Outbreak of Mumps Outbreak of Mumps Infection in Oban, Scotland. Infection in Oban, Scotland.

November 2010 to January 2011November 2010 to January 2011

J. Walker, S. Huc, K. Sinka, J. Walker, S. Huc, K. Sinka,

A. Tissington and K. OatesA. Tissington and K. Oates

Outbreak descriptionOutbreak description 119 cases of mumps infection were detected 119 cases of mumps infection were detected

around the Oban area between the 29 around the Oban area between the 29 November 2010 and 31 January 2011November 2010 and 31 January 2011

In mid December, following identification of an In mid December, following identification of an outbreak, all general practices in Oban area outbreak, all general practices in Oban area contacted and asked to notify cases directly to contacted and asked to notify cases directly to health protection teamhealth protection team

Median age of cases - 20 yearsMedian age of cases - 20 years Many cases notified over the Christmas/New Many cases notified over the Christmas/New

Year holiday period, when young people return Year holiday period, when young people return from work and universityfrom work and university

By end of January, more cases in Oban area By end of January, more cases in Oban area (n=119), than the whole of the rest of Scotland (n=119), than the whole of the rest of Scotland (n=90)(n=90)

Mumps cases by onset date, Oban Mumps cases by onset date, Oban outbreak, Nov 2010 – Jan 2011, n = 119outbreak, Nov 2010 – Jan 2011, n = 119

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BackgroundBackground

Mumps, caused by paromyxovirusMumps, caused by paromyxovirus Mainly causes parotitis Mainly causes parotitis Can also cause orchitis, pancreatitis, Can also cause orchitis, pancreatitis,

meningitismeningitis Notifiable disease – reporting to health Notifiable disease – reporting to health

boardsboards Before vaccination available, typically 3 Before vaccination available, typically 3

yearly outbreaks in under 10syearly outbreaks in under 10s

Image of mumps virus protein, Welcome Image of mumps virus protein, Welcome ImagesImages

VaccinationVaccination

Immunisation introduced to the UK in Immunisation introduced to the UK in 1988 as a single dose of MMR for 12-15 1988 as a single dose of MMR for 12-15 monthsmonths

1996 two dose schedule introduced 1996 two dose schedule introduced Uptake rates for first dose MMR at 24 Uptake rates for first dose MMR at 24

months: 93.7% for Scotland, 91.5% for months: 93.7% for Scotland, 91.5% for Oban area (year ending March 2010)Oban area (year ending March 2010)

VaccinationVaccination

Following vaccine controversy rates post Following vaccine controversy rates post 1998 fell reaching a low in Scotland of 1998 fell reaching a low in Scotland of 88.5% and a low in Argyll of 85.6%.88.5% and a low in Argyll of 85.6%.

This cohort, who would have been due This cohort, who would have been due vaccination in 1998 – 2003 would now be vaccination in 1998 – 2003 would now be 8 – 14 years old.8 – 14 years old.

Data from table HPS website available at Data from table HPS website available at http://www.hps.scot.nhs.uk/immvax/mumps.aspxhttp://www.hps.scot.nhs.uk/immvax/mumps.aspx

MMR Vaccine Uptake and Laboratory Confirmed Cases of Mumps, Scotland 2000-2010

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Confirmed cases of mumps in Scotland by year Confirmed cases of mumps in Scotland by year of diagnosis (horizontal axis) and year of birth of diagnosis (horizontal axis) and year of birth (vertical axis)(vertical axis)n= 7049 to 31st Oct 2011n= 7049 to 31st Oct 2011 (data from Alison Potts HPS - (data from Alison Potts HPS - personal communication)personal communication)

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Intermediate risk (mostly well vaccinated)

Procedure following Procedure following notificationnotification

Normally:Normally: A case of mumps is notified and an oral fluid/salivary A case of mumps is notified and an oral fluid/salivary

testing kit is sent out to GP practice testing kit is sent out to GP practice Patient is recalled for testingPatient is recalled for testing Kits sent off to HPA in London for laboratory Kits sent off to HPA in London for laboratory

confirmation, then result after 4-6 weeksconfirmation, then result after 4-6 weeks Vaccination status not routinely recorded when Vaccination status not routinely recorded when

cases are notifiedcases are notifiedDuring Outbreak:During Outbreak: Rapid Lab diagnosis on first cases then clinical Rapid Lab diagnosis on first cases then clinical

diagnosis only diagnosis only 18 were laboratory confirmed and 101 were clinically 18 were laboratory confirmed and 101 were clinically

diagnoseddiagnosed Did collect vaccination historyDid collect vaccination history

