503.htm) quotes 10 per cent.