Subject: PRO> Mumps & Rubini vaccine - Singapore
From: ProMED <>
Date: Mon, 25 Oct 1999 23:15:35 -0400 (EDT)

A ProMED post

Date: Fri, 22 Oct 1999
From: Chan Yow Cheong
ProMED Regional Moderator for Asia
Source: Eurosurveillance Weekly, issue 43, 21 Oct 1999

Resurgence of mumps in Singapore associated with Rubini vaccine
The incidence of mumps has increased in Singapore since the measles, mumps,
and rubella (MMR) vaccine was introduced into the national childhood
immunisation programme in 1990, while the incidence of measles and rubella
has declined (1). Since 1990 three strains of mumps virus - Urabe,
Jeryl-Lynn, and Rubini - have been used in MMR vaccines. The Urabe strain
was withdrawn in 1992 after an increased risk of aseptic meninigitis was
reported in other countries and the Rubini strain was purchased between
1993 and 1995. In more recent years the Jeryl-Lynn strain (vaccine efficacy
75%) has also been used (KT Goh, personal communication). The incidence of
mumps increased from 674 cases in 1997 to 1183 cases in 1998, 2586 cases
were reported in the first seven months of 1999, and it is estimated that
the incidence will reach 200 per 100 000 population by the end of 1999.
Forty-four per cent (258) of 592 cases that arose in the last four months
of 1998 had received MMR vaccine. Of 195 whose mumps vaccine strain was
known, 144 (74%) had received the Rubini strain, 42 (22%) the Jeryl-Lynn
strain, and nine (5%) the Urabe strain. About 75% of cases had received MMR
vaccine between one and four years before developing mumps. 

Epidemiological evidence suggested that the Rubini vaccine strain offered
no protection. One hundred and forty of 1546 children who had been
vaccinated with the Rubini strain developed mumps - an attack rate of 9%.
The short interval between vaccination and illness indicated primary rather
than secondary vaccine failure due waning immunity over time. 

Seroepidemiological evidence showed that the prevalence of mumps antibody
in children aged under 5 years of age was 22% in 1989 before MMR was
introduced. It increased to 72% in 1993 after mumps vaccination with the
Urabe and Jeryl-Lynn strains was introduced, but it fell to 26% in 1998.
The Ministry of Health in Singapore deregistered the MMR vaccine containing
the Rubini strain in May 1999. 

The poor protection of the Rubini strain in mumps vaccine has been noted in
other countries (2-4). In Portugal, Rubini replaced the Urabe strain in MMR
vaccine in October 1992 and resulted in a large increase in the incidence
of mumps in children (5). The highest rates of mumps occurred in children
aged 1 to 4 years during a mumps epidemic in 1995/96. By January 1998 all
Portuguese health centres had begun to use MMR vaccine containing the Jeryl
Lynn strain in place of the Rubini strain (6).

Goh KT. Resurgence of mumps in Singapore caused by the Rubini mumps virus
vaccine strain. Lancet 1999; 354: 1355-6. (

Galazka AM, Robinson SE, Kraigher A. Mumps and mumps vaccine: a global
review. Bull World Health Organ 1999; 77: 3-14. (

Toscani L, Batou M, Bouvier P, Schlanepfer A. Comparaison de l'efficacité
de différentes souches de vaccin ourlien: une enquête en milieu scolare. Soz
Praventivmed 1996; 41: 341-7.

Germann D, Strohle A. Eggenberger K. Steiner CA. Matter I. An outbreak of
mumps in a population partially vaccinated with the Rubini strain. Scand J
Infect Dis 1996; 28: 235-8.

Dias JA, Cordeiro M, Freitas MG, Morgado MR, Silva JL, Nunes LM, et al.
Mumps outbreak in Portugal despite high vaccine coverage - preliminary
report. Eurosurveillance 1996; 1: 25-8. (

Gonçalves G, de Araújo A, Monteiro Cardoso ML. Outbreak of mumps associated
with poor vaccine efficacy - Oporto, Portugal, 1996. Eurosurveillance 1998;
3: 119-21. (

(Reported by Caroline Akehurst,  (, PHLS Communicable
Disease Surveillance Centre, London, England.)