Health Protection activity during Health Protection activity during period of increased notificationsperiod of increased notifications

After the first few cases we contacted all After the first few cases we contacted all local practices and asked them to contact us local practices and asked them to contact us promptly and directly about new casespromptly and directly about new cases

We got a vaccination history of each caseWe got a vaccination history of each case We initially requested information on We initially requested information on

vaccination batch numbers to check on vaccination batch numbers to check on “ineffective” batches– however this soon “ineffective” batches– however this soon became unnecessarybecame unnecessary

Parents of children aged 5 – 18 years sent a Parents of children aged 5 – 18 years sent a GP letter and reminded of offer to be GP letter and reminded of offer to be vaccinated with two doses of MMRvaccinated with two doses of MMR

Case informationCase information Cases n=119, 63 females and 56 malesCases n=119, 63 females and 56 males Highest incidence 13-19 year olds (range 4 – 71 years)Highest incidence 13-19 year olds (range 4 – 71 years) 3 cases had complications ( 2 orchitis, 1 pancreatitis) 3 cases had complications ( 2 orchitis, 1 pancreatitis) Vaccination status known for 116 / 119Vaccination status known for 116 / 119 Two doses of MMR n = 53Two doses of MMR n = 53 One dose of MMR n = 33One dose of MMR n = 33 No doses of MMR n = 30No doses of MMR n = 30 For those who had two doses, date of vaccination For those who had two doses, date of vaccination

ranged from 28 Sept 1989 – 13 May 2008ranged from 28 Sept 1989 – 13 May 2008 For those who had one dose, date of vaccination ranged For those who had one dose, date of vaccination ranged

from 5 Dec 1988 – 23 February 2009from 5 Dec 1988 – 23 February 2009

Mumps cases by age and MMR vaccination status, Mumps cases by age and MMR vaccination status, Oban outbreak, Nov 2010 – Jan 2011, n = 119Oban outbreak, Nov 2010 – Jan 2011, n = 119

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ResultsResults Anecdotally index case student at Dundee Univ, Anecdotally index case student at Dundee Univ,

attended former high school dance and after partyattended former high school dance and after party Strain involved was genotype G5 – common UKStrain involved was genotype G5 – common UK The majority of cases under 22 years had The majority of cases under 22 years had

received two doses of vaccine, 53 / 80 (66%)received two doses of vaccine, 53 / 80 (66%) Among those aged 12 or under, 8 / 9 had Among those aged 12 or under, 8 / 9 had

received two doses (89%)received two doses (89%)

45% (n= 53) of all cases had received two 45% (n= 53) of all cases had received two doses of MMRdoses of MMR

Vaccination status of laboratory confirmed Vaccination status of laboratory confirmed mumps cases diagnosed in Scotland between mumps cases diagnosed in Scotland between 2009 and 2011, by age group 2009 and 2011, by age group n=1408, to 31st October 2011n=1408, to 31st October 2011(data from Alison Potts, (data from Alison Potts, HPS – personal communication)HPS – personal communication)

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DiscussionDiscussion Anecdotally not all those affected presented to Anecdotally not all those affected presented to

primary care – numbers may be an primary care – numbers may be an underestimateunderestimate

Strengths of study: Strengths of study:

- well documented immunisation records for - well documented immunisation records for almost all casesalmost all cases

- good relationship with primary care, enabled - good relationship with primary care, enabled good follow-up of casesgood follow-up of cases

- letters to local parents (some came for MMR)- letters to local parents (some came for MMR) Main limitation of our study:Main limitation of our study:

- low number of laboratory confirmed cases- low number of laboratory confirmed cases

Discussion 2Discussion 2 The 45% who were fully vaccinated in our The 45% who were fully vaccinated in our

study is:study is: higher than reports from England and higher than reports from England and

Wales (29%, 31%)[1],[2] Wales (29%, 31%)[1],[2] lower than a report from the Netherlands, lower than a report from the Netherlands,

61% [3] and a report from the US 75% [4]61% [3] and a report from the US 75% [4] In our cohort, in the 13 – 19 year age group, In our cohort, in the 13 – 19 year age group,

76% affected had received two doses of 76% affected had received two doses of MMRMMR

Discussion 3Discussion 3

Published estimates of MMR vaccine Published estimates of MMR vaccine efficacy of mumps component varyefficacy of mumps component vary

88% for one dose and 95% for two doses 88% for one dose and 95% for two doses [3][3]

64% for one dose and 88% for two doses 64% for one dose and 88% for two doses [6][6]

Waning immunity has been noted in older Waning immunity has been noted in older vaccinated individuals vaccinated individuals

ConclusionConclusion Unvaccinated individuals combined with those Unvaccinated individuals combined with those

whose immunity had waned to provide a whose immunity had waned to provide a vulnerable cohort.vulnerable cohort.

