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Published Date: 2007-02-16 09:00:02
Subject: PRO/EDR> Mumps - Spain (Navarra) (02): 2006 - 2007
Archive Number: 20070216.0577

MUMPS - SPAIN (NAVARRA) (02): 2006 - 2007
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Date: Thu 15 Feb 2007
From: ProMED-mail <promed@promedmail.org?
Source: Eurosurveillance weekly releases 2007, Volume 12, Issue 2 [edited]
<http://www.eurosurveillance.org/ew/2007/070215.asp#1>

More than 1300 cases of mumps were reported in
Navarra, an autonomous community in northeast
Spain, between August 2006 and January 2007. The
1st outbreak of 19 cases was reported on 10 Aug
[2006] in Viana, a village with a population of
3860 people. The chain of transmission was
thought to have begun at the summer festival in
Viana, on 22-25 Jul [2006], attended by several
hundred inhabitants of the neighbouring villages
[1]. In the following months, cases of mumps
occurred throughout the entire region of Navarra,
including the capital, Pamplona.
An increase of the number of mumps cases has been
noted since week 32 [5 - 11 August] of 2006,
which has been linked to a series of outbreaks in
places frequented by young adults [illustrated by
a histogram in the original text]. By the end of
2006, 908 cases had been reported. In 2007 so
far, the incidence has continued to increase,
with 489 cases notified up to 2 Feb 2007. The
highest incidence was noted in the 2nd week of
2007 (mid January), with 33 cases per 100 000
inhabitants.
The modal age of patients was 19 years, with 82
percent of cases occurring in patients aged
between 16 and 30 years and 34 percent between 18
and 20 years [illustrated by a histogram in the
original text].
The following case definition was used in this outbreak:
Clinical case: Disease with sudden onset, uni- or
bilateral facial swelling, duration of more than
2 days and limited in time; no other apparent
causes.
Confirmed case: Clinical case with
laboratory-confirmed virology (virus detection,
PCR), serology (IgM positive) or epidemiological
association with other confirmed cases.
Of all reported cases, 210 (15 percent) fulfilled
the criteria for a laboratory-confirmed case
either by virology or serology (IgM positive).
The remaining 85 percent of cases were clinically
compatible with mumps, and very likely to be
confirmed on the basis of epidemiological
association, given the large scale of the
outbreak. The epidemiological investigation,
however, is still ongoing.
Cases with mild symptoms were frequent. Often the
symptoms lasted fewer than 5 days. Severe
complications arose in 17 patients who presented
with orchitis (testicular inflammation) and 3
patients who developed meningitis.
Laboratory results
------------------
Serology was performed for 708 (51 percent)
cases. Of these, 26 percent were serologically
positive for IgM, and 74 percent were positive
for IgG and negative for IgM. As we do not have a
previous serology study for comparison, this
pattern might be due to prior vaccination failure
signified by a decrease of protective antibodies.
We considered these as non laboratory-confirmed
cases, but we included them as part of the
outbreak, because their clinical symptoms and the
epidemiological context were compatible with
mumps.
Discussion
----------
The measles, mumps, and rubella (MMR) vaccine was
introduced in the childhood immunisation
programme in Navarra in 1982, with one dose given
at 15 months of age. Since 1995 a 2nd dose has
been added, initially given at 11 years, and
since 1999, at 6 years. Vaccination coverage with
2 doses has reached more than 90 percent in all
cohorts born after 1985. The Rubini mumps strain
was used in MMR vaccine in Navarra only in the
cohorts born between 1986 and 1988 in a 2nd dose
given at the age of 11 years. Vaccines produced
using the Rubini strain have previously been
found to have low efficacy [2,3,4].
Seroepidemiological surveys show that more than
90 percent of people born before 1975 have
antibodies against mumps [5], acquired during a
clinical or subclinical contact with the virus.
It means that most people in these cohorts are
naturally immunised.
In the recent outbreak, in 143 cases the
vaccination history was known, 112 patients had
