[Mumps epidemiology in Switzerland: results from the Sentinella surveillance system 1986-1993. Sentinella Work Group]

Perspective in Pediatric Pathology, Chapter 24. Testicular Inflammatory Processes in Pediatric Patients

Acute scrotal pain in children represents a major diagnostic and therapeutic challenge. An important initial differentiation should be made between epididymitis and other processes that cause acute scrotal pain, such as testicular torsion and tumor. Infectious agents disseminating through the blood flow can damage the testis by causing orchitis. On the other hand, infections ascending via spermatic pathways typically lead to epididymitis [ 1 ].

Phylogenetic analysis of clinical mumps virus isolates from vaccinated and non-vaccinated patients with mumps during an outbreak, Switzerland 1998-2000

During the past decade mumps outbreaks have occurred in several European countries with universal vaccination programs probably due to poor efficacy of the Rubini vaccine strain. However, the evolution of vaccine escape mutants has also been considered. A phylogenetic analysis was undertaken on 69 clinical mumps isolates obtained from 39 vaccinated and 22 non-vaccinated mumps cases (and six cases with unknown vaccination status) during an outbreak in 1998-2000. Two major strain clusters (SWI-H, SWI-C) with two subgroups each (SWI-H1/2, SWI-C1/2) were identified, which belonged to genotypes C and H. No association between viral clusters and vaccination status or a specific vaccine strain (Jeryl-Lynn or Rubini) was found. Cluster SWI-C1 occurred more frequently in the Western part of Switzerland (P < 0.001). Isolates causing complicated disease tended to cluster more frequently with SWI-H1 (P = 0.11). Wild-type strains homologous or similar to the Rubini vaccine strain (isolated in Switzerland in 1974) were no longer circulating. Therefore, there was no evidence for vaccine escape mutants. Strain redistribution may have occurred during the past decades. Continuous monitoring of circulating mumps virus populations is needed.

Field evaluation of the clinical effectiveness of vaccines against pertussis, measles, rubella and mumps. The Benevento and Compobasso Pediatricians Network for the Control of Vaccine-Preventable Diseases

Beginning in March 1995, in the adjacent provinces of Benevento and Campobasso in Southern Italy, we carried out a sentinel, paediatrician-based surveillance on pertussis, measles, rubella and mumps with the aim of evaluating the health impact of new vaccination programmes and the objectives of describing the time-space trends and estimating the effectiveness of new vaccinations. The study population consisted of 16,500 children attended by 25 paediatricians. The estimated effectiveness of vaccines for pertussis, measles and rubella were close to the expected values, although a very low effectiveness was calculated for the mumps vaccine. The comparison among children vaccinated with various strains showed a diseases odds ratio of 2.5 for the children vaccinated with Rubini strain. The effectiveness of this strain has to be verified in more rigorous settings.

[Comparison of the efficacy of various strains of mumps vaccine: a school survey]

BACKGROUND

Since the beginning of the program of immunization of children against measles, mumps and rubella (MMR) in 1987, various outbreaks of mumps have occurred in Switzerland, with a significant proportion of cases in immunized children. Previous studies have suggested a possible lack of efficacy of the Rubini vaccine strain, which has been much used in this country.

METHODS

Incidence study of secondary cases of mumps in the schools of Geneva, between March 18th and June 30th 1994.

STUDY POPULATION

During the study period, mumps outbreaks have been observed in 10 school classes. After exclusion of the 10 primary cases, the study population comprised 195 children aged 4 to 12 years.

RESULTS

Raw estimation of vaccine efficacy against mumps was 72.5%. Whereas both the Urabe and Jeryl-Lynn strains showed a significant efficacy, the Rubini strain didn't show any significant protective effect. After adjustment by Poisson regressions for the confounding effect of age, efficacy rates and 95% confidence limits were 75.8% (35.6%, 90.9%) for Urabe; 64.7% (10.6%, 86.0%) for Jeryl-Lynn; and 12.4% (-102%, 62.1%) für Rubini.

CONCLUSION

This study didn't show any protective effect of the Rubini vaccine strain. Furthermore, it demonstrated a statistically significant protective effect of the Urabe and Jeryl-Lynn strains, compared to the Rubini strains. In this conditions the use of the Rubini strain should be restricted to situations of confirmed contra-indications to the other vaccinal strains, as long as its protective efficacy is not clearly demonstrated.

[Mumps epidemiology--worldwide]

Mumps is an acute viral infection that is endemic worldwide and that occurs primarily in school-age children and adolescents. The most prominent manifestation is tender swelling of the parotid gland. The course of the disease is usually mild and selflimited. Meningitis and orchitis, the latter more common in postpubertal persons, are less frequent manifestations of this disease. As characteristic of many viral infections the severity of the illness increases with age. In the present review first the most important epidemiologic parameters of mumps are presented, as well as the various clinical manifestations and complications. Further the epidemiology of mumps in developing and in industrialized countries is discussed. Breakthrough infections with mumps occurring with either low or high vaccination coverage are described.

[A look back at 2 mumps outbreaks]

Two studies are presented. The first one concerns a mumps outbreak in a kindergarten in Geneva in June 1991. Of 26 children, nine (34.6%) got mumps. Of nine children vaccinated with the Rubini vaccine strain, seven had the disease as opposed to only one of 14 children vaccinated with the Urabe strain. The vaccine efficacy of the Rubini strain was estimated at 22% with a 95% confidence interval of -10% to 45%. The second study concerns a cluster of 112 mumps patients seen by a pediatrician in the Bernese Jura region between September 1992 and May 1993. A case-control study was carried out resulting in a vaccine efficacy estimate of 50% with a 95% confidence interval of -19% to 81%. Of the cases, 51 (45.5%) had been vaccinated against mumps, 50 of them (98%) with the Rubini vaccine strain. Of the controls, 30 (61.2%) had been vaccinated, 86.7% of them with Rubini. Methodological problems of case selection and their possible effects on the estimated vaccine efficacy are discussed. The results of these two studies have been confirmed by more recent investigations. In retrospect, we therefore conclude that small studies can serve as early indicators for epidemiological evidence and that they can be finally integrated into a more complete picture.