These cases highlight the importance of These cases highlight the importance of ensuring high uptake of the recommended two ensuring high uptake of the recommended two doses of MMR.doses of MMR.

Imply a need for further research into long-term Imply a need for further research into long-term mumps immunity in those partially or fully mumps immunity in those partially or fully vaccinated in order to inform future vaccination vaccinated in order to inform future vaccination programmes.programmes.

Although numbers in our cohort are small they Although numbers in our cohort are small they add to growing body of evidence which suggests add to growing body of evidence which suggests that immunity to the mumps component of the that immunity to the mumps component of the vaccine may wane over time [3-6]vaccine may wane over time [3-6]

HPS paper for JCVI adolescent subgroup HPS paper for JCVI adolescent subgroup

ReferencesReferences [1] Walker J, Huc S, Sinka K, Tissington A, Oates K. Ongoing outbreak of mumps [1] Walker J, Huc S, Sinka K, Tissington A, Oates K. Ongoing outbreak of mumps

infection in Oban, Scotland, November 2010 to January 2011. infection in Oban, Scotland, November 2010 to January 2011. Eurosurveillance,Eurosurveillance, 2011; 16(8): pii = 19803.2011; 16(8): pii = 19803.

(2) Yung C., Bukasa A., Brown K., Pebody R. Public Health advice based on routine (2) Yung C., Bukasa A., Brown K., Pebody R. Public Health advice based on routine mumps surveillance in England and Wales. mumps surveillance in England and Wales. EurosurveillanceEurosurveillance, 2010 15 (38):pii=19669, 2010 15 (38):pii=19669

[3] Cohen C., White J.M., Savage E.J., Glynn J.R., Choi Y., Andrews N., Brown D., [3] Cohen C., White J.M., Savage E.J., Glynn J.R., Choi Y., Andrews N., Brown D., Ramsay M.E., Vaccine effectiveness estimates, 2004-2005 mumps outbreak, Ramsay M.E., Vaccine effectiveness estimates, 2004-2005 mumps outbreak, England. England. Emerg Infect DiseaseEmerg Infect Disease, 2007 Jan 13 (1):12-7., 2007 Jan 13 (1):12-7.

[4] Whelan J., van Binnendijik R., Geenland K., Fanoy E., Khargi M., Yap K., Boot H., [4] Whelan J., van Binnendijik R., Geenland K., Fanoy E., Khargi M., Yap K., Boot H., Valtman N., Swaan C., van der Bij A., de Melker H., Hahne S. Ongoing mumps Valtman N., Swaan C., van der Bij A., de Melker H., Hahne S. Ongoing mumps outbreak in a student population with a high vaccination coverage, Netherlands, outbreak in a student population with a high vaccination coverage, Netherlands, 2010. 2010. Euro surveillanceEuro surveillance, 2010; 15 (17) :pii=19554., 2010; 15 (17) :pii=19554.

[5] Centres for Disease Control and Prevention. Update: Mumps Outbreak – New [5] Centres for Disease Control and Prevention. Update: Mumps Outbreak – New York and New Jersey, June 2009 – January 2010. York and New Jersey, June 2009 – January 2010. MMWRMMWR 2010; 59 [ 126 – 129] 2010; 59 [ 126 – 129]

[6] Harling R., White J.M., Ramsaya M.E., Macsween K.F. and van den Bosch C. [6] Harling R., White J.M., Ramsaya M.E., Macsween K.F. and van den Bosch C. The effectiveness of mumps component of the MMR vaccine: a case control study. The effectiveness of mumps component of the MMR vaccine: a case control study. Vaccine 2005 Jul 1l 23 (31) :4070 – 4.Vaccine 2005 Jul 1l 23 (31) :4070 – 4.

AcknowledgementsAcknowledgements

Jean Walker, Sara Huc, Katy Sinka, Jean Walker, Sara Huc, Katy Sinka, Abhayadevi TissingtonAbhayadevi Tissington

Lorraine McKee, HPN NHS HighlandLorraine McKee, HPN NHS Highland

Pauline Jesperson Practice Manager ObanPauline Jesperson Practice Manager Oban

All GPs in North ArgyllAll GPs in North Argyll

Alison Potts, HPSAlison Potts, HPS

Judith Tait, ISDJudith Tait, ISD