Review of the effect of measles vaccination on the epidemiology of SSPE

Tuesday, 19th of November 2013

[source]International Journal of Epidemiology[|source]

When live measles vaccine became available in the early 1960s, the aetiology of SSPE was unknown. Once the association between measles virus and SSPE was established there were concerns that measles vaccine virus might also cause this condition; particularly as SSPE had been associated with milder natural infection. 

In this article, the authors review the impact of measles immunization on the epidemiology of SSPE using comprehensive published and unpublished data. The article shows that measles vaccine directly protects against SSPE by preventing measles infection and has the potential to eliminate SSPE through the elimination of measles. Thee article also adduces that high measles vaccine coverage also offers indirect protection through herd immunity, protecting the unvaccinated from infection or delaying infection until a later age when SSPE risk is reduced. The article concludes that measles-containing vaccines do not appear to: accelerate the course of SSPE; trigger SSPE; or cause SSPE in a person with an established benign persistent wild measles infection. More details are available at:  http://ije.oxfordjournals.org/content/36/6/1334.long

Abstract

BACKGROUND: When measles vaccines were widely introduced in the 1970s, there were concerns that they might cause subacute sclerosing panencephalitis (SSPE): a very rare, late-onset, neurological complication of natural measles infection. Therefore, SSPE registries and routine measles immunization were established in many countries concurrently. We conducted a comprehensive review of the impact of measles immunization on the epidemiology of SSPE and examined epidemiological evidence on whether there was any vaccine-associated risk.

METHODS: Published epidemiological data on SSPE, national SSPE incidence, measles incidence and vaccine coverage, reports of SSPE in pregnancy or shortly post partum were reviewed. Potential adverse relationships between measles vaccines and SSPE were examined using available data.

RESULTS: Epidemiological data showed that successful measles immunization programmes protect against SSPE and, consistent with virological data, that measles vaccine virus does not cause SSPE. Measles vaccine does not: accelerate the course of SSPE; trigger SSPE or cause SSPE in those with an established benign persistent wild measles infection. Evidence points to wild virus causing SSPE in cases which have been immunized and have had no known natural measles infection. Perinatal measles infection may result in SSPE with a short onset latency and fulminant course. Such cases are very rare. SSPE during pregnancy appears to be fulminant. Infants born to mothers with SSPE have not been subsequently diagnosed with SSPE themselves.

CONCLUSIONS: Successful measles vaccination programmes directly and indirectly protect the population against SSPE and have the potential to eliminate SSPE through the elimination of measles. Epidemiological and virological data suggest that measles vaccine does not cause SSPE.