12 to 25 days (median 18 days).
One week before and up to 9 days after the onset of parotitis.
Respiratory droplets and direct salivary contact with an infected person.
In January 1990, vaccination against mumps was introduced in the national childhood immunisation programme when the monovalent measles vaccine was replaced by the trivalent measles, mumps, rubella (MMR) vaccine. Since January 1990, 3 mumps-virus strains have been used in the MMR vaccine: Urabe strain, Jerryl-Lynn strain and Rubini strain. The Urabe strain was substituted by the Rubini strain during 1993-1995. Although the incidence of measles and rubella had declined, that of mumps increased significantly in 1999 and 2000 due to primary vaccine failure (lack of protection by the Rubini strain vaccine). In view of this, the Ministry of Health deregistered the MMR vaccine containing the Rubini strain in May 1999. The current vaccine contains the Jerryl-Lynn strain.
Since 2000, the incidence of mumps has decreased dramatically from 5981 cases in 2000 to 631 cases in 2009 (12.7 cases per 100,000 population).