received 2 doses of the vaccine. Almost all (138)
patients vaccinated with at least one dose were
aged 25 years or less.
Cases in vaccinated patients can be explained
because the efficacy of the MMR vaccine to
prevent mumps is 75-91 percent [6,7]; and it is
even lower in patients who received only one dose
as children [8,9], especially if the mumps
component included the Rubini strain [2-4, 9,
10]. However, vaccination with the Rubini strain
can explain no more than a small proportion of
cases, since only patients aged between 18 and 20
years (34 percent of all cases) received this
vaccine in the past.
In conclusion, several causes are thought to have
contributed to this outbreak. They include the
incomplete effectiveness of the vaccine against
mumps, the limited coverage of vaccination in the
1st years after introduction, the unvaccinated
population that had not been naturally exposed to
infection in childhood and the low effectiveness
of the Rubini strain. This outbreak could also be
partially explained by the waning immunity in
older vaccinated populations, as has been
suggested by other authors [11].
In order to control this outbreak, the Public
Health Institute of Navarra has recommended the
following measures:
* The maintenance of high vaccination coverage
with 2 doses of the MMR vaccine in the childhood
immunisation programme;
* The vaccination of people born after 1980
who have not received 2 doses of the MMR vaccine;
* A specific vaccination programme for young
adults who were born in 1986, 1987, and 1988 and
received only one MMR dose with Rubini strain;
* The home isolation of cases and vaccination
of all contacts aged 35 or less, who have not
received 2 doses of MMR vaccine and have not
previously been infected with mumps.
[Byline: J Castilla, M Garc�Cenoz, et al]
References:
1. Gerstel L, Lenglet A, Garc�Cenoz M. Mumps
outbreak in young adults following a village
festival in the Navarra region, Spain, August
2006. Euro Surveill 2006;11(11):E061109.4.
<http://www.eurosurveillance.org/ew/2006/061109.asp#4>
2. Akehurst C. Resurgence of mumps in Singapore
associated with Rubini vaccine. Eurosurveillance
1999;10 (43) 991021.
<http://www.eurosurveillance.org/ew/1999/991021.asp#3>
3. Goncalves G, de Araujo A , Monteiro Cardoso
ML. Outbreak of mumps associated with poor
vaccine efficacy - Oporto Portugal 1996. Euro
Surveill 1998; 3(12): 119-21.
<http://www.eurosurveillance.org/em/v03n12/0312-222.asp>
4. Pons C, Pelayo T, Pachon I, Galmes A, Gonzalez
L, Sanchez C et al. Two outbreaks of mumps in
children vaccinated with the Rubini strain in
Spain indicate low vaccine efficacy. Euro
Surveill 2000; 5:80-84.
<http://www.eurosurveillance.org/em/v05n07/0507-223.asp>
5. Centro Nacional de Epidemiologia. Estudio
seroepidemiologico: situacion de las enfermedades
vacunables en Espana. Madrid: Instituto de Salud
Carlos III, 2000.
6. Hersh BS, Fine PE, Kent WK, Cochi SL, Kahn LH,
Zell ER et al. Mumps outbreak in a highly
vaccinated population. J Pediatr 1991;119:187-93.
7. Arnedo Pena A, Monfort Pitarch S, Safont
Adsuara L. Epidemic outbreak of parotiditis in a
school population and efficacy of antiparotiditis
vaccination. Med Clin (Barc) 1989;93:607-10.
8. Sartorius B, Penttinen P, Nilsson J, Johansen
K, Jonsson K, Arneborn M, Lofdahl M, Giesecke J.
An outbreak of mumps in Sweden, February-April
2004. Euro Surveill 2005;10:191-3.
<http://www.eurosurveillance.org/em/v10n09/1009-221.asp>
9. Harling R, White JM, Ramsay ME, Macsween KF,
van den Bosch C. The effectiveness of the mumps
component of the MMR vaccine: a case control
study. Vaccine 2005;23:4070-4.
10. Richard JL, Zwahlen M, Feuz M, Matter HC;
Swiss Sentinel Surveillance Network. Comparison
of the effectiveness of two mumps vaccines during
an outbreak in Switzerland in 1999 and 2000: a
case-cohort study. Eur J Epidemiol 2003;18:569-77.
11. Cohen C, White JM, Savage EJ, Glynn JR, Choi
Y, Andrews N et al. Vaccine effectiveness
estimates, 2004-2005 mumps outbreak, England.
Emerg Infect Dis 2007;13:12-17.
--
ProMED-mail
<promed@promedmail.org>
[A map of Navarra, showing the location of
Pamplona can be viewed at
<http://www.map-of-spain.co.uk/navarre_maps.htm>.
- Mod.CP]

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